A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.
A colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
Relatively complete absence of oxygen in one or more tissues.
Cells specialized to detect chemical substances and relay that information centrally in the nervous system. Chemoreceptor cells may monitor external stimuli, as in TASTE and OLFACTION, or internal stimuli, such as the concentrations of OXYGEN and CARBON DIOXIDE in the blood.
The act of breathing with the LUNGS, consisting of INHALATION, or the taking into the lungs of the ambient air, and of EXHALATION, or the expelling of the modified air which contains more CARBON DIOXIDE than the air taken in (Blakiston's Gould Medical Dictionary, 4th ed.). This does not include tissue respiration (= OXYGEN CONSUMPTION) or cell respiration (= CELL RESPIRATION).
Respiratory retention of carbon dioxide. It may be chronic or acute.
Clinical manifestation consisting of a deficiency of carbon dioxide in arterial blood.
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
The pressure that would be exerted by one component of a mixture of gases if it were present alone in a container. (From McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
An element with atomic symbol O, atomic number 8, and atomic weight [15.99903; 15.99977]. It is the most abundant element on earth and essential for respiration.
The circulation of blood through the BLOOD VESSELS of the BRAIN.
The physical or mechanical action of the LUNGS; DIAPHRAGM; RIBS; and CHEST WALL during respiration. It includes airflow, lung volume, neural and reflex controls, mechanoreceptors, breathing patterns, etc.
Measurement of oxygen and carbon dioxide in the blood.
A transient absence of spontaneous respiration.
A pathologic condition of acid accumulation or depletion of base in the body. The two main types are RESPIRATORY ACIDOSIS and metabolic acidosis, due to metabolic acid build up.
The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.
The balance between acids and bases in the BODY FLUIDS. The pH (HYDROGEN-ION CONCENTRATION) of the arterial BLOOD provides an index for the total body acid-base balance.
A small cluster of chemoreceptive and supporting cells located near the bifurcation of the internal carotid artery. The carotid body, which is richly supplied with fenestrated capillaries, senses the pH, carbon dioxide, and oxygen concentrations in the blood and plays a crucial role in their homeostatic control.
An abnormal increase in the amount of oxygen in the tissues and organs.
The innermost layer of the three meninges covering the brain and spinal cord. It is the fine vascular membrane that lies under the ARACHNOID and the DURA MATER.
A pulmonary ventilation rate faster than is metabolically necessary for the exchange of gases. It is the result of an increased frequency of breathing, an increased tidal volume, or a combination of both. It causes an excess intake of oxygen and the blowing off of carbon dioxide.
A pathological condition caused by lack of oxygen, manifested in impending or actual cessation of life.
The normality of a solution with respect to HYDROGEN ions; H+. It is related to acidity measurements in most cases by pH = log 1/2[1/(H+)], where (H+) is the hydrogen ion concentration in gram equivalents per liter of solution. (McGraw-Hill Dictionary of Scientific and Technical Terms, 6th ed)
A reduction in the amount of air entering the pulmonary alveoli.
Measurement of the volume of gas in the lungs, including that which is trapped in poorly communicating air spaces. It is of particular use in chronic obstructive pulmonary disease and emphysema. (Segen, Dictionary of Modern Medicine, 1992)
The motor nerve of the diaphragm. The phrenic nerve fibers originate in the cervical spinal column (mostly C4) and travel through the cervical plexus to the diaphragm.
The musculofibrous partition that separates the THORACIC CAVITY from the ABDOMINAL CAVITY. Contraction of the diaphragm increases the volume of the thoracic cavity aiding INHALATION.
Physiological processes and properties of the RESPIRATORY SYSTEM as a whole or of any of its parts.
Any method of artificial breathing that employs mechanical or non-mechanical means to force the air into and out of the lungs. Artificial respiration or ventilation is used in individuals who have stopped breathing or have RESPIRATORY INSUFFICIENCY to increase their intake of oxygen (O2) and excretion of carbon dioxide (CO2).
The arterial blood vessels supplying the CEREBRUM.
These include the muscles of the DIAPHRAGM and the INTERCOSTAL MUSCLES.
Failure to adequately provide oxygen to cells of the body and to remove excess carbon dioxide from them. (Stedman, 25th ed)
Respiratory muscles that arise from the lower border of one rib and insert into the upper border of the adjoining rib, and contract during inspiration or respiration. (From Stedman, 25th ed)
One of the CARBONIC ANHYDRASE INHIBITORS that is sometimes effective against absence seizures. It is sometimes useful also as an adjunct in the treatment of tonic-clonic, myoclonic, and atonic seizures, particularly in women whose seizures occur or are exacerbated at specific times in the menstrual cycle. However, its usefulness is transient often because of rapid development of tolerance. Its antiepileptic effect may be due to its inhibitory effect on brain carbonic anhydrase, which leads to an increased transneuronal chloride gradient, increased chloride current, and increased inhibition. (From Smith and Reynard, Textbook of Pharmacology, 1991, p337)
The lower portion of the BRAIN STEM. It is inferior to the PONS and anterior to the CEREBELLUM. Medulla oblongata serves as a relay station between the brain and the spinal cord, and contains centers for regulating respiratory, vasomotor, cardiac, and reflex activities.
Part of the brain located in the MEDULLA OBLONGATA and PONS. It receives neural, chemical and hormonal signals, and controls the rate and depth of respiratory movements of the DIAPHRAGM and other respiratory muscles.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
The act of blowing a powder, vapor, or gas into any body cavity for experimental, diagnostic, or therapeutic purposes.
Inorganic salts that contain the -HCO3 radical. They are an important factor in determining the pH of the blood and the concentration of bicarbonate ions is regulated by the kidney. Levels in the blood are an index of the alkali reserve or buffering capacity.
A central respiratory stimulant with a brief duration of action. (From Martindale, The Extra Pharmocopoeia, 30th ed, p1225)
The part of the brain that connects the CEREBRAL HEMISPHERES with the SPINAL CORD. It consists of the MESENCEPHALON; PONS; and MEDULLA OBLONGATA.
The exchange of OXYGEN and CARBON DIOXIDE between alveolar air and pulmonary capillary blood that occurs across the BLOOD-AIR BARRIER.
Refers to animals in the period of time just after birth.
The rate at which oxygen is used by a tissue; microliters of oxygen STPD used per milligram of tissue per hour; the rate at which oxygen enters the blood from alveolar gas, equal in the steady state to the consumption of oxygen by tissue metabolism throughout the body. (Stedman, 25th ed, p346)
The number of times the HEART VENTRICLES contract per unit of time, usually per minute.
A class of compounds that reduces the secretion of H+ ions by the proximal kidney tubule through inhibition of CARBONIC ANHYDRASES.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
A highly poisonous compound that is an inhibitor of many metabolic processes and is used as a test reagent for the function of chemoreceptors. It is also used in many industrial processes.
HYPOVENTILATION syndrome in very obese persons with excessive ADIPOSE TISSUE around the ABDOMEN and DIAPHRAGM. It is characterized by diminished to absent ventilatory chemoresponsiveness; chronic HYPOXIA; HYPERCAPNIA; POLYCYTHEMIA; and long periods of sleep during day and night (HYPERSOMNOLENCE). It is a condition often related to OBSTRUCTIVE SLEEP APNEA but can occur separately.
Stretch receptors found in the bronchi and bronchioles. Pulmonary stretch receptors are sensors for a reflex which stops inspiration. In humans, the reflex is protective and is probably not activated during normal respiration.
The determination of oxygen-hemoglobin saturation of blood either by withdrawing a sample and passing it through a classical photoelectric oximeter or by electrodes attached to some translucent part of the body like finger, earlobe, or skin fold. It includes non-invasive oxygen monitoring by pulse oximetry.
A state in which there is an enhanced potential for sensitivity and an efficient responsiveness to external stimuli.
The act of BREATHING in.
The interruption or removal of any part of the vagus (10th cranial) nerve. Vagotomy may be performed for research or for therapeutic purposes.
Measurement of the various processes involved in the act of respiration: inspiration, expiration, oxygen and carbon dioxide exchange, lung volume and compliance, etc.
A strain of albino rat used widely for experimental purposes because of its calmness and ease of handling. It was developed by the Sprague-Dawley Animal Company.
The physiological widening of BLOOD VESSELS by relaxing the underlying VASCULAR SMOOTH MUSCLE.

Depression of peripheral chemosensitivity by a dopaminergic mechanism in patients with obstructive sleep apnoea syndrome. (1/1202)

In the present study, respiratory drives to chemical stimuli and peripheral chemosensitivity were evaluated in patients with obstructive sleep apnoea (OSAS). The effects of oral administration of domperidone, a selective dopamine D2-receptor antagonist, were also examined, to study the respiratory effects of endogenous dopamine on peripheral chemoreceptors. Sixteen patients with OSAS and nine normal control subjects were studied. Respiratory responses to hypercapnia and hypoxia were measured using the rebreathing method and isocapnic progressive hypoxia method, respectively. The hypoxic withdrawal test, which measures the decrease in ventilation caused by two breaths of 100% O2 under mild hypercapnic hypoxic conditions (end-tidal oxygen and carbon dioxide tensions approximately 8.0 kPa and 5.3-6.7 kPa, respectively), was used to evaluate peripheral chemosensitivity. In the patients with OSAS, ventilatory responses to hypercapnia and hypoxia were significantly decreased compared with those of control subjects. Hypoxic withdrawal tests showed that peripheral chemosensitivity was significantly lower in patients with OSAS than in normal subjects. Hypercapnic ventilatory response and peripheral chemosensitivity were enhanced by administration of domperidone in the patients with OSAS, although no changes in either of these were observed in the control subjects. The hypoxic ventilatory response and peripheral chemosensitivity in the patients with OSAS were each significantly correlated with severity of hypoxia during sleep. These findings suggest that peripheral chemosensitivity in patients with obstructive sleep apnoea syndrome may be decreased as a result of abnormality in dopaminergic mechanisms and that the reduced chemosensitivity observed in patients with obstructive sleep apnoea syndrome may affect the severity of hypoxia during sleep.  (+info)

Selective potentiation of peripheral chemoreflex sensitivity in obstructive sleep apnea. (2/1202)

BACKGROUND: The chemoreflexes are an important mechanism for regulation of both breathing and autonomic cardiovascular function. Abnormalities in chemoreflex mechanisms may be implicated in increased cardiovascular stress in patients with obstructive sleep apnea (OSA). We tested the hypothesis that chemoreflex function is altered in patients with OSA. METHODS AND RESULTS: We compared ventilatory, sympathetic, heart rate, and blood pressure responses to hypoxia, hypercapnia, and the cold pressor test in 16 untreated normotensive patients with OSA and 12 normal control subjects matched for age and body mass index. Baseline muscle sympathetic nerve activity (MSNA) was higher in the patients with OSA than in the control subjects (43+/-4 versus 21+/-3 bursts per minute; P<0. 001). During hypoxia, patients with OSA had greater increases in minute ventilation (5.8+/-0.8 versus 3.2+/-0.7 L/min; P=0.02), heart rate (10+/-1 versus 7+/-1 bpm; P=0.03), and mean arterial pressure (7+/-2 versus 0+/-2 mm Hg; P=0.001) than control subjects. Despite higher ventilation and blood pressure (both of which inhibit sympathetic activity) in OSA patients, the MSNA increase during hypoxia was similar in OSA patients and control subjects. When the sympathetic-inhibitory influence of breathing was eliminated by apnea during hypoxia, the increase in MSNA in OSA patients (106+/-20%) was greater than in control subjects (52+/-23%; P=0.04). Prolongation of R-R interval with apnea during hypoxia was also greater in OSA patients (24+/-6%) than in control subjects (7+/-5%) (P=0.04). Autonomic, ventilatory, and blood pressure responses to hypercapnia and the cold pressor test in OSA patients were not different from those observed in control subjects. CONCLUSIONS: OSA is associated with a selective potentiation of autonomic, hemodynamic, and ventilatory responses to peripheral chemoreceptor activation by hypoxia.  (+info)

Hyperglycemia and focal brain ischemia. (3/1202)

The influence of hyperglycemic ischemia on tissue damage and cerebral blood flow was studied in rats subjected to short-lasting transient middle cerebral artery (MCA) occlusion. Rats were made hyperglycemic by intravenous infusion of glucose to a blood glucose level of about 20 mmol/L, and MCA occlusion was performed with the intraluminar filament technique for 15, 30, or 60 minutes, followed by 7 days of recovery. Normoglycemic animals received saline infusion. Perfusion-fixed brains were examined microscopically, and the volumes of selective neuronal necrosis and infarctions were calculated. Cerebral blood flow was measured autoradiographically at the end of 30 minutes of MCA occlusion and after 1 hour of recirculation in normoglycemic and hyperglycemic animals. In two additional groups with 30 minutes of MCA occlusion, CO2 was added to the inhaled gases to create a similar tissue acidosis as in hyperglycemic animals. In one group CBF was measured, and the second group was examined for tissue damage after 7 days. Fifteen and 30 minutes of MCA occlusion in combination with hyperglycemia produced larger infarcts and smaller amounts of selective neuronal necrosis than in rats with normal blood glucose levels, a significant difference in the total volume of ischemic damage being found after 30 minutes of MCA occlusion. After 60 minutes of occlusion, when the volume of infarction was larger, only minor differences between normoglycemic and hyperglycemic animals were found. Hypercapnic animals showed volumes of both selective neuronal necrosis and infarction that were almost identical with those observed in normoglycemic, normocapnic animals. When local CBF was measured in the ischemic core after 30 minutes of occlusion, neither the hyperglycemic nor the hypercapnic animals were found to be significantly different from the normoglycemic group. Brief focal cerebral ischemia combined with hyperglycemia leads to larger and more severe tissue damage. Our results do not support the hypothesis that the aggravated injury is caused by any disturbances in CBF.  (+info)

Spike generation from dorsal roots and cutaneous afferents by hypoxia or hypercapnia in the rat in vivo. (4/1202)

The present study aimed at investigating the responsiveness of different parts of the primary afferent neurones to a brief hypoxia, hypercapnia or ischaemia under in vivo conditions. Action potentials were recorded in separate groups of anaesthetized rats from (i) the peripheral end of the central stump of the cut L3, L4 or L5 dorsal root (dorsal root preparation); (ii) the central end of the peripheral stump of the cut saphenous nerve (saphenous-receptor preparation); (iii) the distal end of a segment of the saphenous nerve cut at both ends (axon preparation). In paralysed animals interruption of artificial ventilation for 20-60 s elicited or increased the frequency of action potentials in both the dorsal root and saphenous-receptor preparations. Activation of these preparations was also achieved by inspiration of gas mixtures containing 10-0% oxygen (mixed with nitrogen) or 20-50% carbon dioxide (mixed with oxygen) which elicited in the blood a decrease in PO2 or an increase in PCO2 with a fall in pH. Occlusion of the femoral artery for 3 min also caused spike generation in the saphenous-receptor preparations with little alteration in blood pressure. All these stimuli failed to evoke action potentials in the axon preparations. Systemic (300 mg kg-1 s.c.) or perineural (2%) capsaicin pretreatment failed to inhibit the effect of hypoxia, hypercapnia or ischaemia, indicating a significant contribution of capsaicin-insensitive neurones to the responses. It is concluded that central and peripheral terminals but not axons of primary afferent neurones are excited by a brief hypoxia or hypercapnia and the peripheral terminals by a short local ischaemia as well. Excitation of central terminals by hypoxia or hypercapnia revealed in this way an antidromic activation of dorsal roots in response to natural chemical stimuli.  (+info)

Impact of nasal ventilation on survival in hypercapnic Duchenne muscular dystrophy. (5/1202)

BACKGROUND: Respiratory failure is the commonest cause of death in patients with Duchenne muscular dystrophy (DMD). Life expectancy is less than one year once diurnal hypercapnia develops. This study examines the effects of nasal intermittent positive pressure ventilation (NIPPV) on survival in symptomatic Duchenne patients with established ventilatory failure. METHODS: Nocturnal NIPPV was applied in 23 consecutive patients with DMD of mean (SD) age 20.3 (3.4) years who presented with diurnal and nocturnal hypercapnia. RESULTS: One year and five year survival rates were 85% (95% CI 69 to 100) and 73% (95% CI 53 to 94), respectively. Early changes in arterial blood gas tensions following NIPPV occurred with mean (SD) PO2 increasing from 7.6 (2.1) kPa to 10.8 (1.3) kPa and mean (SD) PCO2 falling from 10.3 (4.5) kPa to 6.1 (1.0) kPa. Improvements in arterial blood gas tensions were maintained over five years. Health perception and social aspects of SF-36 health related quality of life index were reported as equivalent to other groups with nonprogressive disorders using NIPPV. CONCLUSIONS: Nasal ventilation is likely to increase survival in hypercapnic patients with Duchenne muscular dystrophy and should be considered as a treatment option when ventilatory failure develops.  (+info)

Identification of a critical motif responsible for gating of Kir2.3 channel by intracellular protons. (6/1202)

Protons are involved in gating Kir2.3. To identify the molecular motif in the Kir2.3 channel protein that is responsible for this process, experiments were performed using wild-type and mutated Kir2. 3 and Kir2.1. CO2 and low pHi strongly inhibited wild-type Kir2.3 but not Kir2.1 in whole cell voltage clamp and excised inside-out patches. This CO2/pH sensitivity was completely eliminated in a mutant Kir2.3 in which the N terminus was substituted with that in Kir2.1, whereas a similar replacement of its C terminus had no effect. Site-specific mutations of all titratable residues in the N terminus, however, did not change the CO2/pH sensitivity. Using several chimeras generated systematically in the N terminus, a 10-residue motif near the M1 region was identified in which only three amino acids are different between Kir2.3 and Kir2.1. Mutations of these residues, especially Thr53, dramatically reduced the pH sensitivity of Kir2.3. Introducing these residues or even a single threonine to the corresponding positions of Kir2.1 made the mutant channel pH-sensitive. Thus, a critical motif responsible for gating Kir2.3 by protons was identified in the N terminus, which contained about 10 residues centered by Thr53.  (+info)

Exertional dyspnoea in patients with airway obstruction, with and without CO2 retention. (7/1202)

BACKGROUND: Dyspnoea is a common and disabling symptom in patients with cardiopulmonary disease. Unfortunately the mechanisms that produce dyspnoea are still poorly understood. The relationship between dyspnoea and the load on the ventilatory muscles, chemical drive, and ventilatory indices was therefore assessed in patients with obstructive pulmonary disease during an incremental exercise test. METHODS: Fifty patients with a wide range of obstructive pulmonary disease (mean forced expiratory volume in one second (FEV1) 66.1 (28.8)% predicted) performed an incremental cycle ergometer test. A subdivision was made between subjects with CO2 retention (delta PaCO2 > or = 0, n = 22) and subjects without CO2 retention (delta PaCO2 < 0, n = 28) during exercise. During the test dyspnoea (Borg score), oesophageal pressures (mechanical load on the ventilatory muscles (time tension index (TTI), blood gas tensions, and minute ventilation were measured. Correlations for changes in mechanical and chemical factors with changes in dyspnoea score were calculated to assess relevant factors. An analysis of covariance was used to examine whether there was a relationship between dyspnoea score and each of these factors and whether this relationship was different between the subgroups with and without CO2 retention. Multiple regression analysis was used to assess the independent effect of each parameter on dyspnoea sensation. Furthermore, the amplitude of pleural pressure swing ((Pi + Pe)act) generated at maximal work load (Ptot, an indication of the load on all respiratory muscles) was calculated. Analysis of covariance was used to assess whether there was a relationship between tidal volume (VT) and Ptot and whether this relationship was different between the groups (slopes are an expression of the length-tension inappropriateness, LTI). RESULTS: In the total group and the group without CO2 retention a significant correlation between dyspnoea and the increase in the inspiratory time tension index (TTIi) was present. In the group with CO2 retention a significant correlation was seen between dyspnoea and delta PaCO2. The factors delta PaO2, delta VE%MVV and delta (VT/Ti) showed a correlation with a p value of < or = 0.10 both in the total group and in those without CO2 retention. In an analysis of covariance the relationship between dyspnoea score and delta PaCO2 appeared to be significantly different between the two subgroups, being more pronounced in the group with CO2 retention. No other relationships with change in dyspnoea score were found. There was no significant relationship between VT and Ptot in the total group nor in the two subgroups, indicating some length-tension inappropriateness in both groups. CONCLUSIONS: In patients with distinctive pulmonary disease who are normocapnic or hypocapnic the mechanical load (delta TTIi) and length-tension inappropriateness (LTI) on ventilatory muscles seem to be the main determinant of exertional dyspnoea. As soon as hypercapnia occurs, this seems to override all other inputs for dyspnoea.  (+info)

A low concentration of nitrous oxide reduces dyspnoea produced by a combination of hypercapnia and severe elastic load. (8/1202)

We have measured how a low concentration of nitrous oxide affected respiratory sensation and ventilation. Severe dyspnoea was induced in nine normal subjects by a combination of hypercapnia and inspiratory elastic load (50 cm H2O litre-1). Subjects were asked to rate their sensation of respiratory discomfort using a visual analogue scale (VAS) while breathing either 20% nitrous oxide or 20% nitrogen gas mixture. We compared the effects of each gas mixture on respiratory sensation and ventilation using steady-state values of ventilatory variables and VAS scores obtained before, during and after inhalation of each gas mixture. Inhalation of 20% nitrous oxide reduced the sensation of respiratory discomfort from a median VAS score of 6.5 (range 5.0-8.1) before inhalation to 3.6 (2.4-5.9) during inhalation (P < 0.05). There was no significant change in minute ventilation but tidal volume increased during inhalation of 20% nitrogen did not alter VAS scores or ventilatory variables. We found that a low concentration of nitrous oxide greatly alleviated the intensity of dyspnoea without changing respiratory load compensation.  (+info)

In this multicenter study the comparison of the mass flow distribution and redistribution versus the relative blood flow per lobe (as a surrogate for Ventilation/ Perfusion (V/Q) matching) with functional respiratory imaging (FRI) and arterial blood gas (ABG) values will be evaluated in hypercapnic Chronic Obstructive Pulmonary Disease (COPD) patients. Therefore a low dose Computed Tomography (CT) scan will be taken in a population of 30 patients with non-invasive ventilation (NIV) and in a control group of 10 patients without NIV. The CT-scan will be used for FRI ...
TY - JOUR. T1 - Prediction of successful ventilator weaning using airway occlusion pressure and hypercapnic challenge. AU - Montgomery, A. B.. AU - Holle, R. H.O.. AU - Neagley, S. R.. AU - Pierson, D. J.. AU - Schoene, Robert Blair. PY - 1987/1/1. Y1 - 1987/1/1. N2 - We studied eleven patients during 14 attempts at weaning from mechanical ventilation to determine whether central ventilatory drive, measured as airway occlusion pressure 0.1 s after onset of inspiration (P0.1), during spontaneous breathing before and during a brief hypercapnic challenge, could accurately predict the success or failure of the attempt. All patients were recovering from acute respiratory failure and could breath spontaneously for 20 minutes on a T-piece but were judged clinically to be marginal weaning candidates. Minute ventilation (V̇I) and P0.1 were measured while breathing spontaneously and were repeated during a hypercapnic challenge that raised end-tidal PCO2 approximately 10 mm Hg. Seven of the 14 weaning ...
Background: Sleep hypoventilation has been proposed as a cause of progressive hypercapnic respiratory failure and death in patients with severe chronic obstructive pulmonary disease (COPD).. Objective: To determine the effects of nocturnal, non-invasive bi-level pressure support ventilation (NIV) on survival, lung function and quality of life in severe hypercapnic COPD.. Design: A multicentre, open-label, randomized controlled trial of NIV plus long term oxygen therapy (LTOT) versus LTOT alone.. Setting: University Hospital sleep/ respiratory medicine departments.. Patients: Severe, stable, smoking-related COPD (FEV1.0 , 1.5 L or ,50% predicted and FEV1.0/FVC ,60% with awake PaCO2 , 46mmHg and on LTOT for at least 3 months) and age less than 80 years. Patients with sleep apnea (Apnea-hypopnea Index , 20/ hr) or morbid obesity (BMI ,40) were excluded.. Intervention: Night-time bilevel pressure support ventilation.. Measurements: Survival, spirometry, arterial blood gases, polysomnography, general ...
TY - JOUR. T1 - Reversal of attenuation of cerebrovascular reactivity to hypercapnia by a nitric oxide donor after controlled cortical impact in a rat model of traumatic brain injury. AU - Zhang, Fangyi. AU - Sprague, Shane M.. AU - Farrokhi, Farrokh. AU - Henry, Matthew N.. AU - Son, Minnette G.. AU - Vollmer, Dennis G.. PY - 2002/10/1. Y1 - 2002/10/1. N2 - Object. Traumatic brain injury (TBI) attenuates the cerebral vasodilation to hypercapnia. Cortical spreading depression (CSD) also transiently reduces hypercapnic vasodilation. The authors sought to determine whether the CSD elicited by a controlled cortical impact (CCI) injury masks the true effect of TBI on hypercapnic vasodilation, and whether a nitric oxide (NO) donor can reverse the attenuation of hypercapnic vasodilation following CCI. Methods. Anesthetized rats underwent moderate CCI. Cerebral blood flow was monitored with laser Doppler flowmetry and the response to hypercapnia was determined for injured and sham-injured animals. The ...
All information about the latest scientific publications of the Clínica Universidad de Navarra. Hyperleptinaemia, respiratory drive and hypercapnic response in obese patients
1. Endogenous opioids have been implicated in the control of breathing in neonates, but their role in ventilatory control in adults remains unclear.. 2. We studied the relationship between circulating immunoreactive β-endorphin and the ventilatory and mouth occlusion pressure responses to hypercapnia in 12 healthy male subjects. In addition, we examined the effect of repetitive hypercapnia on plasma β-endorphin and Cortisol levels.. 3. A weak but significant negative relationship between the ventilatory response to hypercapnia and basal plasma β-endorphin levels was observed (r = −0.35, P , 0.01). A similar negative relationship was noted between mouth occlusion pressure response to hypercapnia and basal plasma β-endorphin levels (r = −0.36, P , 0.01).. 4. Repetitive hypercapnia prevented the fall in plasma Cortisol that occurred under control conditions (P , 0.02) but had no effect on plasma β-endorphin.. 5. We conclude that plasma β-endorphin may play a role in the central chemical ...
The effects of chronic respiratory failure (hypoxia and hypercapnia) on the contractile properties of cardiac muscle are not established. A study was performed of the isometric contractile properties of isolated papillary muscle removed from rats exposed in a normobaric environmental chamber to 28 days of hypoxia (fractional inspired oxygen (FIO2) 10%, fractional inspired carbon dioxide (FICO2) less than 1%), hypercapnia (FIO2 21%, FICO2 5%), and hypoxia with hypercapnia (FIO2 10%, FICO2 5%). Rats exposed to both hypoxia and hypoxia with hypercapnia developed selective right ventricular hypertrophy. Exposure to hypercapnia alone did not alter right ventricular weight. No change in right ventricular papillary muscle contractility per unit muscle mass was observed as measured by maximum active tension, maximum rate of rise or fall of tension, or time to peak tension. Rat cardiac muscle adapts successfully to the altered acid-base environment and increased work load associated with prolonged ...
This study was undertaken to investigate the contribution of carbon dioxide to respiratory control made by the carotid bodies and vagus nerves. Small eupneically breathing dogs, anesthetized with IV ketamine HCL were subjected to inspired CO2 concentrations of 3% while recording simultaneously tidal volume, inspiratory and expiratory airflow rates, and single neuron activity in or near the ventral respiratory group. The burst activity of the ventral respiratory group neuron was considered to be representative of the final integrated motor output of the brain stem respiratory complex. This data provided information concerning: (1) the relationship between group and airflow, (2) the latency response to CO2, (3) the contribution of the carotid body to the hypercapnic response, (4) the vagal contribution to the hypercapnic response. Several specified measures of neuron activity were altered as airflow patterns changed. Subsequent analyses showed correlation between airflow parameters and neuron ...
Putnam, R. W., Ritucci, N. A., & Dean, J. B. (1997). Effect of Hypercapnia on Intracellular pH in Neurons from Chemosensitive and Insensitive Areas of Medullary Brainstem Slices. The FASEB Journal, 11 (3), 3676 ...
We investigated the effect of different levels of hypercapnia on total pulmonary resistance (RL) in 13 subjects ranging from nonsnorers with low RL to snorers with high RL and dynamic narrowing of the upper airway during inspiration. Added CO2 was ad
The authors studied physiologic peculiarities associated with cardiorespiratory response to hypoxia and hypercapnia in various climate and geographic conditions, to combined effects of hypoxia, hypercapnia and physical burden, in artificial atmosphere with various velocity of hypoxia and hypercapnia...
Authors: Kostoglou K, Debert CT, Poulin MJ, Mitsis GD.. We examined the time-varying characteristics of cerebral autoregulation and hemodynamics during a step hypercapnic stimulus by using recursively estimated multivariate (two-input) models which quantify the dynamic effects of mean arterial blood pressure (ABP) and end-tidal CO2 tension ( [Formula: see text] ) on middle cerebral artery blood flow velocity (CBFV). Beat-to-beat values of ABP and CBFV, as well as breath-to-breath values of [Formula: see text] during baseline and sustained euoxic hypercapnia were obtained in 8 female subjects. The multiple-input, single-output models used were based on the Laguerre expansion technique, and their parameters were updated using recursive least squares with multiple forgetting factors. The results reveal the presence of nonstationarities that confirm previously reported effects of hypercapnia on autoregulation, i.e. a decrease in the MABP phase lead, and suggest that the incorporation of [Formula: ...
Nasal high-flow therapy and non-invasive ventilation performed equally well in people with cCOPD with hypercapnia. NHF could therefore be a valuable addition to existing oxygen delivery devices.
Case 1: A seven-year-old lurcher presented after an episode of severe respiratory distress and collapse, which had been treated by the referring veterinary surgeon with a tracheostomy tube placement. Laryngeal paralysis was diagnosed, and the dog was scheduled to undergo left-sided laryngoplasty. During anaesthesia, the dog developed marked hypercapnia and respiratory acidosis during spontaneous ventilation. Initiation of manual ventilation and endotracheal suctioning did not improve the ventilation. On extubation, a blood clot was discovered, occluding approximately two-third of the endotracheal tube (ETT) lumen. Case 2: A two-month-old Jack Russell terrier was presented for ligation of a patent ductus arteriosus. Intraoperatively, the dog developed sudden severe hypercapnia and hypoxaemia. Manual ventilation was initiated, and two attempts of recruiting the lung were made, which initially improved the ventilation. Postoperatively, before extubation, a second episode of severe hypercapnia and ...
TY - JOUR. T1 - Interaction between the ventilatory and cerebrovascular responses to hypo- and hypercapnia at rest and during exercise. AU - Ogoh, Shigehiko. AU - Hayashi, Naoyuki. AU - Inagaki, Masashi. AU - Ainslie, Philip N.. AU - Miyamoto, Tadayoshi. PY - 2008. Y1 - 2008. N2 - Cerebrovascular reactivity to changes in the partial pressure of arterial carbon dioxide (Pa,CO2) via limiting changes in brain [H+] modulates ventilatory control. It remains unclear, however, how exercise-induced alterations in respiratory chemoreflex might influence cerebral blood flow (CBF), in particular the cerebrovascular reactivity to CO2. The respiratory chemoreflex system controlling ventilation consists of two subsystems: the central controller (controlling element), and peripheral plant (controlled element). In order to examine the effect of exercise-induced alterations in ventilatory chemoreflex on cerebrovascular CO2 reactivity, these two subsystems of the respiratory chemoreflex system and cerebral CO2 ...
The ability of brain cells to regulate intracellular pH (pHi) and several phosphate metabolites was evaluated during 1 h of hypercapnia (inspiratory CO2 fraction of 0.10 and 0.05) in anesthetized rats by 31P high-field (145.6 MHz) nuclear magnetic re
Extended hypercapnia exposure led to the restoration of NBC1 mRNA within 2 wk and to a threefold higher expression at the end of the trial, indicating a differentiated response to acute vs. long-term hypercapnic conditions. As with Na+-K+-ATPase and NHE1, the change in message likely results in changing protein levels. In case of the Na+/HCO3− cotransporter, elevated protein contents would support maintenance of elevated bicarbonate levels (Fig. 6B), as described for several fishes (9, 27, 33, 50). The threefold increment of NBC1 mRNA at the end of the trial emphasizes an important role of this transporter in steady-state acid-base regulation under long-term hypercapnia.. Since HCO3− accumulation under hypercapnia is usually accompanied by a decrease of Cl− concentration, a role for gill Cl−/HCO3− exchange has been postulated (see introduction). However, AE1 mRNA expression in Z. viviparus was only slightly affected, with a trend to decrease initially under hypercapnia, reaching a 50% ...
Although the ventilatory and heart rate responses to hypoxia are known to vary widely among subjects, it is not known how exercise or hypercapnia influence the intersubject variability of these responses. If the intersubject variability increases under such conditions, the inherent response of individuals will have more impact on ventilation and heart rate under a variety of hypoxic conditions during exercise or with hypercapnia than at rest or with normocapnia. Seventeen healthy male volunteers underwent tests to measure ventilatory response to isocapnic progressive hypoxia three times respectively: at rest; during CO2 inhalation (end-tidal carbon dioxide tension (PET,CO2) raised by 5 torr from the baseline level); and during mild exercise with a cycle ergometer (12.5 W) in a supine position. The mean (SEM) value of hypoxic ventilatory response (HVR) (delta minute ventilation (VE)/delta arterial oxygen saturation (Sa,O2) was significantly increased both in the exercise and hypercapnic runs ...
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Hypercapnia happens when you have too much carbon dioxide in your bloodstream. It can happen for several reasons, such as hyperventilation. Learn more.
Study Hypercapnia flashcards from Olivier Mba's Augusta University class online, or in Brainscape's iPhone or Android app. ✓ Learn faster with spaced repetition.
A 60-year-old woman presented to our hospital with severe hypercapnic respiratory failure in the absence of a prior smoking history. She reported a 1-day history of increased dyspnoea and a cough productive of green sputum. Her medical history was significant for severe idiopathic scoliosis, cleft p.... ...
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Principal Investigator:MORIMOTO Yuji, Project Period (FY):2010 - 2012, Research Category:Grant-in-Aid for Scientific Research (C), Section:一般, Research Field:Anesthesiology/Resuscitation studies
A.C. Davidson, I.R. Cameron; Potentiation of the Ventilatory Response to Inhaled CO2 Following Acute Exposure to Hypoxia. Clin Sci (Lond) 1 September 1982; 63 (3): 18P. doi: https://doi.org/10.1042/cs063018Pa. Download citation file:. ...
The successful treatment of hypercapnic respiratory failure with oral modafinil Helen Parnell,1 Ginny Quirke,1 Sally Farmer,1 Sumbo Adeyemo,2 Veronica Varney11Respiratory Department, 2Pharmacy Department, St Helier Hospital, Carshalton, Surrey, UKAbstract: Hypercapnic respiratory failure is common in advanced chronic obstructive pulmonary disease and is usually treated by nasal ventilation. Not all patients requiring such ventilation can tolerate it, with anxiety and phobia influencing their reaction, along with treatment failure. We report the case histories of six patients with hypercapnic respiratory failure who were at risk of death due to refusal of nasal ventilation or its failure despite ongoing treatment. We report their improvement with oral modafinil 200 mg tablets used as a respiratory stimulant, which led to discharge, improved arterial blood gases, and offset further admissions with hypercapnic respiratory failure. This drug is licensed for narcolepsy and is said to stimulate the
TY - JOUR. T1 - Impact of buffering hypercapnic acidosis on cell wounding in ventilator-injured rat lungs. AU - Caples, Sean M.. AU - Rasmussen, Deborah L.. AU - Lee, Won Y.. AU - Wolfert, Marla Z.. AU - Hubmayr, Rolf D.. N1 - Copyright: Copyright 2011 Elsevier B.V., All rights reserved.. PY - 2009/1. Y1 - 2009/1. N2 - We measured the effects of raising perfusate pH on ventilator-induced cell wounding and repair in ex vivo mechanically ventilated hypercapnic rat lungs. Lungs were randomized to one of three perfusate groups: 1) unbuffered hypercapnic acidosis, 2) bicarbonate-buffered hypercapnia, or 3) tris-hydroxy-methyl aminomethane (THAM)-buffered hypercapnia. The membrane-impermeant label propidium iodide was added to the perfusate either during or after injurious ventilation providing a means to subsequently identify transiently wounded and permanently wounded cells in optical sections of subpleural alveoli. Normalizing perfusate pH in hypercapnic preparations attenuated ventilator-induced ...
Davidson, AC, Banham, S, Elliott, M, Kennedy, D, Gelder, C, Glossop, A, Church, AC, Creagh-Brown, B, Dodd, JW, Felton, T et al, Foex, B, Mansfield, L, McDonnell, L, Parker, R, Patterson, CM, Sovani, M and Thomas, L. (2016) BTS/ICS guideline for the ventilatory management of acute hypercapnic respiratory failure in adults ...
Objective: We describe a patient with a prolonged and severe hypercapnia occurring during an episode of status asthmaticus induced by ophthalmic instillation of carteolol. Setting: Prehospital Emergen
Respirology. 2010 Feb;15(2):283-8. doi: 10.1111/j.1440-1843.2009.01665.x. Epub 2009 Nov 23. Multicenter Study; Randomized Controlled Trial; Research Support, Non-U.S. Govt
TY - JOUR. T1 - Management of hypercapnic respiratory failure. T2 - invasive versus non-invasive ventilatory support. AU - Westall, G.. AU - Naughton, M.. PY - 2001/12. Y1 - 2001/12. N2 - Introduction: Recently, non-invasive ventilatory support (NIVS), using a comfortable facial mask, has been used in cooperative patients, and been shown to reduce short and long-term mortality compared with invasive ventilatory support (IVS).2 Aims: We sought to respectively review the management of hypercapnic respiratory failure in patients presenting to the Alfred following the development of a NIVS protocol. Methods: Case records of all patients attending ED with dyspnoea and PaC02 45 mmHg between April and June 1999 were examined. Results: 169 cases were identified (age 60± 23 yrs, 56% female) of whom clinical evidence of COPD (52 %) and congestive heart failure (28%) were identified. As a group, in-hospital mortality was related to presenting PaC02 (9% with PaC02 45-50mmHg; 12% with PaC02 SI60 mmHg and 15 ...
This research examined effects of hypoxic environments on blue crabs, Callinectes sapidus in an estuarine environment. Hypoxic conditions were treated as a multiple stressor involving low dissolved oxygen (D.O.), increased carbon dioxide (hypercapnia), and low pH concurrently. The objectives were to: 1) identify hypoxiahypercapnia by monitoring D.O. and pH as an indicator of hypercapnia in shallow regions of the York River, 2) measure blue crab abundance, and 3) describe blue crab responses to hypoxiahypercapnia via field work at Taskinas Creek and lab measurements of respiration. Ambient D.O. and pH were positively correlated in the Taskinas Creek and York River sites (r= .73). Crab abundance (CPUE) was not significantly different among D.O. and pH ranges. It was concluded that hemolymph blood lactate concentration was not considered a good in situ biomarker for exposure to hypoxickypercapnic conditions. Oxygen uptake was not significantly different between normoxic and hypoxic conditions but was
In the mammalian brain, nitric oxide (NO) is responsible for a vasodilatory tonus as well as the elevation of cerebral blood flow (CBF) induced by hypercapnia. There have been few comparative studies of cerebral vasoregulation in lower vertebrates. Using epi-illumination microscopy in vivo to observe CBF velocity on the brain surface (cerebral cortex), we show that turtles (Trachemys scripta) exposed to hypercapnia (inspired PCO2 = 4.9 kPa) displayed a 62% increase in CBF velocity, while systemic blood pressure remains constant. Exposing turtles to a PCO2 of 14.9 kPa caused an additional increase in CBF velocity, to 104% above control values, as well as a 30% increase in systemic blood pressure. The elevated CBF velocity during hypercapnia could not be blocked by a systemic injection of the NO synthase (NOS) inhibitor NG-nitro-L-arginine (L-NA). However, L-NA injection caused a temporary stop in CBF as well as a persistent increase in systemic blood pressure, suggesting that there is a NO tonus ...
Hypercapnia has been shown in animal experiments to induce pulmonary hypertension. This study measured the sensitivity and time course of the human pulmonary vascular response to sustained (4 h) hypercapnia and hypocapnia. Twelve volunteers undertook three protocols: 1) 4-h euoxic (end-tidal Po(2) = 100 Torr) hypercapnia (end-tidal Pco(2) was 10 Torr above normal), followed by 2 h of recovery with euoxic eucapnia; 2) 4-h euoxic hypocapnia (end-tidal Pco(2) was 10 Torr below normal) followed by 2 h of recovery; and 3) 6-h air breathing (control). Pulmonary vascular resistance was assessed at 0.5- to 1-h intervals by using Doppler echocardiography via the maximum tricuspid pressure gradient during systole. Results show progressive changes in pressure gradient over 1-2 h after the onset or offset of the stimuli, and sensitivities of 0.6 to 1 Torr change in pressure gradient per Torr change in end-tidal Pco(2). The human pulmonary circulatory response to changes in Pco(2) has a slower time course and
BACKGROUND. Noninvasive ventilation (NIV) has a success rate of about 75% during an episode of severe hypercapnic respiratory failure in COPD patients. Recently, a new minimally invasive CO2 extracorporeal removal device (ECCO2-R, Decap; Hemodec, Salerno, Italy) consisting of a pump-driven veno-venous hemofiltration system has been developed. The main features of this system are a low extracorporeal blood flow (,500 ml/min), using a small (14-French) double-lumen catheter, and a relatively small infusion rate of heparin.. METHODS. 15 COPD patients with severe hypercapnic respiratory failure failing NIV after a trial of 2-4 hrs and meeting the criteria for intubation (i.e.pH , 7.30 and hypercapnia (no changes or increased in the PaCO2 baseline values), respiratory rate , 35 b/min, moderate to severe dyspnea) were enrolled.. The average duration of treatment with Decap was 18-24 hours. Intubation was required in 2/15 (13%) patients, and other 2 had procedure related complications (i.e bleeding and ...
100% O2 and CO2 mix (10% CO2 / 90% room air) were delivered in randomised order for 5min, followed by 5 min recovery. Arterial blood gas was taken to verify hyperoxia and hypercapnia. Retinal vessels were imaged every 10 seconds and analysed using ImageJ (percentage relative to baseline). The scotopic threshold response (STR, -5.01 logcd.s/m2) was recorded every minute during the protocol. Results : STZ animals developed hyperglycemia compared to controls (25±0.8 vs 7.7±0.3mmol/L, p,0.05). CO2 produced similar hypercapnia between STZ and control animals (PaCO2 +8.0±2.1mmHg vs +10.4±8.0mmHg, p=0.44), but more vasodilation in STZ animals (arteriole 113±1%, venule 112±1%) compared to controls (arteriole 109±6%, venule 109±2%, p,0.01). Arterioles in STZ animals remained dilated for the duration of hypercapnia, while control arteries reconstricted after 2 minutes. O2 produced hyperoxia similarly between the STZ and control groups (PaO2 +254±34 vs (+263±38mmHg, p=0.85) with no difference in ...
In this study, we prospectively identified adult patients after cardiac arrest and determined the prevalence of hypocapnia exposure and hypercapnia exposure during the first 24 hours after ROSC. Our objective was to test whether post-ROSC exposure to hypocapnia and hypercapnia was associated with poor neurological function at hospital discharge. We found that 36% of patients had any hypocapnia exposure, and 42% had any hypercapnia exposure. By the use of multivariable logistic regression, including multiple sensitivity analyses, we found that both hypocapnia exposure and hypercapnia exposure after ROSC were independent predictors of poor neurological function at hospital discharge. These findings suggest that both hypocapnia and hypercapnia are common during the initial post-ROSC period and are independently associated with poor neurological outcome.. The 2010 American Heart Association Guidelines for Cardiopulmonary Resuscitation and Emergency Cardiovascular Care recommend that ventilation ...
Rationale: Opioids are commonly used to relieve dyspnea, but clinical data are mixed and practice varies widely. Objectives: Evaluate the effect of morphine on dyspnea and ventilatory drive under well-controlled laboratory conditions. Methods: Six healthy volunteers received morphine (0.07 mg/kg) and placebo intravenously on separate days (randomized, blinded). We measured two responses to a CO2 stimulus: (1) perceptual response (breathing discomfort; described by subjects as air hunger) induced by increasing partial pressure of end-tidal carbon dioxide (PetCO2) during restricted ventilation, measured with a visual analog scale (range, neutral to intolerable); and (2) ventilatory response, measured in separate trials during unrestricted breathing. Measurements and Main Results: We determined the PetCO2 that produced a 60% breathing discomfort rating in each subject before morphine (median, 8.5 mm Hg above resting PetCO2). At the same PetCO2 after morphine administration, median breathing ...
Looking for online definition of permissive hypercapnic ventilation in the Medical Dictionary? permissive hypercapnic ventilation explanation free. What is permissive hypercapnic ventilation? Meaning of permissive hypercapnic ventilation medical term. What does permissive hypercapnic ventilation mean?
Gerard J. Criner, MD, FACP, FACCP, Chair and Professor of Thoracic Medicine and Surgery at the Lewis Katz School of Medicine at Temple University and Director of the Temple Lung Center, offered comments to Reuters Health for an article about initiating chronic non-invasive ventilation at home for patients with chronic obstructive pulmonary disease (COPD) and stable hypercapnic respiratory failure. The study, which was conducted by researchers in the Netherlands, was published online in the journal Thorax. Dr. Criner was not involved in the research. MD Alert picked up the Reuters Health report. ...
Carbon dioxide (CO2) is a by-product of aerobic breathing; it is carried and dissolved in blood and bound to haemoglobin and plasma proteins. The arterial carbon dioxide level (pCO2) represents the balance between CO2 production and elimination.1 Avery et al 2 hypothesised that tolerance of pCO2 above the physiological range may … ...
4.4. Ventilatory Responses to Hypoxic Challenges in Morphine-Treated Rats- Episode H1. H1 elicited markedly smaller increases in fr in MOR rats although resting fr was not diminished. As such, morphine elicited latent effects on systems including those within the carotid bodies that drive the hypoxic responses. Our data are consistent with evidence that the negative effects of opioids in humans may be latent since the morphine metabolite, M6G, does not affect resting ventilatory parameters whereas it substantially blunts the ventilatory response to hypercapnic challenge [5]. Since morphine did not markedly blunt the increase in Vt during H1, it is evident that it did not negatively affect neural drive to the chest muscles or diaphragm. This is supported by the finding that Ti in MOR rats (elevated immediately prior to exposure to hypoxia) decreased substantially during H1. Taken together, our data support the concept that morphine affected brainstem centers responsible for generating breathing ...
TY - JOUR. T1 - Hypercapnic blood flow reactivity not increased by α-blockade or cordotomy in piglets. AU - Moore, L. E.. AU - Kirsch, J. R.. AU - Helfaer, M. A.. AU - Greenberg, R. S.. AU - Traystman, R. J.. PY - 1992. Y1 - 1992. N2 - We tested the hypothesis that differential sympathetic innervation explains the attenuated cerebral blood flow (CBF) response to hypercapnia (hyper) in forebrain (fb) compared with brain stem in 1- to 2-wk-old piglets. In pentobarbital sodium-anesthetized piglets, CBF (microspheres) was measured during hypocapnia, normocapnia (normo), and hypercapnia [arterial CO2 partial pressure (Pa(CO)2) of 25, 40, and 65 mmHg, respectively] in random sequence. After pretreatment values were obtained, piglets were randomized to undergo sham treatment (n = 5), high cervical spinal cord transection (n = 6), or pharmacological α-adrenergic blockade (prazosin 1 mg/kg + yohimbine 1 mg/kg, n = 6). After each experimental treatment, CO2 reactivity was again measured. Before ...
Background: The mechanisms underlying cerebral hypercapnic vasodilatation are not fully understood. Objective: To investigate the role of nitric oxide (NO) and ATPsensitive potassium (KATP) channels in basal blood flow regulation and hypercapnia-induced vasodilatation in rabbit cerebral blood ves-
a, b, Representative examples of plethysmographic recordings (breathing frequency) during exposure to hypoxia (10% O2) and hypercapnia (5% CO2) in a wild-type FRA mouse and in a Olfr78−/− FRA mouse. c, Plethysmographic recordings (breathing frequency as a measure of time) of the ventilatory response to hypercapnia (5% CO2) performed on wild-type (n = 10) and Olfr78−/− (n = 10) FRA mice. Each data point represents the mean ± s.e.m. of the values for the group of 10 mice. CO2 (percentage CO2) tensions are indicated at the bottom. d, Breathing frequency during exposure to hypercapnia (5% CO2) in Olfr78−/− FRA mice (n = 10) compared to their wild-type littermates (n = 10). e, Breathing frequency during exposure to hypoxia (10% O2) in Olfr78−/− LEX mice compared to wild-type LEX mice (n = 10 for each genotype, 7 pairs in a C57BL/6 background, 3 pairs in a C57BL/6:129S5 mixed background, 9 out of 10 pairs are sex-matched littermates). f, Breathing frequency during exposure to hypoxia ...
Hypercapnia, elevated partial pressure of CO2 in blood and tissue, develops in many patients with chronic severe obstructive pulmonary disease and other advanced lung disorders. Patients with advanced disease frequently develop bacterial lung infections, and hypercapnia is a risk factor for mortality in such individuals. We previously demonstrated that hypercapnia suppresses induction of NF-κB-regulated innate immune response genes required for host defense in human, mouse, and Drosophila cells, and it increases mortality from bacterial infections in both mice and Drosophila. However, the molecular mediators of hypercapnic immune suppression are undefined. In this study, we report a genome-wide RNA interference screen in Drosophila S2* cells stimulated with bacterial peptidoglycan. The screen identified 16 genes with human orthologs whose knockdown reduced hypercapnic suppression of the gene encoding the antimicrobial peptide Diptericin (Dipt), but did not increase Dipt mRNA levels in air. In ...
1. The effect on respiration of a single dose of propranolol has been studied in normal subjects.. 2. The degree of β-adrenoreceptor blockade was assessed in terms of the impaired heart-rate response to progressive exercise and the plasma propranolol concentration.. 3. No effect of propranolol was demonstrated on either the ventilatory response to rebreathing CO2 in hyperoxia, or the response to progressive isocapnic hypoxia. Simple indices of maximal expiratory flow (FEV1.0% and PEFR) were also unchanged.. 4. The absence of any effect of propranolol on the chemical control of breathing in man is discussed in relation to the conflicting literature.. ...
The human pulmonary vasculature constricts in response to hypercapnia and hypoxia, with important consequences for homeostasis and adaptation. One function of these responses is to direct blood flow away from poorly-ventilated regions of the lung. In humans it is not known whether the stimuli of hypercapnia and hypoxia constrict the pulmonary blood vessels independently of each other or whether they act synergistically, such that the combination of hypercapnia and hypoxia is more effective than the sum of the responses to each stimulus on its own. We independently controlled the alveolar partial pressures of carbon dioxide (Paco 2) and oxygen (Pao 2) to examine their possible interaction on human pulmonary vasoconstriction. Nine volunteers each experienced sixteen possible combinations of four levels of Paco 2 (+6, +1, -4 and -9 mmHg, relative to baseline) with four levels of Pao 2 (175, 100, 75 and 50 mmHg). During each of these sixteen protocols Doppler echocardiography was used to evaluate cardiac
Background: Several factors may affect volume and dimensions of the working space in laparoscopic surgery. The precise impact of these factors has not been well studied. In a porcine model, we used computed tomographic (CT) scanning for measuring working space volume and distances. In a first series of experiments, we studied the relationship between intra-abdominal pressure (IAP) and working space. Methods: Eleven 20 kg pigs were studied under standardized anesthesia and volume-controlled ventilation. Cardiorespiratory parameters were monitored continuously, and blood gas samples were taken at different IAP levels. Respiratory rate was increased when ETCO2 exceeded 7 kPa. Breath-hold CT scans were made at IAP levels of 0, 5, 10, and 15 mmHg. Insufflator volumes were compared to CT-measured volumes. Maximum dimensions of pneumoperitoneum were measured on reconstructed CT images. Results: Respiratory rate had to be increased in three animals. Mild hypercapnia and acidosis occurred at 15 mmHg IAP. ...
From the abstract: Hypercapnia, elevated partial pressure of CO2 in blood and tissue, develops in many patients with chronic severe obstructive pulmonary disease and other advanced lung disorders. Patients with advanced disease frequently develop bacterial lung infections ... We previously demonstrated that hypercapnia suppresses induction of NF-κB-regulated innate immune response genes ... However, the molecular mediators of hypercapnic immune suppression are undefined. In this study, we report a genome-wide RNA interference screen in Drosophila S2* cells stimulated with bacterial peptidoglycan. The screen identified 16 genes with human orthologs whose knockdown reduced hypercapnic suppression of the gene encoding the antimicrobial peptide Diptericin (Dipt), but did not increase Dipt mRNA levels in air. In vivo tests of one of the strongest screen hits, zinc finger homeodomain 2 (Zfh2; mammalian orthologs ZFHX3/ATBF1 and ZFHX4), demonstrate that reducing zfh2 function using a mutation or RNA ...
We investigated whether the involuntary breathing movements (IBM) during the struggle phase of breath holding, together with peripheral vasoconstriction and progressive hypercapnia, have a positive effect in maintaining cerebral blood volume. The central hemodynamics, arterial oxygen saturation, brain regional oxyhemoglobin (bHbO(2)), deoxyhemoglobin, and total hemoglobin changes and IBM were monitored during maximal dry breath holds in eight elite divers. The frequency of IBM increased (by approximately 100%), and their duration decreased ( approximately 30%), toward the end of the struggle phase, whereas the amplitude was unchanged (compared with the beginning of the struggle phase). In all subjects, a consistent increase in brain regional deoxyhemoglobin and total hemoglobin was also found during struggle phase, whereas bHbO(2) changed biphasically: it initially increased until the middle of the struggle phase, with the subsequent relative decline at the end of the breath hold. Mean arterial ...
TY - JOUR. T1 - On the optimization of imaging protocol for the mapping of cerebrovascular reactivity. AU - Ravi, Harshan. AU - Thomas, Binu P.. AU - Peng, Shin Lei. AU - Liu, Hanli. AU - Lu, Hanzhang. PY - 2016/3/1. Y1 - 2016/3/1. N2 - Background To devise an improved blood-oxygen-level-dependent (BOLD) imaging protocol for cerebrovascular reactivity (CVR) measurement that can remove a known artifact of negative values. Methods Theoretical and simulation studies were first performed to understand the biophysical mechanism of the negative CVR signals, through which improved BOLD sequence parameters were proposed. This was achieved by equating signal intensities between cerebrospinal fluid and blood, by means of shortening the echo time (TE) of the BOLD sequence. Then, 10 healthy volunteers were recruited to participate in an experimental study, in which we compared the CVR results of two versions of the optimized (Opt1 and Opt2) protocols with that of the standard protocol at 3 Tesla. Two ...
With weakened respiratory (breathing) muscles, our ability to get rid of carbon dioxide (CO2) is impacted, leading to a retention of it in our blood (called hypercapnia) This hypercapnia is usually more dangerous to us than low oxygen sats (hypoxia) but doctors are conditioned to increasing low sats using oxygen - and the vast majority of doctors seem unaware of our inability to effectively expel CO2 if given O2 ...
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Insufficient ventilation under anesthesia on room air will result in the partial pressure of oxygen in the alveoli becoming insufficient so that unsaturated hemoglobin leaves the lungs (hypoxemia). Also, the elimination of carbon dioxide is decreased hypercapnia and respiratory acidosis Acid base imbalance ...
Nocturnal alterations in gas exchange, such as oxygen desaturation and hypercapnia, are an important clinical problem in patients with chronic obstructive pulmonary disease (COPD). Potential forms of treatment include supplemental oxygen, pharmacolog
OSA leads to increased cardiovascular disease (CVD). The mechanisms underlying vascular dysfunction in OSA include sympathetic activation and oxidative stress (from intermittent hypoxia, hypercapnia, and arousals). These perturbations result in reduced production of endothelium-dependent vasodilators such as nitric oxide (44). Moreover, OSA is associated with a proinflammatory and hypercoagulable state-another pathway that causes vascular injury (45). These mechanisms explain the observation that OSA severity, as indicated by AHI, is significantly associated with risk of stroke (odds ratio 2.5) in patients with type 2 diabetes (46). It should be noted that this study included older and obese populations with a high prevalence of OSA (86%). The independent effects of OSA on CVD should be further examined in lean and younger populations with type 2 diabetes.. There are limited empirical data regarding acceleration of other organ system dysfunction in patients with type 2 diabetes as a result of ...
REPIRATORY FAILURE DEFINITION Failure of the respiratory system to meetthe metabolic demands of the body resulting in hypoxia with or without hypercapnia
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... hypercapnia; crackles, wheezing, & decreased breath sounds; increased bronchial secretions; hyperinflation; frequent lower ...
... is the opposite of hypercapnia. Even when marked, hypocapnia is normally well tolerated. Symptoms include tingling ... where hyperventilation and the subsequent hypocapnia is a cause Hypercapnia - Abnormally high tissue carbon dioxide levels, ...
Also, hypoxaemia and hypercapnia should be avoided. Seizures can induce more damage; accordingly, anticonvulsants should be ...
ISBN 0-7506-3107-4. Abdo, Wilson F; Heunks, Leo MA (October 2012). "Oxygen-induced hypercapnia in COPD: myths and facts". ... hypercapnia). This leads to drowsiness (narcosis), deranged acid-base balance due to respiratory acidosis, and death. Many ... hypercapnia) to levels that may become toxic. In individuals with chronic obstructive pulmonary disease who receive ...
Qureshi, AI; Winter, WC; Bliwise, DL (1999). "Sleep fragmentation and morning cerebrovasomotor reactivity to hypercapnia". ...
hypercapnia Excessive level of carbon dioxide in the body. hyperventilation 1. A deliberate deep breathing to reduce blood ... 2. Rapid breathing as the body's response to hypercapnia. 3. Rapid, often shallow breathing, associated with panic. ...
The infant initially attempts to breathe through the nose, and is unable to; hypercapnia occurs, and many babies instinctively ...
"Depression of ventilatory responses to hypoxia and hypercapnia after pentamorphone". Anesthesia and Analgesia. 71 (4): 377-83. ...
A drop in the oxygen carried in blood is known as hypoxemia; a rise in arterial carbon dioxide levels is called hypercapnia. ... hypercapnia). It is typically caused by a ventilation/perfusion (V/Q) mismatch; the volume of air flowing in and out of the ... hypercapnia, or both), and evidence of increased work of breathing. Respiratory failure causes an altered mental status due to ...
Paul is the first to indicate that yoga induces hypercapnia. He describes yoga positions and exercises for Raja and Hatha yoga ...
Khambatta had to leave the location repeatedly to avoid hypercapnia. One scene required the Ilia probe to slice through a steel ...
Hypercapnia (accumulation of carbon dioxide in the blood) is sometimes encountered; this may cause confusion and - if very ...
Berk, James L.; Levy, Matthew N. (1977). "Profound Reflex Bradycardia Produced by Transient Hypoxia or Hypercapnia in Man". ... hypercapnia) or a decrease in blood levels of oxygen (hypoxia), and transmits that information to the central nervous system ... then the primary cardiac reflex to transient hypercapnia and hypoxia is a profound bradycardia and coronary vasodilation ...
Physiologically, it is well adapted to hypoxia, as well as hypercapnia. Even its sperm are quite functional in low-oxygen ...
Hypercapnia only occurs if severe disease or respiratory muscle fatigue occurs. Metabolism rapidly generates a large quantity ... Alveolar hypoventilation thus leads to an increased PaCO2 (a condition called hypercapnia). The increase in PaCO2 in turn ... Hypoventilation in COPD involves multiple mechanisms, including decreased responsiveness to hypoxia and hypercapnia, increased ...
... hypercapnia-responsive parabrachial neurons in mice". The Journal of Comparative Neurology. 523 (6): 907-920. doi:10.1002/cne. ... appears to be critical for relaying information about hypoxia or hypercapnia (e.g., if one is being suffocated during sleep, ...
Camporesi EM, Esposito B, Cigada M (September 1991). "[Ventilatory response to hypoxia and hypercapnia after intravenous ...
... of hypercapnia in rodent brain with MPI time-series imaging". International Journal on Magnetic Particle Imaging. 6 (2/1). doi: ...
As severe hypercapnia may produce disorientation, panic, hyperventilation, convulsions, unconsciousness, and eventually death. ... Hypercapnia is a condition where there is too much carbon dioxide (CO2) in the blood. Divers may develop this condition for ...
... is also seen in respiratory failure due to carbon dioxide toxicity (hypercapnia). Some drugs are known to cause ...
... hypercapnia). In turn, these conditions of hypoxia and hypercapnia will trigger additional effects on the body. Brain cells ... In any person, hypoxia and hypercapnia have certain common effects on the body. The heart rate will increase, unless there are ... Sicard KM, Duong TQ (April 2005). "Effects of hypoxia, hyperoxia, and hypercapnia on baseline and stimulus-evoked BOLD, CBF, ... hypercapnia and congestive heart failure. The management of obstructive sleep apnea was improved with the introduction of ...
The combined effect of hypoxia and hypercapnia act as a strong stimulus whose main consequence is to increase lactic acid and ... Role of hypoxia and hypercapnia". European Journal of Applied Physiology. 110 (2): 367-77. doi:10.1007/s00421-010-1512-9. PMID ... Buteyko method Hypoventilation Hypoxia Hypercapnia Woorons, Xavier, Hypoventilation training, push your limits!, Arpeh, 2014, ...
Hypercapnia is also thought to be a factor increasing risk of central nervous system oxygen toxicity convulsions. Toxicity of ... This has been studied in altitude medicine, where hypoxia occurs without hypercapnia due to the low ambient pressure. The ... Symptoms and signs of early hypercapnia include flushed skin, full pulse, tachypnea, dyspnea, muscle twitches, reduced neural ... In severe hypercapnia, symptoms progresses to disorientation, panic, hyperventilation, convulsions, unconsciousness, and ...
By definition it causes an increased concentration of carbon dioxide (hypercapnia) and respiratory acidosis. Hypoventilation is ... rather than hypercapnia. Dyspnea Hyperventilation List of terms of lung size and activity "hypoventilation" at Dorland's ...
... in response to environmental hypercapnia". Journal of Comparative Physiology B. 180 (3): 323-335. doi:10.1007/s00360-009-0412-y ...
Tak, S; Jang, J; Lee, K; Ye, JC (2010). "Quantification of CMRO(2) without hypercapnia using simultaneous near-infrared ...
For this reason, early tetrapods may have experienced chronic hypercapnia (high levels of blood CO2). This is not uncommon in ...
Jan Wenzel, Cathrin E. Hansen, Carla Bettoni, Miriam A. Vogt, Beate Lembrich, Rentsenkhand Natsagdorj, Gianna Huber, Josefine Brands, Kjestine Schmidt, Julian C. Assmann, Ines Stölting, Kathrin Saar, Jan Sedlacik, Jens Fiehler, Peter Ludewig, Michael Wegmann, Nina Feller, Marius Richter, Helge Müller-Fielitz, Thomas Walther, Gabriele M. König, Evi Kostenis, Walter Raasch, Norbert Hübner, Peter Gass, Stefan Offermanns, Cor de Wit, Carsten A. Wagner, and Markus Schwaninger ...
A look at hypercapnia, a condition where there is too much carbon dioxide in the blood. Included is detail on symptoms and risk ... Fast facts on hypercapnia: *Hypercapnia symptoms can range from mild to severe. ... Hypercapnia, or hypercarbia, as it is sometimes called, is a condition arising from too much carbon dioxide in the blood.. It ... Symptoms of mild hypercapnia may include headaches, dizziness, and fatigue. The following are considered to be mild symptoms of ...
Permissive hypercapnia (PH) is becoming a widely accepted strategy for decreasing ventilator-induced lung injury [1-13]. It is ... Simon RJ, Mawilmada S, Ivatury RR (1994) Hypercapnia: Is there a cause for concern? J Trauma 37: 74 - 81PubMedCrossRefGoogle ... Feihl F, Perret C (1994) Permissive hypercapnia. How permissive should we be? Am J Respir Crit Care Med 150: 1722 - 1737PubMed ... Permissive hypercapnia (PH) is becoming a widely accepted strategy for decreasing ventilator-induced lung injury [1-13]. It is ...
... hypercapnia drives serum pH down, resulting in respiratory acidosis. Clinically, the effect of hypercapnia on pH is estimated ... and symptoms may relate to this condition or directly to the hypercapnia. Specific symptoms attributable to early hypercapnia ... In severe hypercapnia (generally P a C O 2 {\displaystyle {P_{a_{CO_{2}}}}} greater than 10 kPa or 75 mmHg), symptomatology ... Hypercapnia is generally defined as an arterial blood carbon dioxide level over 45 mmHg (6 kPa). Since carbon dioxide is in ...
Permissive hypercapnia is hypercapnia (i.e. high concentration of carbon dioxide in blood) in respiratory insufficient patients ... Hence the term, "permissive hypercapnia." Altogether, the negative side effects of permissive hypercapnia may outweigh the ... The permissive hypercapnia leads to respiratory acidosis which might have negative side effects, but given that the patient is ... Symptoms of early hypercapnia (i.e. where PaCO2 is elevated but not extremely so) include flushed skin, full pulse, ...
Hypercapnia happens when you have too much carbon dioxide in your bloodstream. It can happen for several reasons, such as ... How is hypercapnia diagnosed?. If your doctor thinks that you have hypercapnia, theyll likely test your blood and breathing to ... What is hypercapnia?. Hypercapnia, or hypercarbia, is when you have too much carbon dioxide (CO2) in your bloodstream. It ... Severe hypercapnia can pose more of a threat. It can prevent you from breathing properly. Unlike with mild hypercapnia, your ...
Hypercapnia Exercise Nitrogen Narcosis Diving Immersion Other: NO exercise at depth Other: exercise at depth Not Applicable ... Hypercapnia: Cognitive Effects and Monitoring. The safety and scientific validity of this study is the responsibility of the ... Hypercapnia. Inert Gas Narcosis. Signs and Symptoms, Respiratory. Signs and Symptoms. Unconsciousness. Consciousness Disorders ...
It forecasts the onset of ocean hypercapnia events for atmospheric CO2 concentrations higher than 650 p.p.m., with hypercapnia ... The onset of ocean hypercapnia (when the partial pressure of CO2 in sea-water exceeds 1,000 micro-atmospheres) is forecast for ... Prediction of the onset and evolution of hypercapnia in the ocean requires a good understanding of annual variations in oceanic ... Such extensive ocean hypercapnia has detrimental implications for fisheries during the twenty-first century. ...
Association of hypercapnia on admission with increased length of hospital stay and severity in patients admitted with community ... Randomised controlled trial to investigate the relationship between mild hypercapnia and cerebral oxygen saturation in patients ...
These findings strongly support the significant role of notoginsenoside R1 in the inhibition of hypoxia-hypercapnia-induced ... Diseases : Hypercapnia : CK(4) : AC(0), Hypertension: Pulmonary : CK(191) : AC(78), Hypoxia : CK(289) : AC(179) ... These findings strongly support the significant role of notoginsenoside R1 in the inhibition of hypoxia-hypercapnia-induced ... Notoginsenoside R1 attenuates hypoxia and hypercapnia-induced vasoconstriction in isolated rat pulmonary arterial rings by ...
Hypercapnia is the opposite of hypocapnia. Causes. Hypercapnia is generally caused by hypoventilation, lung disease, or ... Hypercapnia is a condition where there is too much carbon dioxide (CO2) in the blood. Carbon dioxide is a gaseous product of ... Hypercapnia is generally defined as a blood gas carbon dioxide level over 45 mmHg. Since carbon dioxide is in equilibrium with ... In severe hypercapnia (generally PaCO2 greater than 100 hPa or 75 mmHg), symptomatology progresses to disorientation, panic, ...
We have therefore evaluated the effects of acute hypercapnia on these cardiac indices and the interaction of hypercapnia with ... were unaffected by hypercapnia. Similarly, hypercapnia had no effect on lusitropic indexes reflected by its lack of effect on ... Effects of hypercapnia on hemodynamic, inotropic, lusitropic, and electrophysiologic indices in humans.. Kiely DG1, Cargill RI ... Hypercapnia was found to significantly increase both QTc interval and QT dispersion: 428 +/- 8 vs 411 +/- 3 ms and 48 +/- 2 vs ...
Tb was unaffected by hypercapnia. We conclude that the metabolic and ventilatory responses to hypercapnia are dependent on the ... VI/VCO2 was similar at 10:00 and 22:00 h. VI was significantly elevated by hypercapnia and the response at 22:00 h was 2.3 ... Day-night differences in the respiratory response to hypercapnia in awake adult rats.. Peever JH1, Stephenson R. ... times greater than that at 10:00 h. VT/tI was unchanged at 10:00 h but significantly increased by hypercapnia at 22:00 h. VCO2 ...
"Hypercapnia" is a descriptor in the National Library of Medicines controlled vocabulary thesaurus, MeSH (Medical Subject ... This graph shows the total number of publications written about "Hypercapnia" by people in Harvard Catalyst Profiles by year, ... Influence of propofol on isolated neonatal rat carotid body glomus cell response to hypoxia and hypercapnia. Respir Physiol ... A Genetically Defined Circuit for Arousal from Sleep during Hypercapnia. Neuron. 2017 Dec 06; 96(5):1153-1167.e5. ...
The respiratory responses of 52 diabetics and 65 non-diabetic controls to hypoxia, hypercapnia, and exercise were studied. ... five per cent of the diabetics had evidence of impaired sensitivity to hypoxia or decreased ventilatory response to hypercapnia ...
However, little information exists regarding the potential role of diaphragm mobility on hypercapnia in COPD. A … ... Influence of diaphragmatic mobility on hypercapnia in patients with chronic obstructive pulmonary disease J Korean Med Sci. ... However, little information exists regarding the potential role of diaphragm mobility on hypercapnia in COPD. A new method of ... These findings support a possibility that the reduction in diaphragm mobility relates to hypercapnia in COPD patients. ...
Hypercapnia can also develop due to muscle disease and neurological disease. If you are at risk for hypercapnia, it is ... An Overview of Hypercapnia How this gas can be a problem for you. By ... When hypercapnia occurs, in general, it can result from excess CO2 production or reduced CO2 exhalation from the lungs. There ... Hypercapnia: a nonpermissive environment for the lung. Am J Respir Cell Mol Biol. 2012;46(4):417-21. doi:10.1165/rcmb.2011- ...
... Mayo Clin Proc. 1998 Jan;73(1):51-4. doi: 10.1016/ ... In this setting, severe hypercapnia and acidosis rapidly develop. This case report demonstrates that pulse oximetry is an ... results of blood gas studies 3 1/2 hours postoperatively revealed profound hypercapnia (arterial carbon dioxide tension, 265 mm ...
... hypercapnia. Chronic hypercapnia implies at least 6 weeks exposure to water CO2 partial pressures (PwCO2) of approx. 2mmHg ( ... and is further evidence that chronic hypercapnia did not present a sublethal stress. The fact that hypercapnia did not cause a ... Tolerance of chronic hypercapnia by the European eel Anguilla anguilla. D. J. McKenzie, M. Piccolella, A. Z. Dalla Valle, E. W ... Tolerance of chronic hypercapnia by the European eel Anguilla anguilla. D. J. McKenzie, M. Piccolella, A. Z. Dalla Valle, E. W ...
We describe a patient with a prolonged and severe hypercapnia occurring during an episode of status asthmaticus induced by ... Hypercapnia persisted with a PaCO2 of more than 190 mmHg for 10 h, with pH always less than 7.00. The patient was finally ... Key words Near fatal asthma Mechanical ventilation Hypercapnia Respiratory acidosis Received: 20 April 1998 Accepted: 29 July ... Objective: We describe a patient with a prolonged and severe hypercapnia occurring during an episode of status asthmaticus ...
Tolerance of chronic hypercapnia by the European eel Anguilla anguilla. D. J. McKenzie, M. Piccolella, A. Z. Dalla Valle, E. W ... Tolerance of chronic hypercapnia by the European eel Anguilla anguilla. D. J. McKenzie, M. Piccolella, A. Z. Dalla Valle, E. W ... Tolerance of chronic hypercapnia by the European eel Anguilla anguilla. D. J. McKenzie, M. Piccolella, A. Z. Dalla Valle, E. W ... Tolerance of chronic hypercapnia by the European eel Anguilla anguilla Message Subject (Your Name) has sent you a message from ...
Differential Control of Central Cardiorespiratory Interactions by Hypercapnia and the Effect of Prenatal Nicotine. Zheng-Gui ... Differential Control of Central Cardiorespiratory Interactions by Hypercapnia and the Effect of Prenatal Nicotine ... Differential Control of Central Cardiorespiratory Interactions by Hypercapnia and the Effect of Prenatal Nicotine ... Differential Control of Central Cardiorespiratory Interactions by Hypercapnia and the Effect of Prenatal Nicotine ...
Study of Brain Blood Flow During Induced Hypercapnia (Excess Blood Carbon Dioxide). This study has been completed. ... MR Perfusion Imaging in Hypercapnia: Development of Technical Protocols. Further study details as provided by National ... methods for measuring changes in the brains blood flow during hypercapnia (a condition of excess carbon dioxide in the blood ... design a study of the pharmacological and physiological mechanisms underlying cerebral blood flow increases during hypercapnia. ...
We investigated the effect of different levels of hypercapnia on total pulmonary resistance (RL) in 13 subjects ranging from ... During wakefulness, hypercapnia was associated with decreased RLmax. During steady state +6 mm Hg hypercapnia, RLmax decreased ... The effects of hypercapnia on RLpf paralleled its effect on RLmax. We concluded that (1) the decrease in RL during awake ... Hypercapnia / physiopathology*. Pulmonary Gas Exchange / physiology. Respiratory Mechanics / physiology*. Respiratory Muscles ...
... and several phosphate metabolites was evaluated during 1 h of hypercapnia (inspiratory CO2 fraction of 0.10 and 0.05) in ... Phosphocreatine-to-Pi and Pi-to-beta-ATP ratios changed during hypercapnia and returned to base line after withdrawal of CO2. ... there was an undershoot in brain pHi by 0.07-0.09 units between 2.5 and 20 min of hypercapnia. Three animals exhibited an ... and several phosphate metabolites was evaluated during 1 h of hypercapnia (inspiratory CO2 fraction of 0.10 and 0.05) in ...
... style="width:100%;"> ... Tikhonov, M., Baranov, V., and Kotov, A., "Immersion, Hyperoxia, Hypercapnia: Additive Effect Upon Pulmonary Function," SAE ... we did non find any potentiation of oxygen induced toxic effects upon the lungs during immersion/hyperoxia/hypercapnia ...
The response of ventilation and of heart rate to hypoxia and hypercapnia was determined in eight young normal men age 22-30 yr ... The heart rate response to hypercapnia was measured as the percentage change in heart rate between control values at the start ... Attenuation of the Ventilatory and Heart Rate Responses to Hypoxia and Hypercapnia with Aging in Normal Men. ... Attenuation of the Ventilatory and Heart Rate Responses to Hypoxia and Hypercapnia with Aging in Normal Men. ...
CHRONIC HYPERCAPNIA You will receive an email whenever this article is corrected, updated, or cited in the literature. You can ...
We were unable to demonstrate a fall in awake hypercapnia with NIV, despite a sustained reduction in nocturnal CO2 levels. ... This is the first randomised placebo controlled trial of domiciliary NIV in CF subjects with hypercapnia. The results of this ... There was evidence of gas trapping (residual volume/total lung capacity ratio 59 (8)%), chronic hypercapnia (pH 7.39 (0.02), Pa ... Nocturnal non-invasive bi-level positive pressure ventilation (NIV) is beneficial for stable daytime hypercapnia due to ...
Persistent daytime hypercapnia predicts poor prognosis in OSAS undergoing CPAP therapy. Naoko Kawata, Jiro Terada, Koichiro ... Persistent daytime hypercapnia predicts poor prognosis in OSAS undergoing CPAP therapy. Naoko Kawata, Jiro Terada, Koichiro ... Persistent daytime hypercapnia predicts poor prognosis in OSAS undergoing CPAP therapy. Naoko Kawata, Jiro Terada, Koichiro ... Persistent daytime hypercapnia predicts poor prognosis in OSAS undergoing CPAP therapy Message Subject (Your Name) has sent you ...
  • Hypercapnia is the opposite of hypocapnia . (wikidoc.org)
  • CONCLUSION: These results indicate that hyperventilation induced hypocapnia attenuates the cerebral vasodilatory responses during a subsequent period of rebreathing induced hypercapnia. (wku.edu)
  • Global cerebral oxidative metabolism during hypercapnia and hypocapnia in humans: implications for BOLD fMRI. (semanticscholar.org)
  • Sixty patients with severe traumatic brain injury were randomly divided into three groups (n=20), hypocapnia (group L, PaCO 2 25-30 mmHg), hypercapnia (group H, PaCO 2 50-55 mmHg), and control (group C, PaCO 2 35-45 mmHg) groups. (alliedacademies.org)
  • A European cohort of ventilated newborn babies indicated that hypercapnia was more common than hypocapnia [ 1 ]. (biomedcentral.com)
  • In this situation the hypercapnia can also be accompanied by respiratory acidosis. (wikipedia.org)
  • The permissive hypercapnia leads to respiratory acidosis which might have negative side effects, but given that the patient is in ARDS, improving ventilatory function is more important. (wikipedia.org)
  • In this setting, severe hypercapnia and acidosis rapidly develop. (nih.gov)
  • however, results of blood gas studies 3 1/2 hours postoperatively revealed profound hypercapnia (arterial carbon dioxide tension, 265 mm Hg) and acidosis (pH, 6.65) but confirmed normal oxygen levels (arterial oxygen tension, 213 mm Hg). (nih.gov)
  • The results indicate that, at the levels tested, chronic hypercapnia was not a physiological stress for the eel, which can tolerate extracellular acidosis and extremely low Cl - levels while compensating tissue intracellular pH, and which can meet the O 2 requirements of routine and active metabolism despite profound hypoxaemia. (biologists.org)
  • This case illustrates the cerebral and cardiovascular tolerance of severe and prolonged hypercapnia associated with major acidosis. (springer.com)
  • In the past, hypercapnia and its concomitant hypercapnic acidosis, have been considered to be adverse, and were strictly avoided in the critically ill. (springer.com)
  • Lee KJ, Hernandez G, Gordon JB (2003) Hypercapnic acidosis and compensated hypercapnia in control and pulmonary hypertensive piglets. (springer.com)
  • Hillered L, Ernster L, Siesjo BK (1984) Influence of in vitro lactic acidosis and hypercapnia on respiratory activity of isolated rat brain mitochondria. (springer.com)
  • How does the body compensate for hypercapnia (i.e., respiratory acidosis). (brainscape.com)
  • Thus, HCO 3 − /Cl − exchange may play an important role during alkalosis but might also be operative during hypercapnia-induced acidosis as proposed earlier ( 7 , 19 ). (physiology.org)
  • Sequelae of prolonged hypercapnia include respiratory acidosis Acid base imbalance and increased intracranial pressure Intracranial pressure measurement . (vetstream.com)
  • Such long-lasting modifications in hippocampal synaptic plasticity may contribute to the learning impairments associated with perinatal hypoxic hypercapnia and acidosis. (nii.ac.jp)
  • Numerous studies have shown that acute hypercapnia with PaCO 2 less than 80 mmHg and pH value greater than 7.15 is not harmful to the body, due to the compensatory and buffering capacity of the human body for respiratory acidosis. (alliedacademies.org)
  • Hypercapnia and hypercapnic acidosis in sepsis: Harmful, beneficial or unclear? (monash.edu)
  • The effects of hypercapnia on sepsis are largely related to the direct effect of hypercapnic acidosis on immune function and, as a consequence, of increased cardiac output that subsequently leads to improved tissue oxygenation. (monash.edu)
  • Our aim was to review the effects of compensated hypercapnia and hypercapnic acidosis on sepsis, with a specifi c focus on critically ill patients. (monash.edu)
  • There are no clinical studies investigating clinical outcomes of hypercapnic acidosis or compensated hypercapnia in sepsis and septic shock in critical care settings, thus extrapolation of the experimental results to guide critical care practice is diffi cult. (monash.edu)
  • Clinical studies are needed, especially in critically ill patients, to defi ne the effects of compensated hypercapnia and hypercapnic acidosis that may aid clinicians to improve the outcomes in sepsis. (monash.edu)
  • Hypercapnia with acidosis improves pulmonary gas exchange in repetitive conditions of acute hypoxia by potentiating HPV and preventing pulmonary endothelial dysfunction. (biomedcentral.com)
  • This study investigated, if the beneficial effects of hypercapnia with acidosis are preserved during sustained hypoxia as it occurs, e.g in permissive hypercapnic ventilation in intensive care units. (biomedcentral.com)
  • We employed isolated perfused and ventilated rabbit lungs to determine the influence of hypercapnia with or without acidosis (pH corrected with sodium bicarbonate), and inhibitors of endothelial as well as inducible NO synthase on acute or sustained HPV (180 min) and endothelial permeability. (biomedcentral.com)
  • In hypercapnic acidosis, HPV was intensified in sustained hypoxia, in contrast to hypercapnia without acidosis when HPV was amplified during both phases. (biomedcentral.com)
  • L-N G -Nitroarginine (L-NNA), a non-selective NO synthase inhibitor, enhanced acute as well as sustained HPV under all conditions, however, the amplification of sustained HPV induced by hypercapnia with or without acidosis compared to normocapnia disappeared. (biomedcentral.com)
  • In contrast 1400 W, a selective inhibitor of inducible NO synthase (iNOS), decreased HPV in normocapnia and hypercapnia without acidosis at late time points of sustained HPV and selectively reversed the amplification of sustained HPV during hypercapnia without acidosis. (biomedcentral.com)
  • Hypoxic hypercapnia without acidosis increased capillary filtration coefficient ( Kfc ). (biomedcentral.com)
  • Hypercapnia with and without acidosis increased HPV during conditions of sustained hypoxia. (biomedcentral.com)
  • The increase of sustained HPV and endothelial permeability in hypoxic hypercapnia without acidosis was iNOS dependent. (biomedcentral.com)
  • However, it is still controversial how hypercapnia or acidosis affects pulmonary vascular tone and hypoxic vasconstriction. (biomedcentral.com)
  • One, there is some evidence that respiratory acidosis may be protective in critical illness, so benefits of permissive hypercapnia might extend beyond less lung injury. (neonatalresearch.org)
  • Notoginsenoside R1 attenuates hypoxia and hypercapnia-induced vasoconstriction in isolated rat pulmonary arterial rings by reducing the expression of ERK. (greenmedinfo.com)
  • We have previously hypothesized that Panax notoginseng saponins (PNS) might attenuate hypoxia-hypercapnia-induced pulmonary vasoconstriction. (greenmedinfo.com)
  • The third order pulmonary rings from the Sprague-Dawley rats were treated with different concentrations of notoginsenoside R1 (8, 40, and 100 mg/L, respectively) both before and during the conditions of hypercapnia and hypoxia. (greenmedinfo.com)
  • Although the effects of hypercapnia on the systemic circulation have been well documented, there is still some debate as to whether hypercapnia causes true pulmonary vasoconstriction in vivo. (nih.gov)
  • We have therefore evaluated the effects of acute hypercapnia on these cardiac indices and the interaction of hypercapnia with the systemic and pulmonary vascular beds in humans. (nih.gov)
  • Hypercapnia compared with placebo significantly increased mean pulmonary artery pressure 14 +/- 1 vs 9 +/- 1 mm Hg and pulmonary vascular resistance 171 +/- 17 vs 129 +/- 17 dyne.s.cm-5, respectively. (nih.gov)
  • Thus, acute hypercapnia appears to have no adverse inotropic or lusitropic effects on cardiac function, although repolarization abnormalities, reflected by an increase in QT dispersion, and its effects on pulmonary vasoconstriction may have important sequelae in man. (nih.gov)
  • You can also experience sudden bouts of hypercapnia during exacerbations of a pulmonary condition. (verywellhealth.com)
  • Effect of hypercapnia on total pulmonary resistance during wakefulness and during NREM sleep. (biomedsearch.com)
  • We investigated the effect of different levels of hypercapnia on total pulmonary resistance (RL) in 13 subjects ranging from nonsnorers with low RL to snorers with high RL and dynamic narrowing of the upper airway during inspiration. (biomedsearch.com)
  • Nocturnal non-invasive bi-level positive pressure ventilation (NIV) is beneficial for stable daytime hypercapnia due to kyphoscoliosis, neuromuscular disease and chronic obstructive pulmonary disease (COPD). (bmj.com)
  • Possible benefits of permissive hypercapnia such as diminished lung injury and pulmonary inflammation ( 10 ) might be due to the reduction of lung stretch that occurs when tidal volumes are minimized. (frontiersin.org)
  • Laffey JG, Tanaka M, Engelberts D, et al (2000) Therapeutic hypercapnia reduces pulmonary and systemic injury following in vivo lung reperfusion. (springer.com)
  • Kantores C, McNamara PJ, Teixeira L, et al (2006) Therapeutic hypercapnia prevents chronic hypoxia-induced pulmonary hypertension in the newborn rat. (springer.com)
  • Acute respiratory disorders may lead to sustained alveolar hypoxia with hypercapnia resulting in impaired pulmonary gas exchange. (biomedcentral.com)
  • Diseases and illnesses such as pneumonia, emphysema, pulmonary edema and lung cancer are all at a higher risk of developing hypercapnia. (1stclassmed.com)
  • Human pulmonary vascular responses to hypoxia and hypercapnia. (ox.ac.uk)
  • Hypercapnia also increased pulmonary ventilation in both groups to the same extent. (bvsalud.org)
  • Hypercapnia, or hypercarbia, as it is sometimes called, is a condition arising from too much carbon dioxide in the blood. (medicalnewstoday.com)
  • Hypercapnia (from the Greek hyper = "above" or "too much" and kapnos = "smoke"), also known as hypercarbia and CO2 retention, is a condition of abnormally elevated carbon dioxide (CO2) levels in the blood. (wikipedia.org)
  • Hypercapnia also occurs when the breathing gas is contaminated with carbon dioxide, or respiratory gas exchange cannot keep up with the metabolic production of carbon dioxide, which can occur when gas density limits ventilation at high ambient pressures. (wikipedia.org)
  • Permissive hypercapnia is hypercapnia (i.e. high concentration of carbon dioxide in blood) in respiratory insufficient patients in which oxygenation has become so difficult that the optimal mode of mechanical ventilation (with oxygenation in mind) is not capable of exchanging enough carbon dioxide. (wikipedia.org)
  • Hypercapnia, or hypercarbia, is when you have too much carbon dioxide (CO 2 ) in your bloodstream. (healthline.com)
  • Hypercapnia is a condition where there is too much carbon dioxide (CO 2 ) in the blood. (wikidoc.org)
  • Hypercapnia is generally defined as a blood gas carbon dioxide level over 45 mmHg. (wikidoc.org)
  • Since carbon dioxide is in equilibrium with bicarbonate in the blood, hypercapnia can also result in a high serum bicarbonate (HCO 3 - ) concentration. (wikidoc.org)
  • Hypercapnia is excess carbon dioxide (CO2) build-up in your body. (verywellhealth.com)
  • This study will evaluate magnetic resonance imaging (MRI ) methods for measuring changes in the brain's blood flow during hypercapnia (a condition of excess carbon dioxide in the blood). (clinicaltrials.gov)
  • Permissive hypercapnia is a therapeutic strategy that attempts to minimize baro/volutrauma by reducing tidal volumes, which may result in alveolar hypoventilation with increased blood partial pressure of carbon dioxide (PCO 2 ). (frontiersin.org)
  • A search of the Cochrane Library using the search terms 'carbon dioxide' AND 'Infants' AND 'hypercapnia' was used yielding one result. (bmj.com)
  • However, because horses can develop large discrepancies between their PaCO2 and P E CO 2 during anesthesia PE CO 2 should not be relied upon alone to accurately measure the magnitude of hypercapnia, and PaCO2 should be checked using blood gas analysis (see Measurement of carbon dioxide section below). (vetstream.com)
  • There are times, however, when an excess amount can build up-a condition known as hypercapnia, which is also referred to as hypercarbia or carbon dioxide retention (CO2 retention). (verywellhealth.com)
  • There are many possible causes of hypercapnia, including conditions that result in the production of more carbon dioxide (such as infections or trauma) and those that result in the reduced exhalation of the gas from the lungs (such as some lung diseases). (verywellhealth.com)
  • Hypercapnia is a condition characterized by the presence of high amounts of carbon dioxide (CO2) in the bloodstream. (primehealthchannel.com)
  • The term "hypercapnia" can be defined as abnormal elevation of carbon dioxide levels in the blood. (10faq.com)
  • Hypercapnia can also be known as carbon dioxide retention or hypercarbia. (10faq.com)
  • Hypercapnia or hypercapnea (from the Greek hyper = "above" and kapnos = "smoke"), also known as hypercarbia , is a condition where there is too much carbon dioxide (CO2) in the blood. (apneaboard.com)
  • When carbon dioxide isn't removed from your body it is left in your bloodstream and you can develop hypercapnia. (1stclassmed.com)
  • Hypoxic conditions were treated as a multiple stressor involving low dissolved oxygen (D.O.), increased carbon dioxide (hypercapnia), and low pH concurrently. (vcu.edu)
  • Hypercapnia was induced for 10 minutes by inhalation of 5% carbon dioxide with 21% oxygen and 74% nitrogen. (arvojournals.org)
  • Thereafter he could also find a study that shows of how increased blood concentration of carbon dioxide (hypercapnia) in conscious humans can stimulate the vagus nerve that in turn, manifests as respiratory sinus arrhythmia (RSA). (longdom.org)
  • Acute hypercapnia is called acute hypercapnic respiratory failure (AHRF) and is a medical emergency as it generally occurs in the context of acute illness. (wikipedia.org)
  • The inotropic, lusitropic, and electrophysiologic effects of acute hypercapnia in humans are not known. (nih.gov)
  • During cardiopulmonary bypass, hypoxemia accompanied with mild acute hypercapnia (PaCO 2 68 mmHg) can reduce cerebral oxygen consumption by 30%, while during hypercapnia, the production of nitric oxide induced by neuronal nitric oxide synthase plays an important role in improving the cerebral vasodilation and blood flow [ 4 ]. (alliedacademies.org)
  • Unlike acute hypercapnia, mean whole body intracellular pH values were maintained in a normal range despite arterial pH values which varied between 7.27 and 7.46. (jamanetwork.com)
  • 3. Ventilatory responses to acute hypercapnia and hypoxia were assessed before and half an hour after each protocol. (ox.ac.uk)
  • Hypercapnia symptoms can range from mild to severe. (medicalnewstoday.com)
  • The symptoms of severe hypercapnia require immediate medical attention, as they can cause long-term complications. (medicalnewstoday.com)
  • In severe hypercapnia (generally P a C O 2 {\displaystyle {P_{a_{CO_{2}}}}} greater than 10 kPa or 75 mmHg), symptomatology progresses to disorientation, panic, hyperventilation, convulsions, unconsciousness, and eventually death. (wikipedia.org)
  • Severe hypercapnia can pose more of a threat. (healthline.com)
  • Unlike with mild hypercapnia, your body can't correct severe symptoms quickly. (healthline.com)
  • Severe hypercapnia can cause noticeable and distressing effects. (verywellhealth.com)
  • Severe levels of hypercapnia may also cause a reduction in intracellular pH (pHi), and interfere with cellular metabolism through effects on the function of pH-sensitive proteins (Heisler, 1984 , 1993 ). (biologists.org)
  • We describe a patient with a prolonged and severe hypercapnia occurring during an episode of status asthmaticus induced by ophthalmic instillation of carteolol. (springer.com)
  • Patients with severe acute respiratory distress syndrome (ARDS) and hypercapnia present a formidable treatment challenge. (hindawi.com)
  • We examined the use of esophageal balloon for assessment of transpulmonary pressures to guide mechanical ventilation for successful management of severe hypercapnia. (hindawi.com)
  • Patients with severe ARDS and hypercapnia were studied. (hindawi.com)
  • The use of esophageal balloon as a guide to mechanical ventilation was able to treat severe hypercapnia in ARDS patients. (hindawi.com)
  • Hickling KG, Henderson SJ, Jackson R (1990) Low mortality associated with low volume pressure limited ventilation with permissive hypercapnia in severe adult respiratory distress syndrome. (springer.com)
  • Accordingly, we studied the consequences of administering diazepam to six patients with severe but stable obstructive lung disease and hypercapnia. (annals.org)
  • COPD is a major cause of hypercapnia, though not everyone who has COPD-even severe or end-stage disease-will develop this concern. (verywellhealth.com)
  • On the other hand, symptoms of severe hypercapnia are more pronounced. (verywellhealth.com)
  • Permissive hypercapnia may improve Glasgow scores and prognosis of patients of severe traumatic brain injury without affecting oxygen uptake of brain. (alliedacademies.org)
  • In contrast, during intense exercise or severe hypercapnia forced or active expiration occurs in which the abdominal "expiratory" muscles become actively involved in breathing. (pubfacts.com)
  • Severe hypercapnia is a rare but harmful complication of general anesthesia. (biomedcentral.com)
  • We report the case of a newborn who developed severe hypercapnia with unknown reasons during general anesthesia but recovered well. (biomedcentral.com)
  • This report will advance our understanding about the causes of severe hypercapnia during anesthesia, the possible compensatory mechanisms and the characteristics of neonatal respiratory physiology and intracellular buffering systems. (biomedcentral.com)
  • She developed severe hypercapnia during surgery for unclear reasons. (biomedcentral.com)
  • Intracellular buffering systems play an important role in tolerating severe hypercapnia. (biomedcentral.com)
  • However, severe hypercapnia can also bring some adverse effects in neonates such as periventricular white matter injury, intraventricular hemorrhage and retinopathy of prematurity [ 2 ]. (biomedcentral.com)
  • Here we present and analyze the case of a newborn who experienced severe hypercapnia during general anesthesia but recovered well with no complications. (biomedcentral.com)
  • It is a type of Hypercapnia that is frequently seen in people suffering from severe hypoxic lung disease. (primehealthchannel.com)
  • In contrast, severe hypercapnia (Paco2 100-120 mmHg) increased brain injury, which may be caused by increased brain edema. (asahq.org)
  • Thirty years ago, a publication by Seisjo, entitled 'Cerebral metabolic rate in hypercarbia-a controversy' summarized the current state of knowledge related to the influence of hypercapnia (increased pCO2) on cerebral metabolic rate of oxygen consumption (CMRO2) (Siesjo, 1980). (semanticscholar.org)
  • Since hypoxemia is a major life-threatening condition and hypercapnia is not, one might choose to accept the latter. (wikipedia.org)
  • How does Hypercapnia lead to Hypoxemia ? (brainscape.com)
  • Main stimuli to respiration are decreased arterial PO2 (hypoxemia) and increased arterial PCO2 (hypercapnia). (vetstream.com)
  • This results in a low amount of oxygen in the blood, a condition called hypoxemia , as well as hypercapnia. (verywellhealth.com)
  • Not only can this cause hypercapnia, but it can cause hypoxemia. (1stclassmed.com)
  • IRV's major indication is in patients with ARDS with refractory hypoxemia or hypercapnia in other modes of ventilation. (essaywave.com)
  • To our knowledge, this study is the first to assess the response of MBF to different levels of hypercapnia in healthy humans with PET. (snmjournals.org)
  • Rapid magnetic resonance measurement of global cerebral metabolic rate of oxygen consumption in humans during rest and hypercapnia. (semanticscholar.org)
  • Ventilatory responses to hypercapnia and hypoxia after 6 h passive hyperventilation in humans. (ox.ac.uk)
  • Control of exercise hyperpnea during hypercapnia in humans by: Poon, Chi-Sang, et al. (bisp-surf.de)
  • We conclude that the metabolic and ventilatory responses to hypercapnia are dependent on the time of day. (nih.gov)
  • Respiratory responses of diabetics to hypoxia, hypercapnia, and exercise. (bmj.com)
  • The respiratory responses of 52 diabetics and 65 non-diabetic controls to hypoxia, hypercapnia, and exercise were studied. (bmj.com)
  • Before beginning diazepam therapy they were studied with spirometry, blood gases, and measurement of their ventilatory responses to hypoxia and hypercapnia. (annals.org)
  • Peripheral chemoreceptor control of fetal renin responses to hypoxia and hypercapnia. (ahajournals.org)
  • Sinoaortic denervation attenuated the renin and angiotensin II responses to hypercapnia plus hypoxia. (ahajournals.org)
  • Bernardi L, Hilz M, Stemper B, Passino C, Welsch G, Axelrod FB (2003) Respiratory and cerebrovascular responses to hypoxia and hypercapnia in familial dysautonomia. (springer.com)
  • The objectives were to: 1) identify hypoxiahypercapnia by monitoring D.O. and pH as an indicator of hypercapnia in shallow regions of the York River, 2) measure blue crab abundance, and 3) describe blue crab responses to hypoxiahypercapnia via field work at Taskinas Creek and lab measurements of respiration. (vcu.edu)
  • Comparison of phrenic motoneuron responses to hypercapnia and isocapnic hypoxia by: John, Walter M.S., et al. (bisp-surf.de)
  • However, studies evaluating hemodynamic responses to hypoxia and hypercapnia in rats have shown inconsistent results. (bvsalud.org)
  • Our aim was to evaluate hemodynamic and respiratory responses to different levels of hypoxia and hypercapnia in conscious intact or carotid body -denervated rats . (bvsalud.org)
  • Nevertheless, the hemodynamic and ventilatory responses to hypercapnia did not depend on the activation of the peripheral carotid chemoreceptors. (bvsalud.org)
  • Recent research has shown that moderate hypercapnia is a more scientific and effective treatment. (alliedacademies.org)
  • Influence of moderate hypercapnia on neural activity in monkey by simultaneous intracortical recordings and fMRI at 4.7T . Talk presented at 35th Annual Meeting of the Society for Neuroscience (Neuroscience 2005). (mpg.de)
  • In this study, we used combined intracortical recordings and fMRI in the visual cortex of anesthetized macaque monkeys to show that spontaneous neuronal activity is in fact significantly reduced by moderate hypercapnia. (mpg.de)
  • Mild to moderate hypercapnia (Paco2 60-100 mmHg) is neuroprotective after transient global cerebral I/R injury. (asahq.org)
  • Its rationale is the assumption that transitory effects of hypercapnia are less deleterious than the lung damage produced by conventional attempts to keep a target PaCO 2 around 40 mmHg [13-15]. (springer.com)
  • Hypercapnia persisted with a PaCO 2 of more than 190 mmHg for 10 h, with pH always less than 7.00. (springer.com)
  • Hickling KG, Walsh J, Henderson S, Jackson R (1994) Low mortality rate in adult respiratory distress syndrome using low-volume, pressure-limited ventilation with permissive hypercapnia: a prospective study. (springer.com)
  • Depending on the scenario both forms of hypercapnia may be treated with medication, with mask-based non-invasive ventilation or with mechanical ventilation. (wikipedia.org)
  • Other description about permissive hypercapnia in ARDS patient Mechanical ventilation using high tidal volume (VT) and transpulmonary pressure can damage the lung, causing ventilator-induced lung injury. (wikipedia.org)
  • Permissive hypercapnia, a ventilatory strategy for acute respiratory failure in which the lungs are ventilated with a low inspiratory volume and pressure, has been accepted progressively in critical care for adult, pediatric, and neonatal patients requiring mechanical ventilation and is one of the central components of current protective ventilatory strategies. (wikipedia.org)
  • The response of ventilation and of heart rate to hypoxia and hypercapnia was determined in eight young normal men age 22-30 yr and eight elderly men age 64-73. (jci.org)
  • During a multicenter trial of permissive hypercapnia in extremely low birthweight infants (PHELBI), preterm infants (birthweight 400-1,000 g, gestational age 23 0/7-28 6/7 weeks) requiring mechanical ventilation within 24 h of birth were randomly assigned to a high PCO 2 target or a control group. (frontiersin.org)
  • However, accumulating evidence from experimental and clinical studies demonstrates the potential for mechanical ventilation to directly injure the lungs - a phenomenon termed 'ventilator-induced lung injury (VILI)' - and has mandated a rethink of our approaches to hypercapnia. (springer.com)
  • How does Hypercapnia lead to Increased Alveolar Ventilation ? (brainscape.com)
  • Mechanical ventilation may be required to correct hypercapnia until the underlying condition can be corrected. (vetstream.com)
  • Hypercapnia, as produced by the inhalation of a CO 2 -enriched gas mixture, stimulates ventilation. (physiology.org)
  • The aim is to present our experience with pressure controlled ventilation (PCV) and permissive hypercapnia (PHC) in paediatric patients with acute respiratory distress syndrome (ARDS). (biomedcentral.com)
  • There are a few other things that may cause hypercapnia, such as sleep apnea, obesity, scuba diving, and ventilation during anesthesia. (1stclassmed.com)
  • Permissive hypercapnia is a widely practiced ventilatory strategy to improve patient outcome, in which tidal volume and alveolar ventilation are reduced to decrease the potential for ventilator-induced lung injury. (asahq.org)
  • Symptoms of early hypercapnia (i.e. where PaCO2 is elevated but not extremely so) include flushed skin, full pulse, extrasystoles, muscle twitches, hand flaps, and possibly a raised blood pressure. (wikipedia.org)
  • The heart rate response to hypercapnia was measured as the percentage change in heart rate between control values at the start of the rebreathing test and PACO2 = 55 mm Hg. (jci.org)
  • Permissive hypercapnia, allowing the patient's PaCO2 to increase, is used as a tradeoff to protect the lungs from high airway pressures. (essaywave.com)
  • There are other causes of hypercapnia, as well, including some lung diseases. (medicalnewstoday.com)
  • Permissive hypercapnia (PH) is becoming a widely accepted strategy for decreasing ventilator-induced lung injury [1-13]. (springer.com)
  • Hypercapnia is generally caused by hypoventilation, lung disease, or diminished consciousness. (wikipedia.org)
  • Hypercapnia may develop as a complication of chronic lung diseases such as COPD , bronchiectasis , emphysema , interstitial lung disease, and cystic fibrosis , as well as some neurological and muscle diseases. (verywellhealth.com)
  • Some people who have lung disease measure their own oxygen levels at home with a pulse oximeter , but this device cannot detect hypercapnia. (verywellhealth.com)
  • Permissive hypercapnia has been suggested to attenuate lung injury. (frontiersin.org)
  • Acute respiratory dysfunctions as occurring in intensive care under conditions like the adult respiratory distress syndrome, lung edema or pneumonia, as well as acute exacerbations of chronic obstructive lung disease or acute neuromuscular damage may induce local or global alveolar hypoxia and hypercapnia. (biomedcentral.com)
  • Besides COPD, there are a handful of other lung diseases that can cause hypercapnia. (1stclassmed.com)
  • Many other lung diseases that can cause damage to the alveoli are at a higher risk of developing hypercapnia. (1stclassmed.com)
  • Nerve and muscle conditions can lead to hypercapnia, as the nerves and muscles associated with lung function may not be working correctly. (1stclassmed.com)
  • Intracellular pH of whole body and erythrocytes was measured in patients with moderate chronic stable hypercapnia caused by chronic obstructive lung disease. (jamanetwork.com)
  • There are a handful of medical conditions that can be the cause of hypercapnia. (1stclassmed.com)
  • Obesity can also be a cause of hypercapnia, as your body may not get enough oxygen it needs with too much weight pressing on the lungs. (1stclassmed.com)
  • There was no significant effect of hypercapnia on PRA, ANG II, or ALDO. (nih.gov)
  • Furthermore, although C a O 2 was reduced by approximately 50% at the highest P CO 2 , there was no effect of hypercapnia on the eels' tolerance of hypoxia, aerobic metabolic scope or sustained swimming performance. (biologists.org)
  • The aim of the present study was to determine the effect of hypercapnia on motor neuromuscular activity of the human triceps surae muscle. (hokudai.ac.jp)
  • During NREM sleep, low levels of hypercapnia did not affect RL. (biomedsearch.com)
  • Hypercapnia (increased pCO2) sometimes needs to be tolerated in order to achieve these lower tidal volumes. (wikipedia.org)
  • Specific symptoms attributable to early hypercapnia are dyspnea (breathlessness), headache, confusion and lethargy. (wikipedia.org)
  • We hypothesised that nocturnal NIV would improve QoL, functional and physiological outcomes in subjects with stable CF with impaired nocturnal gas exchange and daytime hypercapnia. (bmj.com)
  • Our study objectives were to investigate the survival and explore prognostic factors in OSAS with daytime hypercapnia undergoing CPAP therapy. (ersjournals.com)
  • Kawata N, Terada J, Tatsumi K (2016) Persistent daytime hypercapnia predicts poor prognosis in OSAS undergoing CPAP therapy. (springer.com)
  • Due to the mechanisms that regulate the body's CO2 level, it is rare for someone who is healthy to develop medically significant hypercapnia. (verywellhealth.com)
  • Due to these regulatory pathways, medically significant hypercapnia in otherwise healthy individuals is rare. (verywellhealth.com)
  • Various respiratory conditions, including COPD, may cause hypercapnia. (medicalnewstoday.com)
  • Although not everyone with COPD will develop hypercapnia, a person's risk increases as their COPD progresses. (medicalnewstoday.com)
  • What does hypercapnia have to do with COPD? (healthline.com)
  • Not everyone with COPD will get hypercapnia. (healthline.com)
  • However, little information exists regarding the potential role of diaphragm mobility on hypercapnia in COPD. (nih.gov)
  • These findings support a possibility that the reduction in diaphragm mobility relates to hypercapnia in COPD patients. (nih.gov)
  • This should not be alarming for those with COPD, as not everyone with COPD will developing hypercapnia. (1stclassmed.com)
  • Influence of propofol on isolated neonatal rat carotid body glomus cell response to hypoxia and hypercapnia. (harvard.edu)
  • The ability of brain cells to regulate intracellular pH (pHi) and several phosphate metabolites was evaluated during 1 h of hypercapnia (inspiratory CO2 fraction of 0.10 and 0.05) in anesthetized rats by 31P high-field (145.6 MHz) nuclear magnetic resonance spectroscopy. (biomedsearch.com)
  • 0.05) during hypercapnia. (arvojournals.org)
  • Contrary to our expectation, we did non find any potentiation of oxygen induced toxic effects upon the lungs during immersion/hyperoxia/hypercapnia exposures. (sae.org)
  • To investigate the effect of O 2 and CO 2 inhalation (hyperoxia and hypercapnia) on retinal blood vessel calibre and inner retinal function at early stages in the streptozotocin (STZ) model of diabetes. (arvojournals.org)
  • Arterial blood gas was taken to verify hyperoxia and hypercapnia. (arvojournals.org)
  • Hypercapnia and hyperoxia produce robust vasodilation and vasoconstriction respectively. (arvojournals.org)
  • Effects of hypoxia, hyperoxia, and hypercapnia on baseline and stimulus-evoked BOLD, CBF, and CMRO2 in spontaneously breathing animals. (harvard.edu)
  • Hypercapnia: Permissive, Therapeutic, or Not at All? (springer.com)
  • Laffey JG, Jankov RP, Engelberts D, et al (2003) Effects of therapeutic hypercapnia on mesenteric ischemia-reperfusion injury. (springer.com)
  • The protective effects of so called 'therapeutic hypercapnia' remain experimental at present, but promising laboratory studies suggest potential roles for the eventual selective application at the bedside. (minervamedica.it)
  • Role of nitric oxide in regulating cerebrocortical oxygen consumption and blood flow during hypercapnia. (semanticscholar.org)
  • Day-night differences in the respiratory response to hypercapnia in awake adult rats. (nih.gov)
  • In cases where symptoms are mild and develop slowly over time, people may not even realize they have hypercapnia. (medicalnewstoday.com)
  • Symptoms of mild hypercapnia may include headaches, dizziness, and fatigue. (medicalnewstoday.com)
  • Symptoms of hypercapnia can sometimes be mild. (healthline.com)
  • When hypercapnia is mild, many people do not even realize they have the condition, especially when it develops slowly over time. (verywellhealth.com)
  • Activities that may limit you from breathing in fresh air, such as scuba diving or being on a ventilator during anesthesia, can also cause hypercapnia. (healthline.com)
  • Hypercapnia is often used to accelerate emergence from general anesthesia in the operating room, but little is known about the postoperative effects that may carry over to recovery in the post anesthesia care unit. (usu.edu)
  • Neonates are vulnerable to hypercapnia during anesthesia for their characteristic respiratory physiology. (biomedcentral.com)
  • Mclntyre RC, Haenel JV, Moore FA, Read RR, Burch JM, Moore EE (1994) Cardiopulmonary effects of permissive hypercapnia in the management of adult respiratory distress syndrome. (springer.com)
  • Altogether, the negative side effects of permissive hypercapnia may outweigh the benefits. (wikipedia.org)
  • Often, hypercapnia does not cause obvious effects, and most people do not notice or complain of symptoms. (verywellhealth.com)
  • Because these effects are so vague, you might not realize that they are caused by hypercapnia. (verywellhealth.com)
  • The effects of hypercapnia on RLpf paralleled its effect on RLmax. (biomedsearch.com)
  • Effects of hypercapnia on brain pHi and phosphate metabolite regulation by 31P-NMR. (biomedsearch.com)
  • We investigated the acute effects of warming (W), warming plus hypercapnia (WHc, ~1800 μatm CO2), warming plus hypoxia (WHo, ~12.1 kPa O2), and a combined exposure of all three drivers (Deadly Trio, DT) on king scallops (Pecten maximus). (awi.de)
  • The aim of this study was to evaluate the effects of permissive hypercapnia on Cerebral Oxygen Metabolism (COM) and brain function in patients with craniocerebral trauma surgery. (alliedacademies.org)
  • There are very few clinical studies investigating the effects of hypercapnia in prevention of sepsis and in established sepsis. (monash.edu)
  • The results reveal the presence of nonstationarities that confirm previously reported effects of hypercapnia on autoregulation, i.e. a decrease in the MABP phase lead, and suggest that the incorporation of [Formula: see text] as an additional model input yields less time-varying estimates of dynamic pressure autoregulation obtained from single-input (ABP-CBFV) models. (cerebralautoregulation.com)
  • Permissive hypercapnia is a widely practiced protective ventilatory strategy that has significant protective effects on several models of in vitro and in vivo neuronal injury. (asahq.org)
  • However, conclusive effects of permissive hypercapnia on cerebral ischemia are still unknown. (asahq.org)
  • Effects of prolonged physical training on ventilatory response to hypercapnia by: Miyamura, Miharu, et al. (bisp-surf.de)
  • Chronic hypercapnia, where metabolic compensation is usually present, may cause symptoms but is not generally an emergency. (wikipedia.org)
  • Hypercapnia had no effect on such indicators of stress as plasma catecholamine or cortisol levels, plasma osmolality or standard metabolic rate. (biologists.org)
  • Constant hypercapnia (60 mm Hg) and lowpH (pH = 6.5) both significantly increased the duration of the SDA response by 22% and 29%, respectively.Hypercapnia had no effect on standard metabolic rate,while constant or oscillating hypercapnia significantly lowered the maximum metabolic rate compared to controls, causing a significant reduction of the aerobic scope during constant hypercapnia. (dtu.dk)
  • Cerebral metabolic rate in hypercapnia: controversy continues. (semanticscholar.org)
  • Cerebral metabolic rate of oxygen (CMRO2) can be obtained with magnetic resonance imaging (MRI) by calibrating BOLD using hypercapnia. (mpg.de)
  • We use these optical measurements during graded hypercapnia to test the iso-metabolic assumption, and demonstrate an apparent increase in brain metabolism at higher inhaled CO 2 levels. (ismrm.org)
  • Hypercapnia is a medical emergency that can give rise to life-threatening complications. (primehealthchannel.com)
  • Despite augmentation of sympathomimetic output permissive hypercapnia tends to induce systemic vasodilation, particularly in hypovolemic patients. (blogspot.com)
  • To maintain adequate hemodynamic, permissive hypercapnia may require both beta blocker to counter tachycardia and adequate volume replacement to counter vasodilation. (blogspot.com)
  • QUESTION 2: Is permissive hypercapnia beneficial to preterm infants? (bmj.com)
  • The technical experience obtained in this study will be used to design a study of the pharmacological and physiological mechanisms underlying cerebral blood flow increases during hypercapnia. (clinicaltrials.gov)
  • Hare GM, Kavanagh BP, Mazer CD, et al (2003) Hypercapnia increases cerebral tissue oxygen tension in anesthetized rats. (springer.com)
  • We conclude that 1) hypercapnia more potently increases plasma renin activity than does hypoxia in late gestation fetal sheep, 2) arterial pH may be the relevant signal perceived by the peripheral arterial chemoreceptors for the control of the renin-angiotensin system during asphyxia, and 3) the cardiovascular response to hypoxia is mediated, in part, by peripheral arterial chemoreceptors. (ahajournals.org)
  • Hypercapnia produced similar increases in pSTR (Cit 144±13%, STZ 152±16% P=0.49) and nSTR amplitude (Cit 49±12%, STZ 53±11% P=0.89) in both groups of animals. (arvojournals.org)
  • Hypercapnia normally triggers a reflex which increases breathing and access to oxygen, such as arousal and turning the head during sleep. (apneaboard.com)
  • Hypercapnia, as well as hypoxia, increases RBF, as shown in previous studies using various methods in various species. (arvojournals.org)
  • Hypercapnia did not affect whole animal oxygen consumption over a period of 4 days. (physiology.org)
  • Comparison of hypercapnia-based calibration techniques for measurement of cerebral oxygen metabolism with MRI. (ox.ac.uk)
  • Sleep apnea can cause hypercapnia as you are not breathing properly while sleeping, which can result in low oxygen levels and high levels of CO2. (1stclassmed.com)
  • Non-chemosensitive parafacial neurons simultaneously regulate active expiration and airway patency under hypercapnia in rats. (pubfacts.com)
  • Hypercapnia or parafacial respiratory group (pFRG) disinhibition at normocapnia evokes active expiration in rats by recruitment of pFRG late-expiratory (late-E) neurons. (pubfacts.com)
  • When hypercapnia occurs, in general, it can result from excess CO2 production or reduced CO2 exhalation from the lungs. (verywellhealth.com)
  • Hypercapnia combined with hypoxia resulted in a significant increase in renin activity, angiotensin II, and aldosterone. (ahajournals.org)
  • These findings strongly support the significant role of notoginsenoside R1 in the inhibition of hypoxia-hypercapnia-induced vasoconstriction. (greenmedinfo.com)
  • These findings suggest the presence of relative vasoconstriction in glaucoma patients, which is at least partially reversed by hypercapnia. (bmj.com)
  • J96.12 is a billable ICD code used to specify a diagnosis of chronic respiratory failure with hypercapnia. (icd.codes)
  • citation needed] Normal respiration in divers results in alveolar hypoventilation resulting in inadequate CO2 elimination or hypercapnia. (wikipedia.org)
  • Normal respiration in divers results in alveolar hypoventilation resulting in inadequate CO 2 elimination or hypercapnia. (wikidoc.org)
  • Arterial perfusion pressure was found to be relatively lower in hypercapnia than in normocapnia, while venous pressure was higher in hypercapnia than normocapnia. (bmj.com)
  • 6 weeks of nocturnal NIV improves chest symptoms, exertional dyspnoea, nocturnal hypoventilation and peak exercise capacity in adult patients with stable CF with awake hypercapnia. (bmj.com)
  • To investigate the possible long-term consequences of neonatal exposure to hypoxic hypercapnia regarding learning ability, we investigated the effect of neonatal hypoxic hypercapnia on later functions in the hippocampus. (nii.ac.jp)