Clinical manifestation consisting of a deficiency of carbon dioxide in arterial blood.
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 colorless, odorless gas that can be formed by the body and is necessary for the respiration cycle of plants and animals.
A state due to excess loss of carbon dioxide from the body. (Dorland, 27th ed)
A clinical manifestation of abnormal increase in the amount of carbon dioxide in arterial blood.
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)
The circulation of blood through the BLOOD VESSELS of the BRAIN.
Pressure within the cranial cavity. It is influenced by brain mass, the circulatory system, CSF dynamics, and skull rigidity.
A transient absence of spontaneous respiration.
Nitrogen oxide (N2O). A colorless, odorless gas that is used as an anesthetic and analgesic. High concentrations cause a narcotic effect and may replace oxygen, causing death by asphyxia. It is also used as a food aerosol in the preparation of whipping cream.
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).
Procedure in which arterial blood pressure is intentionally reduced in order to control blood loss during surgery. This procedure is performed either pharmacologically or by pre-surgical removal of blood.
Measurement of oxygen and carbon dioxide in the blood.
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 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.
An abnormal increase in the amount of oxygen in the tissues and organs.
The total volume of gas inspired or expired per unit of time, usually measured in liters per minute.
A value equal to the total volume flow divided by the cross-sectional area of the vascular bed.
Relatively complete absence of oxygen in one or more tissues.
A strong corrosive acid that is commonly used as a laboratory reagent. It is formed by dissolving hydrogen chloride in water. GASTRIC ACID is the hydrochloric acid component of GASTRIC JUICE.
The domestic dog, Canis familiaris, comprising about 400 breeds, of the carnivore family CANIDAE. They are worldwide in distribution and live in association with people. (Walker's Mammals of the World, 5th ed, p1065)
The volume of air inspired or expired during each normal, quiet respiratory cycle. Common abbreviations are TV or V with subscript T.
A vertical distance measured from a known level on the surface of a planet or other celestial body.
A stable, non-explosive inhalation anesthetic, relatively free from significant side effects.
Respiratory retention of carbon dioxide. It may be chronic or acute.
A nicotinic antagonist that has been used as a ganglionic blocker in hypertension, as an adjunct to anesthesia, and to induce hypotension during surgery.
A clinical syndrome characterized by palpitation, SHORTNESS OF BREATH, labored breathing, subjective complaints of effort and discomfort, all following slight PHYSICAL EXERTION. Other symptoms may be DIZZINESS, tremulousness, SWEATING, and INSOMNIA. Neurocirculatory asthenia is most typically seen as a form of anxiety disorder.
The arterial blood vessels supplying the CEREBRUM.
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.
A watery fluid that is continuously produced in the CHOROID PLEXUS and circulates around the surface of the BRAIN; SPINAL CORD; and in the CEREBRAL VENTRICLES.
Volume of circulating BLOOD. It is the sum of the PLASMA VOLUME and ERYTHROCYTE VOLUME.
PRESSURE of the BLOOD on the ARTERIES and other BLOOD VESSELS.
The largest of the cerebral arteries. It trifurcates into temporal, frontal, and parietal branches supplying blood to most of the parenchyma of these lobes in the CEREBRAL CORTEX. These are the areas involved in motor, sensory, and speech activities.
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.
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.
Anesthesia caused by the breathing of anesthetic gases or vapors or by insufflating anesthetic gases or vapors into the respiratory tract.
A non-invasive technique using ultrasound for the measurement of cerebrovascular hemodynamics, particularly cerebral blood flow velocity and cerebral collateral flow. With a high-intensity, low-frequency pulse probe, the intracranial arteries may be studied transtemporally, transorbitally, or from below the foramen magnum.
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.
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).
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.
That part of the RESPIRATORY TRACT or the air within the respiratory tract that does not exchange OXYGEN and CARBON DIOXIDE with pulmonary capillary blood.
A nonflammable, halogenated, hydrocarbon anesthetic that provides relatively rapid induction with little or no excitement. Analgesia may not be adequate. NITROUS OXIDE is often given concomitantly. Because halothane may not produce sufficient muscle relaxation, supplemental neuromuscular blocking agents may be required. (From AMA Drug Evaluations Annual, 1994, p178)
Physiologically, the opposition to flow of air caused by the forces of friction. As a part of pulmonary function testing, it is the ratio of driving pressure to the rate of air flow.
Substances that dissociate into two or more ions, to some extent, in water. Solutions of electrolytes thus conduct an electric current and can be decomposed by it (ELECTROLYSIS). (Grant & Hackh's Chemical Dictionary, 5th ed)
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.
Space between the dura mater and the walls of the vertebral canal.
The ratio of alveolar ventilation to simultaneous alveolar capillary blood flow in any part of the lung. (Stedman, 25th ed)
The part of CENTRAL NERVOUS SYSTEM that is contained within the skull (CRANIUM). Arising from the NEURAL TUBE, the embryonic brain is comprised of three major parts including PROSENCEPHALON (the forebrain); MESENCEPHALON (the midbrain); and RHOMBENCEPHALON (the hindbrain). The developed brain consists of CEREBRUM; CEREBELLUM; and other structures in the BRAIN STEM.
A disorder characterized by recurrent apneas during sleep despite persistent respiratory efforts. It is due to upper airway obstruction. The respiratory pauses may induce HYPERCAPNIA or HYPOXIA. Cardiac arrhythmias and elevation of systemic and pulmonary arterial pressures may occur. Frequent partial arousals occur throughout sleep, resulting in relative SLEEP DEPRIVATION and daytime tiredness. Associated conditions include OBESITY; ACROMEGALY; MYXEDEMA; micrognathia; MYOTONIC DYSTROPHY; adenotonsilar dystrophy; and NEUROMUSCULAR DISEASES. (From Adams et al., Principles of Neurology, 6th ed, p395)
Simultaneous and continuous monitoring of several parameters during sleep to study normal and abnormal sleep. The study includes monitoring of brain waves, to assess sleep stages, and other physiological variables such as breathing, eye movements, and blood oxygen levels which exhibit a disrupted pattern with sleep disturbances.
Disorders characterized by multiple cessations of respirations during sleep that induce partial arousals and interfere with the maintenance of sleep. Sleep apnea syndromes are divided into central (see SLEEP APNEA, CENTRAL), obstructive (see SLEEP APNEA, OBSTRUCTIVE), and mixed central-obstructive types.
A readily reversible suspension of sensorimotor interaction with the environment, usually associated with recumbency and immobility.
A technique of respiratory therapy, in either spontaneously breathing or mechanically ventilated patients, in which airway pressure is maintained above atmospheric pressure throughout the respiratory cycle by pressurization of the ventilatory circuit. (On-Line Medical Dictionary [Internet]. Newcastle upon Tyne(UK): The University Dept. of Medical Oncology: The CancerWEB Project; c1997-2003 [cited 2003 Apr 17]. Available from: http://cancerweb.ncl.ac.uk/omd/)
Rough, noisy breathing during sleep, due to vibration of the uvula and soft palate.
Conditions characterized by disturbances of usual sleep patterns or behaviors. Sleep disorders may be divided into three major categories: DYSSOMNIAS (i.e. disorders characterized by insomnia or hypersomnia), PARASOMNIAS (abnormal sleep behaviors), and sleep disorders secondary to medical or psychiatric disorders. (From Thorpy, Sleep Disorders Medicine, 1994, p187)

Blockade of ATP-sensitive potassium channels in cerebral arterioles inhibits vasoconstriction from hypocapnic alkalosis in cats. (1/170)

BACKGROUND AND PURPOSE: Recent studies have shown that the cerebral arteriolar dilation from hypercapnic acidosis is blocked by agents which inhibit KATP channels. These findings suggested that this response is due to opening of KATP channels. Because the repose to CO2 is a continuum, with hypercapnic acidosis causing vasodilation and hypocapnic alkalosis causing vasoconstriction, it would be expected that the response to hypocapnic alkalosis would be due to closing of KATP channels. There are no studies of the effect of inhibition of KATP channels on the response to hypocapnic alkalosis. METHODS: We investigated the effect of 3 agents that in earlier studies were found to inhibit KATP channels--NG-nitro-L-arginine, hydroxylysine, and glyburide--on the cerebral arteriolar constriction caused by graded hypocapnia induced by hyperventilation in anesthetized cats equipped with cranial windows. RESULTS: Hypocapnic alkalosis caused dose-dependent vasoconstriction that was inhibited completely by each of the 3 inhibitors of KATP channels. The blockade induced by these agents was eliminated in the presence of topical L-lysine (5 micromol/L). CONCLUSIONS: The findings show that agents which inhibit ATP-sensitive potassium channels in cerebral arterioles inhibit the vasoconstriction from hypocapnic alkalosis. These and earlier results showing that inhibition of KATP channels inhibited dilation from hypercapnic acidosis demonstrate that the response to CO2 in cerebral arterioles is mediated by the opening and closing of KATP channels.  (+info)

Non-chemical inhibition of respiratory motor output during mechanical ventilation in sleeping humans. (2/170)

1. To determine the magnitude and time course of changes in respiratory motor output caused by non-chemical influences, six sleeping subjects underwent assist-control mechanical ventilation (ACMV) at increased tidal volume (VT). During ACMV, end-tidal PCO2 (PET,CO2) was either held at normocapnic levels (PET,CO2, 0.6-1.1 mmHg > control) by adding CO2 to the inspirate, or it was allowed to fall (hypocapnia). 2. Each sleeping subject underwent several repeat trials of twenty-five ACMV breaths (VT, 1.3 or 2.1 times control; peak flow rate, 30-40 l min-1; inspiratory time, +/- 0.3 s of control). The end-tidal to arterial PCO2 difference throughout normocapnic ACMV at raised VT was unchanged from eupnoeic levels during studies in wakefulness. 3. Normocapnic ACMV at both the smaller and larger increases in VT decreased the amplitude of respiratory motor output, as judged by decreased maximum rate of rise of mask pressure (Pm) (mean dPm/dtmax, 46-68% of control), reduced diaphragmatic EMG (to 55% of control) and reduced VT on the first spontaneous breath after ACMV (to 70% of control). Expiratory time (TE) was slightly prolonged (13-32% > control). This inhibition of amplitude of respiratory motor output progressed over the first five to seven ventilator cycles, was maintained over the remaining 18-20 cycles and persisted for three to five spontaneous breaths immediately following cessation of ACMV. 4. Hypocapnia did not further inhibit respiratory motor output amplitude beyond the effect of normocapnic ACMV at high VT, but did cause highly variable prolongation of TE when PET,CO2 was reduced by greater than 3 mmHg for at least five ventilator cycles. 5. These data in sleeping humans support the existence of a significant, non-chemical inhibitory influence of ACMV at increased VT and positive pressure upon the amplitude of respiratory motor output; this effect is manifested both during and following normocapnic mechanical ventilation.  (+info)

Effect of intravenous dipyridamole on cerebral blood flow in humans. A PET study. (3/170)

BACKGROUND AND PURPOSE: Dipyridamole increases the concentration of circulating adenosine, which is a potent vasodilator, by inhibition of uptake of adenosine into the erythrocytes, and hence produces coronary vasodilation. However, the effects of dipyridamole on cerebral circulation is not pronounced. This study investigates the effects of intravenous dipyridamole on cerebral blood flow (CBF) in humans with use of positron emission tomography (PET). METHODS: In each of 13 healthy subjects, CBF was measured using (15)O-labeled water and PET at rest and during hypercapnia, hypocapnia, and dipyridamole stress; corresponding CBF values were then compared. RESULTS: CBF values during dipyridamole stress were significantly lower than those measured at rest. The dipyridamole stress PaCO(2) was also significantly lower than the resting PaCO(2). The change in CBF during dipyridamole stress relative to PaCO(2) closely followed the relationship between CBF and PaCO(2) during hypocapnia. CONCLUSIONS: These results indicate that the observed decrease in CBF during dipyridamole stress was caused by a decrease in PaCO(2) rather than by any direct action of dipyridamole on CBF. The decrease in PaCO(2) during dipyridamole stress was most likely due to hyperventilation, which was a side effect of adenosine. These results support the hypothesis that circulating adenosine is largely prevented from binding to adenosine receptors of cerebral vessels by the blood-brain barrier.  (+info)

Splanchnic hemodynamics and gut mucosal-arterial PCO(2) gradient during systemic hypocapnia. (4/170)

The effects of hypocapnia [arterial PCO(2) (Pa(CO(2))) 15 Torr] on splanchnic hemodynamics and gut mucosal-arterial P(CO(2)) were studied in seven anesthetized ventilated dogs. Ileal mucosal and serosal blood flow were estimated by using laser Doppler flowmetry, mucosal PCO(2) was measured continuously by using capnometric recirculating gas tonometry, and serosal surface PO(2) was assessed by using a polarographic electrode. Hypocapnia was induced by removal of dead space and was maintained for 45 min, followed by 45 min of eucapnia. Mean Pa(CO(2)) at baseline was 38.1 +/- 1.1 (SE) Torr and decreased to 13.8 +/- 1.3 Torr after removal of dead space. Cardiac output and portal blood flow decreased significantly with hypocapnia. Similarly, mucosal and serosal blood flow decreased by 15 +/- 4 and by 34 +/- 7%, respectively. Also, an increase in the mucosal-arterial PCO(2) gradient of 10.7 Torr and a reduction in serosal PO(2) of 30 Torr were observed with hypocapnia (P < 0.01 for both). Hypocapnia caused ileal mucosal and serosal hypoperfusion, with redistribution of flow favoring the mucosa, accompanied by increased PCO(2) gradient and diminished serosal PO(2).  (+info)

Repetitive hyperpnoea causes peripheral airway obstruction and eosinophilia. (5/170)

Hyperpnoea of canine peripheral airways with dry air results in airway obstruction, mucosal damage, and inflammation. The purpose of this study was to evaluate the effect of repeated dry air challenge (DAC) on airway obstruction, reactivity and the development of airway inflammation in dogs. Canine peripheral airways received DAC (delivered under general anaesthesia through a bronchoscope) every 48 h for two weeks. Peripheral airway resistance and reactivity were measured prior to each DAC. After the final DAC, bronchoalveolar lavage fluid (BALF) cells and soluble mediators from challenged and control airways were measured. Repeated bronchoscopy had no effect on airway mechanics. Repeated DAC produced cumulative increases in peripheral airway resistance and peak obstructive response to DAC. The response to hypocapnia was also increased in airways receiving repeated DAC. However, when the response to agonists was expressed as a change from baseline, consistent significant increases were not observed. Repeated bronchoscopy produced insignificant changes in BALF cells and eicosanoid mediators. Repeated DAC produced marked eosinophilic inflammation and increased prostaglandins D2, E2, and F2alpha, as well as leukotrienes C4-E4. In conclusion, repeated dry air challenge in dogs in vivo causes persistent airway obstruction and inflammation not unlike that found in human asthma.  (+info)

A mechanism of central sleep apnea in patients with heart failure. (6/170)

BACKGROUND: Breathing is controlled by a negative-feedback system in which an increase in the partial pressure of arterial carbon dioxide stimulates breathing and a decrease inhibits it. Although enhanced sensitivity to carbon dioxide helps maintain the partial pressure of arterial carbon dioxide within a narrow range during waking hours, in some persons a large hyperventilatory response during sleep may lower the value below the apneic threshold, thereby resulting in central apnea. I tested the hypothesis that enhanced sensitivity to carbon dioxide contributes to the development of central sleep apnea in some patients with heart failure. METHODS: This prospective study included 20 men who had treated, stable heart failure with left ventricular systolic dysfunction. Ten had central sleep apnea, and 10 did not. The patients underwent polysomnography and studies of their ventilatory response to carbon dioxide. RESULTS: Patients who met the criteria for central sleep apnea had significantly more episodes of central apnea per hour than those without central sleep apnea (mean [+/-SD], 35+/-24 vs. 0.5+/-1.0 episodes per hour). Those with sleep apnea also had a significantly larger ventilatory response to carbon dioxide than those without central sleep apnea (5.1+/-3.1 vs. 2.1+/-1.0 liters per minute per millimeter of mercury, P=0.007), and there was a significant positive correlation between ventilatory response and the number of episodes of apnea and hypopnea per hour during sleep (r=0.6, P=0.01). CONCLUSIONS: Enhanced sensitivity to carbon dioxide may predispose some patients with heart failure to the development of central sleep apnea.  (+info)

Impeding O(2) unloading in muscle delays oxygen uptake response to exercise onset in humans. (7/170)

We tested whether the leftward shift of the oxygen dissociation curve of hemoglobin with hyperpnea delays the oxygen uptake (VO(2)) response to the onset of exercise. Six male subjects performed cycle ergometer exercise at a work rate corresponding to 80% of the ventilatory threshold (VT) VO(2) of each individual after 3 min of 20-W cycling under eupnea [control (Con) trial]. A hyperpnea procedure (minute ventilation = 60 l/min) was undertaken for 2 min before and during 80% VT exercise in hypocapnia (Hypo) and normocapnia (Normo) trials. In the Normo trial, the inspired CO(2) fraction was 3% to prevent hypocapnia. The subjects completed two repetitions of each trial. To determine the kinetic variables of VO(2) and heart rate (HR) at the onset of exercise, a nonlinear least-squares fitting was applied to the data averaged from two repetitions by a monoexponential model. The end-tidal CO(2) partial pressure before the onset of exercise was significantly lower in the Hypo trial than in the Con and Normo trials (22 +/- 1 vs. 38 +/- 3 and 36 +/- 1 mmHg, respectively, P < 0.05). The time constant of VO(2) and HR was significantly longer in the Normo trial (28 +/- 7 and 39 +/- 18 s, respectively) than in the Con trial (21 +/- 7, 34 +/- 16 s, respectively, P < 0.05). The VO(2) time constant of the Hypo trial (37 +/- 12 s) was significantly longer than that of the Normo trial, although no significant difference in the HR time constant was seen (Hypo, 41 +/- 28 s). These findings suggested that respiratory alkalosis delayed the kinetics of oxygen diffusion in active muscle as a result of the leftward shift of the oxygen dissociation curve of hemoglobin. This supports an important role for hemoglobin-O(2) offloading in setting the VO(2) kinetics at exercise onset.  (+info)

Diuretic effect of hypoxia, hypocapnia, and hyperpnea in humans: relation to hormones and O(2) chemosensitivity. (8/170)

We studied the contributions of hypoxemia, hypocapnia, and hyperpnea to the acute hypoxic diuretic response (HDR) in humans and evaluated the role of peripheral O(2) chemosensitivity and renal hormones in HDR. Thirteen healthy male subjects (age 19-38 yr) were examined after sodium equilibration (intake: 120 mmol/day) during 90 min of normoxia (NO), poikilocapnic hypoxia (PH), and isocapnic hypoxia (IH) (days 1-3, random order, double blind), as well as normoxic voluntary hyperpnea (HP; day 4), matching ventilation during IH. O(2) saturation during PH and IH was kept equal to a mean level measured between 30 and 90 min of breathing 12% O(2) in a pretest. Urine flow during PH and IH (1.81 +/- 0.92 and 1.94 +/- 1.03 ml/min, respectively) but not during HP (1.64 +/- 0.96 ml/min) significantly exceeded that during NO (control, 1.38 +/- 0.71 ml/min). Urine flow increases vs. each test day's baseline were significant with PH, IH, and HP. Differences in glomerular filtration rate, fractional sodium clearance, urodilatin, systemic blood pressure, or leg venous compliance were excluded as factors of HDR. However, slight increases in plasma and urinary endothelin-1 and epinephrine with PH and IH could play a role. In conclusion, the early HDR in humans is mainly due to hypoxia and hypocapnia. It occurs without natriuresis and is unrelated to O(2) chemosensitivity (hypoxic ventilatory response).  (+info)

Hypocapnia is a medical term that refers to a condition where there is an abnormally low level of carbon dioxide (CO2) in the blood. Carbon dioxide is a gas that is produced by the body's cells as they carry out their normal metabolic processes, and it is transported in the bloodstream to the lungs, where it is exhaled out of the body during breathing.

Hypocapnia can occur when a person breathes too quickly or too deeply, which can cause too much CO2 to be exhaled from the body. This condition can also result from certain medical conditions that affect breathing, such as chronic obstructive pulmonary disease (COPD), asthma, and sleep apnea.

Mild hypocapnia may not cause any noticeable symptoms, but more severe cases can lead to symptoms such as dizziness, lightheadedness, headache, confusion, and rapid breathing. In extreme cases, it can lead to life-threatening conditions such as respiratory failure or cardiac arrest.

Hypocapnia is typically diagnosed through blood tests that measure the level of CO2 in the blood. Treatment for hypocapnia may involve addressing any underlying medical conditions that are causing it, as well as providing supportive care to help the person breathe more effectively.

Hyperventilation is a medical condition characterized by an increased respiratory rate and depth, resulting in excessive elimination of carbon dioxide (CO2) from the body. This leads to hypocapnia (low CO2 levels in the blood), which can cause symptoms such as lightheadedness, dizziness, confusion, tingling sensations in the extremities, and muscle spasms. Hyperventilation may occur due to various underlying causes, including anxiety disorders, lung diseases, neurological conditions, or certain medications. It is essential to identify and address the underlying cause of hyperventilation for proper treatment.

Carbon dioxide (CO2) is a colorless, odorless gas that is naturally present in the Earth's atmosphere. It is a normal byproduct of cellular respiration in humans, animals, and plants, and is also produced through the combustion of fossil fuels such as coal, oil, and natural gas.

In medical terms, carbon dioxide is often used as a respiratory stimulant and to maintain the pH balance of blood. It is also used during certain medical procedures, such as laparoscopic surgery, to insufflate (inflate) the abdominal cavity and create a working space for the surgeon.

Elevated levels of carbon dioxide in the body can lead to respiratory acidosis, a condition characterized by an increased concentration of carbon dioxide in the blood and a decrease in pH. This can occur in conditions such as chronic obstructive pulmonary disease (COPD), asthma, or other lung diseases that impair breathing and gas exchange. Symptoms of respiratory acidosis may include shortness of breath, confusion, headache, and in severe cases, coma or death.

Respiratory alkalosis is a medical condition that occurs when there is an excess base (bicarbonate) and/or a decrease in carbon dioxide in the body. This leads to an increase in pH level of the blood, making it more alkaline than normal. Respiratory alkalosis is usually caused by conditions that result in hyperventilation, such as anxiety, lung disease, or high altitude. It can also be caused by certain medications and medical procedures. Symptoms of respiratory alkalosis may include lightheadedness, confusion, and tingling in the fingers and toes. Treatment typically involves addressing the underlying cause of the condition.

Hypercapnia is a state of increased carbon dioxide (CO2) concentration in the blood, typically defined as an arterial CO2 tension (PaCO2) above 45 mmHg. It is often associated with conditions that impair gas exchange or eliminate CO2 from the body, such as chronic obstructive pulmonary disease (COPD), severe asthma, respiratory failure, or certain neuromuscular disorders. Hypercapnia can cause symptoms such as headache, confusion, shortness of breath, and in severe cases, it can lead to life-threatening complications such as respiratory acidosis, coma, and even death if not promptly treated.

In the context of medicine, and specifically in physiology and respiratory therapy, partial pressure (P or p) is a measure of the pressure exerted by an individual gas in a mixture of gases. It's commonly used to describe the concentrations of gases in the body, such as oxygen (PO2), carbon dioxide (PCO2), and nitrogen (PN2).

The partial pressure of a specific gas is calculated as the fraction of that gas in the total mixture multiplied by the total pressure of the mixture. This concept is based on Dalton's law, which states that the total pressure exerted by a mixture of gases is equal to the sum of the pressures exerted by each individual gas.

For example, in room air at sea level, the partial pressure of oxygen (PO2) is approximately 160 mmHg (mm of mercury), which represents about 21% of the total barometric pressure (760 mmHg). This concept is crucial for understanding gas exchange in the lungs and how gases move across membranes, such as from alveoli to blood and vice versa.

Cerebrovascular circulation refers to the network of blood vessels that supply oxygenated blood and nutrients to the brain tissue, and remove waste products. It includes the internal carotid arteries, vertebral arteries, circle of Willis, and the intracranial arteries that branch off from them.

The internal carotid arteries and vertebral arteries merge to form the circle of Willis, a polygonal network of vessels located at the base of the brain. The anterior cerebral artery, middle cerebral artery, posterior cerebral artery, and communicating arteries are the major vessels that branch off from the circle of Willis and supply blood to different regions of the brain.

Interruptions or abnormalities in the cerebrovascular circulation can lead to various neurological conditions such as stroke, transient ischemic attack (TIA), and vascular dementia.

Intracranial pressure (ICP) is the pressure inside the skull and is typically measured in millimeters of mercury (mmHg). It's the measurement of the pressure exerted by the cerebrospinal fluid (CSF), blood, and brain tissue within the confined space of the skull.

Normal ICP ranges from 5 to 15 mmHg in adults when lying down. Intracranial pressure may increase due to various reasons such as bleeding in the brain, swelling of the brain, increased production or decreased absorption of CSF, and brain tumors. Elevated ICP is a serious medical emergency that can lead to brain damage or even death if not promptly treated. Symptoms of high ICP may include severe headache, vomiting, altered consciousness, and visual changes.

Apnea is a medical condition defined as the cessation of breathing for 10 seconds or more. It can occur during sleep (sleep apnea) or while awake (wakeful apnea). There are different types of sleep apnea, including obstructive sleep apnea, central sleep apnea, and complex sleep apnea syndrome. Obstructive sleep apnea occurs when the airway becomes blocked during sleep, while central sleep apnea occurs when the brain fails to signal the muscles to breathe. Complex sleep apnea syndrome, also known as treatment-emergent central sleep apnea, is a combination of obstructive and central sleep apneas. Sleep apnea can lead to various complications, such as fatigue, difficulty concentrating, high blood pressure, heart disease, and stroke.

Nitrous oxide, also known as laughing gas, is a colorless and non-flammable gas with a slightly sweet odor and taste. In medicine, it's commonly used for its anesthetic and pain reducing effects. It is often used in dental procedures, surgery, and childbirth to help reduce anxiety and provide mild sedation. Nitrous oxide works by binding to the hemoglobin in red blood cells, which reduces the oxygen-carrying capacity of the blood, but this effect is usually not significant at the low concentrations used for analgesia and anxiolysis. It's also considered relatively safe when administered by a trained medical professional because it does not cause depression of the respiratory system or cardiovascular function.

Medical Definition of Respiration:

Respiration, in physiology, is the process by which an organism takes in oxygen and gives out carbon dioxide. It's also known as breathing. This process is essential for most forms of life because it provides the necessary oxygen for cellular respiration, where the cells convert biochemical energy from nutrients into adenosine triphosphate (ATP), and releases waste products, primarily carbon dioxide.

In humans and other mammals, respiration is a two-stage process:

1. Breathing (or external respiration): This involves the exchange of gases with the environment. Air enters the lungs through the mouth or nose, then passes through the pharynx, larynx, trachea, and bronchi, finally reaching the alveoli where the actual gas exchange occurs. Oxygen from the inhaled air diffuses into the blood, while carbon dioxide, a waste product of metabolism, diffuses from the blood into the alveoli to be exhaled.

2. Cellular respiration (or internal respiration): This is the process by which cells convert glucose and other nutrients into ATP, water, and carbon dioxide in the presence of oxygen. The carbon dioxide produced during this process then diffuses out of the cells and into the bloodstream to be exhaled during breathing.

In summary, respiration is a vital physiological function that enables organisms to obtain the necessary oxygen for cellular metabolism while eliminating waste products like carbon dioxide.

Controlled hypotension is a medical procedure in which the healthcare provider intentionally lowers the patient's blood pressure during surgery. This is done to reduce bleeding and improve surgical conditions. The goal is to maintain the patient's blood pressure at a level that is lower than their normal resting blood pressure, but high enough to ensure adequate blood flow to vital organs such as the heart and brain. Controlled hypotension is closely monitored and managed throughout the surgery to minimize risks and ensure the best possible outcomes for the patient.

Blood gas analysis is a medical test that measures the levels of oxygen and carbon dioxide in the blood, as well as the pH level, which indicates the acidity or alkalinity of the blood. This test is often used to evaluate lung function, respiratory disorders, and acid-base balance in the body. It can also be used to monitor the effectiveness of treatments for conditions such as chronic obstructive pulmonary disease (COPD), asthma, and other respiratory illnesses. The analysis is typically performed on a sample of arterial blood, although venous blood may also be used in some cases.

Oxygen is a colorless, odorless, tasteless gas that constitutes about 21% of the earth's atmosphere. It is a crucial element for human and most living organisms as it is vital for respiration. Inhaled oxygen enters the lungs and binds to hemoglobin in red blood cells, which carries it to tissues throughout the body where it is used to convert nutrients into energy and carbon dioxide, a waste product that is exhaled.

Medically, supplemental oxygen therapy may be provided to patients with conditions such as chronic obstructive pulmonary disease (COPD), pneumonia, heart failure, or other medical conditions that impair the body's ability to extract sufficient oxygen from the air. Oxygen can be administered through various devices, including nasal cannulas, face masks, and ventilators.

Acid-base equilibrium refers to the balance between the concentration of acids and bases in a solution, which determines its pH level. In a healthy human body, maintaining acid-base equilibrium is crucial for proper cellular function and homeostasis.

The balance is maintained by several buffering systems in the body, including the bicarbonate buffer system, which helps to regulate the pH of blood. This system involves the reaction between carbonic acid (a weak acid) and bicarbonate ions (a base) to form water and carbon dioxide.

The balance between acids and bases is carefully regulated by the body's respiratory and renal systems. The lungs control the elimination of carbon dioxide, a weak acid, through exhalation, while the kidneys regulate the excretion of hydrogen ions and the reabsorption of bicarbonate ions.

When the balance between acids and bases is disrupted, it can lead to acid-base disorders such as acidosis (excessive acidity) or alkalosis (excessive basicity). These conditions can have serious consequences on various organ systems if left untreated.

Hyperoxia is a medical term that refers to an abnormally high concentration of oxygen in the body or in a specific organ or tissue. It is often defined as the partial pressure of oxygen (PaO2) in arterial blood being greater than 100 mmHg.

This condition can occur due to various reasons such as exposure to high concentrations of oxygen during medical treatments, like mechanical ventilation, or due to certain diseases and conditions that cause the body to produce too much oxygen.

While oxygen is essential for human life, excessive levels can be harmful and lead to oxidative stress, which can damage cells and tissues. Hyperoxia has been linked to various complications, including lung injury, retinopathy of prematurity, and impaired wound healing.

Pulmonary ventilation, also known as pulmonary respiration or simply ventilation, is the process of moving air into and out of the lungs to facilitate gas exchange. It involves two main phases: inhalation (or inspiration) and exhalation (or expiration). During inhalation, the diaphragm and external intercostal muscles contract, causing the chest volume to increase and the pressure inside the chest to decrease, which then draws air into the lungs. Conversely, during exhalation, these muscles relax, causing the chest volume to decrease and the pressure inside the chest to increase, which pushes air out of the lungs. This process ensures that oxygen-rich air from the atmosphere enters the alveoli (air sacs in the lungs), where it can diffuse into the bloodstream, while carbon dioxide-rich air from the bloodstream in the capillaries surrounding the alveoli is expelled out of the body.

Blood flow velocity is the speed at which blood travels through a specific part of the vascular system. It is typically measured in units of distance per time, such as centimeters per second (cm/s) or meters per second (m/s). Blood flow velocity can be affected by various factors, including cardiac output, vessel diameter, and viscosity of the blood. Measuring blood flow velocity is important in diagnosing and monitoring various medical conditions, such as heart disease, stroke, and peripheral vascular disease.

Anoxia is a medical condition that refers to the absence or complete lack of oxygen supply in the body or a specific organ, tissue, or cell. This can lead to serious health consequences, including damage or death of cells and tissues, due to the vital role that oxygen plays in supporting cellular metabolism and energy production.

Anoxia can occur due to various reasons, such as respiratory failure, cardiac arrest, severe blood loss, carbon monoxide poisoning, or high altitude exposure. Prolonged anoxia can result in hypoxic-ischemic encephalopathy, a serious condition that can cause brain damage and long-term neurological impairments.

Medical professionals use various diagnostic tests, such as blood gas analysis, pulse oximetry, and electroencephalography (EEG), to assess oxygen levels in the body and diagnose anoxia. Treatment for anoxia typically involves addressing the underlying cause, providing supplemental oxygen, and supporting vital functions, such as breathing and circulation, to prevent further damage.

Hydrochloric acid, also known as muriatic acid, is not a substance that is typically found within the human body. It is a strong mineral acid with the chemical formula HCl. In a medical context, it might be mentioned in relation to gastric acid, which helps digest food in the stomach. Gastric acid is composed of hydrochloric acid, potassium chloride and sodium chloride dissolved in water. The pH of hydrochloric acid is very low (1-2) due to its high concentration of H+ ions, making it a strong acid. However, it's important to note that the term 'hydrochloric acid' does not directly refer to a component of human bodily fluids or tissues.

I believe there might be a misunderstanding in your question. "Dogs" is not a medical term or condition. It is the common name for a domesticated carnivore of the family Canidae, specifically the genus Canis, which includes wolves, foxes, and other extant and extinct species of mammals. Dogs are often kept as pets and companions, and they have been bred in a wide variety of forms and sizes for different purposes, such as hunting, herding, guarding, assisting police and military forces, and providing companionship and emotional support.

If you meant to ask about a specific medical condition or term related to dogs, please provide more context so I can give you an accurate answer.

Tidal volume (Vt) is the amount of air that moves into or out of the lungs during normal, resting breathing. It is the difference between the volume of air in the lungs at the end of a normal expiration and the volume at the end of a normal inspiration. In other words, it's the volume of each breath you take when you are not making any effort to breathe more deeply.

The average tidal volume for an adult human is around 500 milliliters (ml) per breath, but this can vary depending on factors such as age, sex, size, and fitness level. During exercise or other activities that require increased oxygen intake, tidal volume may increase to meet the body's demands for more oxygen.

Tidal volume is an important concept in respiratory physiology and clinical medicine, as it can be used to assess lung function and diagnose respiratory disorders such as chronic obstructive pulmonary disease (COPD) or asthma.

Altitude is the height above a given level, especially mean sea level. In medical terms, altitude often refers to high altitude, which is generally considered to be 1500 meters (about 5000 feet) or more above sea level. At high altitudes, the air pressure is lower and there is less oxygen available, which can lead to altitude sickness in some people. Symptoms of altitude sickness can include headache, dizziness, shortness of breath, and fatigue. It's important for people who are traveling to high altitudes to allow themselves time to adjust to the lower oxygen levels and to watch for signs of altitude sickness.

Isoflurane is a volatile halogenated ether used for induction and maintenance of general anesthesia. It is a colorless liquid with a pungent, sweet odor. Isoflurane is an agonist at the gamma-aminobutyric acid type A (GABAA) receptor and inhibits excitatory neurotransmission in the brain, leading to unconsciousness and immobility. It has a rapid onset and offset of action due to its low blood solubility, allowing for quick adjustments in anesthetic depth during surgery. Isoflurane is also known for its bronchodilator effects, making it useful in patients with reactive airway disease. However, it can cause dose-dependent decreases in heart rate and blood pressure, so careful hemodynamic monitoring is required during its use.

Respiratory acidosis is a medical condition that occurs when the lungs are not able to remove enough carbon dioxide (CO2) from the body, leading to an increase in the amount of CO2 in the bloodstream and a decrease in the pH of the blood. This can happen due to various reasons such as chronic lung diseases like emphysema or COPD, severe asthma attacks, neuromuscular disorders that affect breathing, or when someone is not breathing deeply or frequently enough, such as during sleep apnea or drug overdose.

Respiratory acidosis can cause symptoms such as headache, confusion, shortness of breath, and in severe cases, coma and even death. Treatment for respiratory acidosis depends on the underlying cause but may include oxygen therapy, bronchodilators, or mechanical ventilation to help support breathing.

Trimethaphan is a ganglionic blocker drug that is used primarily in the treatment of hypertensive emergencies. It works by blocking the transmission of nerve impulses at the ganglionic synapse, leading to decreased sympathetic and parasympathetic tone. This results in a decrease in peripheral vascular resistance, heart rate, and blood pressure.

Trimethaphan is administered intravenously and its effects are rapid in onset but also short-lived, typically lasting only 5-10 minutes after discontinuation of the infusion. It is therefore necessary to continuously monitor blood pressure during administration and adjust the dose as needed to maintain a stable blood pressure.

Common side effects of trimethaphan include flushing, diaphoresis, dizziness, headache, and blurred vision. More serious side effects can include bronchospasm, myocardial ischemia, and anaphylaxis. Trimethaphan should be used with caution in patients with preexisting respiratory or cardiovascular disease.

Neurocirculatory asthenia is not a term that is widely used in modern medicine. However, historically, it has been used as a descriptive diagnosis for a group of symptoms characterized by fatigue, weakness, dizziness, and disturbances of heart rate and blood pressure, often in response to emotional stress or physical exertion.

The term "neurocirculatory" refers to the interaction between the nervous system and the cardiovascular system, while "asthenia" is a general term used to describe a lack of energy or weakness.

In modern medicine, this condition may be diagnosed as a form of functional disorder, neurasthenia, or somatic symptom disorder, depending on the specific symptoms and underlying causes. It's important to note that while these symptoms can be real and debilitating, they do not have a clear organic cause, and treatment typically focuses on managing symptoms and addressing any underlying psychological or emotional factors.

Cerebral arteries refer to the blood vessels that supply oxygenated blood to the brain. These arteries branch off from the internal carotid arteries and the vertebral arteries, which combine to form the basilar artery. The major cerebral arteries include:

1. Anterior cerebral artery (ACA): This artery supplies blood to the frontal lobes of the brain, including the motor and sensory cortices responsible for movement and sensation in the lower limbs.
2. Middle cerebral artery (MCA): The MCA is the largest of the cerebral arteries and supplies blood to the lateral surface of the brain, including the temporal, parietal, and frontal lobes. It is responsible for providing blood to areas involved in motor function, sensory perception, speech, memory, and vision.
3. Posterior cerebral artery (PCA): The PCA supplies blood to the occipital lobe, which is responsible for visual processing, as well as parts of the temporal and parietal lobes.
4. Anterior communicating artery (ACoA) and posterior communicating arteries (PComAs): These are small arteries that connect the major cerebral arteries, forming an important circulatory network called the Circle of Willis. The ACoA connects the two ACAs, while the PComAs connect the ICA with the PCA and the basilar artery.

These cerebral arteries play a crucial role in maintaining proper brain function by delivering oxygenated blood to various regions of the brain. Any damage or obstruction to these arteries can lead to serious neurological conditions, such as strokes or transient ischemic attacks (TIAs).

Acidosis is a medical condition that occurs when there is an excess accumulation of acid in the body or when the body loses its ability to effectively regulate the pH level of the blood. The normal pH range of the blood is slightly alkaline, between 7.35 and 7.45. When the pH falls below 7.35, it is called acidosis.

Acidosis can be caused by various factors, including impaired kidney function, respiratory problems, diabetes, severe dehydration, alcoholism, and certain medications or toxins. There are two main types of acidosis: metabolic acidosis and respiratory acidosis.

Metabolic acidosis occurs when the body produces too much acid or is unable to eliminate it effectively. This can be caused by conditions such as diabetic ketoacidosis, lactic acidosis, kidney failure, and ingestion of certain toxins.

Respiratory acidosis, on the other hand, occurs when the lungs are unable to remove enough carbon dioxide from the body, leading to an accumulation of acid. This can be caused by conditions such as chronic obstructive pulmonary disease (COPD), asthma, and sedative overdose.

Symptoms of acidosis may include fatigue, shortness of breath, confusion, headache, rapid heartbeat, and in severe cases, coma or even death. Treatment for acidosis depends on the underlying cause and may include medications, oxygen therapy, fluid replacement, and dialysis.

Cerebrospinal fluid (CSF) is a clear, colorless fluid that surrounds and protects the brain and spinal cord. It acts as a shock absorber for the central nervous system and provides nutrients to the brain while removing waste products. CSF is produced by specialized cells called ependymal cells in the choroid plexus of the ventricles (fluid-filled spaces) inside the brain. From there, it circulates through the ventricular system and around the outside of the brain and spinal cord before being absorbed back into the bloodstream. CSF analysis is an important diagnostic tool for various neurological conditions, including infections, inflammation, and cancer.

Blood volume refers to the total amount of blood present in an individual's circulatory system at any given time. It is the combined volume of both the plasma (the liquid component of blood) and the formed elements (such as red and white blood cells and platelets) in the blood. In a healthy adult human, the average blood volume is approximately 5 liters (or about 1 gallon). However, blood volume can vary depending on several factors, including age, sex, body weight, and overall health status.

Blood volume plays a critical role in maintaining proper cardiovascular function, as it affects blood pressure, heart rate, and the delivery of oxygen and nutrients to tissues throughout the body. Changes in blood volume can have significant impacts on an individual's health and may be associated with various medical conditions, such as dehydration, hemorrhage, heart failure, and liver disease. Accurate measurement of blood volume is essential for diagnosing and managing these conditions, as well as for guiding treatment decisions in clinical settings.

Blood pressure is the force exerted by circulating blood on the walls of the blood vessels. It is measured in millimeters of mercury (mmHg) and is given as two figures:

1. Systolic pressure: This is the pressure when the heart pushes blood out into the arteries.
2. Diastolic pressure: This is the pressure when the heart rests between beats, allowing it to fill with blood.

Normal blood pressure for adults is typically around 120/80 mmHg, although this can vary slightly depending on age, sex, and other factors. High blood pressure (hypertension) is generally considered to be a reading of 130/80 mmHg or higher, while low blood pressure (hypotension) is usually defined as a reading below 90/60 mmHg. It's important to note that blood pressure can fluctuate throughout the day and may be affected by factors such as stress, physical activity, and medication use.

The Middle Cerebral Artery (MCA) is one of the main blood vessels that supplies oxygenated blood to the brain. It arises from the internal carotid artery and divides into several branches, which supply the lateral surface of the cerebral hemisphere, including the frontal, parietal, and temporal lobes.

The MCA is responsible for providing blood flow to critical areas of the brain, such as the primary motor and sensory cortices, Broca's area (associated with speech production), Wernicke's area (associated with language comprehension), and the visual association cortex.

Damage to the MCA or its branches can result in a variety of neurological deficits, depending on the specific location and extent of the injury. These may include weakness or paralysis on one side of the body, sensory loss, language impairment, and visual field cuts.

Respiratory mechanics refers to the biomechanical properties and processes that involve the movement of air through the respiratory system during breathing. It encompasses the mechanical behavior of the lungs, chest wall, and the muscles of respiration, including the diaphragm and intercostal muscles.

Respiratory mechanics includes several key components:

1. **Compliance**: The ability of the lungs and chest wall to expand and recoil during breathing. High compliance means that the structures can easily expand and recoil, while low compliance indicates greater resistance to expansion and recoil.
2. **Resistance**: The opposition to airflow within the respiratory system, primarily due to the friction between the air and the airway walls. Airway resistance is influenced by factors such as airway diameter, length, and the viscosity of the air.
3. **Lung volumes and capacities**: These are the amounts of air present in the lungs during different phases of the breathing cycle. They include tidal volume (the amount of air inspired or expired during normal breathing), inspiratory reserve volume (additional air that can be inspired beyond the tidal volume), expiratory reserve volume (additional air that can be exhaled beyond the tidal volume), and residual volume (the air remaining in the lungs after a forced maximum exhalation).
4. **Work of breathing**: The energy required to overcome the resistance and elastic forces during breathing. This work is primarily performed by the respiratory muscles, which contract to generate negative intrathoracic pressure and expand the chest wall, allowing air to flow into the lungs.
5. **Pressure-volume relationships**: These describe how changes in lung volume are associated with changes in pressure within the respiratory system. Important pressure components include alveolar pressure (the pressure inside the alveoli), pleural pressure (the pressure between the lungs and the chest wall), and transpulmonary pressure (the difference between alveolar and pleural pressures).

Understanding respiratory mechanics is crucial for diagnosing and managing various respiratory disorders, such as chronic obstructive pulmonary disease (COPD), asthma, and restrictive lung diseases.

Bicarbonates, also known as sodium bicarbonate or baking soda, is a chemical compound with the formula NaHCO3. In the context of medical definitions, bicarbonates refer to the bicarbonate ion (HCO3-), which is an important buffer in the body that helps maintain normal pH levels in blood and other bodily fluids.

The balance of bicarbonate and carbonic acid in the body helps regulate the acidity or alkalinity of the blood, a condition known as pH balance. Bicarbonates are produced by the body and are also found in some foods and drinking water. They work to neutralize excess acid in the body and help maintain the normal pH range of 7.35 to 7.45.

In medical testing, bicarbonate levels may be measured as part of an electrolyte panel or as a component of arterial blood gas (ABG) analysis. Low bicarbonate levels can indicate metabolic acidosis, while high levels can indicate metabolic alkalosis. Both conditions can have serious consequences if not treated promptly and appropriately.

Inhalational anesthesia is a type of general anesthesia that is induced by the inhalation of gases or vapors. It is administered through a breathing system, which delivers the anesthetic agents to the patient via a face mask, laryngeal mask airway, or endotracheal tube.

The most commonly used inhalational anesthetics include nitrous oxide, sevoflurane, isoflurane, and desflurane. These agents work by depressing the central nervous system, causing a reversible loss of consciousness, amnesia, analgesia, and muscle relaxation.

The depth of anesthesia can be easily adjusted during the procedure by changing the concentration of the anesthetic agent. Once the procedure is complete, the anesthetic agents are eliminated from the body through exhalation, allowing for a rapid recovery.

Inhalational anesthesia is commonly used in a wide range of surgical procedures due to its ease of administration, quick onset and offset of action, and ability to rapidly adjust the depth of anesthesia. However, it requires careful monitoring and management by trained anesthesia providers to ensure patient safety and optimize outcomes.

Transcranial Doppler ultrasonography is a non-invasive diagnostic technique that uses high-frequency sound waves to visualize and measure the velocity of blood flow in the cerebral arteries located in the skull. This imaging modality employs the Doppler effect, which describes the change in frequency of sound waves as they reflect off moving red blood cells. By measuring the frequency shift of the reflected ultrasound waves, the velocity and direction of blood flow can be determined.

Transcranial Doppler ultrasonography is primarily used to assess cerebrovascular circulation and detect abnormalities such as stenosis (narrowing), occlusion (blockage), or embolism (obstruction) in the intracranial arteries. It can also help monitor patients with conditions like sickle cell disease, vasospasm following subarachnoid hemorrhage, and evaluate the effectiveness of treatments such as thrombolysis or angioplasty. The procedure is typically performed by placing a transducer on the patient's skull after applying a coupling gel, and it does not involve radiation exposure or contrast agents.

Chemoreceptor cells are specialized sensory neurons that detect and respond to chemical changes in the internal or external environment. They play a crucial role in maintaining homeostasis within the body by converting chemical signals into electrical impulses, which are then transmitted to the central nervous system for further processing and response.

There are two main types of chemoreceptor cells:

1. Oxygen Chemoreceptors: These cells are located in the carotid bodies near the bifurcation of the common carotid artery and in the aortic bodies close to the aortic arch. They monitor the levels of oxygen, carbon dioxide, and pH in the blood and respond to decreases in oxygen concentration or increases in carbon dioxide and hydrogen ions (indicating acidity) by increasing their firing rate. This signals the brain to increase respiratory rate and depth, thereby restoring normal oxygen levels.

2. Taste Cells: These chemoreceptor cells are found within the taste buds of the tongue and other areas of the oral cavity. They detect specific tastes (salty, sour, sweet, bitter, and umami) by interacting with molecules from food. When a tastant binds to receptors on the surface of a taste cell, it triggers a series of intracellular signaling events that ultimately lead to the generation of an action potential. This information is then relayed to the brain, where it is interpreted as taste sensation.

In summary, chemoreceptor cells are essential for maintaining physiological balance by detecting and responding to chemical stimuli in the body. They play a critical role in regulating vital functions such as respiration and digestion.

Artificial respiration is an emergency procedure that can be used to provide oxygen to a person who is not breathing or is breathing inadequately. It involves manually forcing air into the lungs, either by compressing the chest or using a device to deliver breaths. The goal of artificial respiration is to maintain adequate oxygenation of the body's tissues and organs until the person can breathe on their own or until advanced medical care arrives. Artificial respiration may be used in conjunction with cardiopulmonary resuscitation (CPR) in cases of cardiac arrest.

The carotid body is a small chemoreceptor organ located near the bifurcation of the common carotid artery into the internal and external carotid arteries. It plays a crucial role in the regulation of respiration, blood pressure, and pH balance by detecting changes in the chemical composition of the blood, particularly oxygen levels, carbon dioxide levels, and hydrogen ion concentration (pH).

The carotid body contains specialized nerve endings called glomus cells that are sensitive to changes in these chemical parameters. When there is a decrease in oxygen or an increase in carbon dioxide or hydrogen ions, the glomus cells release neurotransmitters such as acetylcholine and dopamine, which activate afferent nerve fibers leading to the brainstem's nucleus tractus solitarius. This information is then integrated with other physiological signals in the brainstem, resulting in appropriate adjustments in breathing rate, depth, and pattern, as well as changes in heart rate and blood vessel diameter to maintain homeostasis.

Dysfunction of the carotid body can lead to various disorders, such as hypertension, sleep apnea, and chronic lung disease. In some cases, overactivity of the carotid body may result in conditions like primary breathing pattern disorders or pseudohypoxia, where the body responds as if it is experiencing hypoxia despite normal oxygen levels.

Respiratory dead space is the portion of each tidal volume (the amount of air that moves in and out of the lungs during normal breathing) that does not participate in gas exchange. It mainly consists of the anatomical dead space, which includes the conducting airways such as the trachea, bronchi, and bronchioles, where no alveoli are present for gas exchange to occur.

Additionally, alveolar dead space can also contribute to respiratory dead space when alveoli are perfused inadequately or not at all due to conditions like pulmonary embolism, lung consolidation, or impaired circulation. In these cases, even though air reaches the alveoli, insufficient blood flow prevents efficient gas exchange from taking place.

The sum of anatomical and alveolar dead space is referred to as physiological dead space. An increased respiratory dead space can lead to ventilation-perfusion mismatch and impaired oxygenation, making it a critical parameter in assessing respiratory function, particularly during mechanical ventilation in critically ill patients.

Halothane is a general anesthetic agent, which is a volatile liquid that evaporates easily and can be inhaled. It is used to produce and maintain general anesthesia (a state of unconsciousness) during surgical procedures. Halothane is known for its rapid onset and offset of action, making it useful for both induction and maintenance of anesthesia.

The medical definition of Halothane is:

Halothane (2-bromo-2-chloro-1,1,1-trifluoroethane) is a volatile liquid general anesthetic agent with a mild, sweet odor. It is primarily used for the induction and maintenance of general anesthesia in surgical procedures due to its rapid onset and offset of action. Halothane is administered via inhalation and acts by depressing the central nervous system, leading to a reversible loss of consciousness and analgesia.

It's important to note that Halothane has been associated with rare cases of severe liver injury (hepatotoxicity) and anaphylaxis (a severe, life-threatening allergic reaction). These risks have led to the development and use of alternative general anesthetic agents with better safety profiles.

Airway resistance is a measure of the opposition to airflow during breathing, which is caused by the friction between the air and the walls of the respiratory tract. It is an important parameter in respiratory physiology because it can affect the work of breathing and gas exchange.

Airway resistance is usually expressed in units of cm H2O/L/s or Pa·s/m, and it can be measured during spontaneous breathing or during forced expiratory maneuvers, such as those used in pulmonary function testing. Increased airway resistance can result from a variety of conditions, including asthma, chronic obstructive pulmonary disease (COPD), bronchitis, and bronchiectasis. Decreased airway resistance can be seen in conditions such as emphysema or after a successful bronchodilator treatment.

Electrolytes are substances that, when dissolved in water, break down into ions that can conduct electricity. In the body, electrolytes are responsible for regulating various important physiological functions, including nerve and muscle function, maintaining proper hydration and acid-base balance, and helping to repair tissue damage.

The major electrolytes found in the human body include sodium, potassium, chloride, bicarbonate, calcium, magnesium, and phosphate. These electrolytes are tightly regulated by various mechanisms, including the kidneys, which help to maintain their proper balance in the body.

When there is an imbalance of electrolytes in the body, it can lead to a range of symptoms and health problems. For example, low levels of sodium (hyponatremia) can cause confusion, seizures, and even coma, while high levels of potassium (hyperkalemia) can lead to heart arrhythmias and muscle weakness.

Electrolytes are also lost through sweat during exercise or illness, so it's important to replace them through a healthy diet or by drinking fluids that contain electrolytes, such as sports drinks or coconut water. In some cases, electrolyte imbalances may require medical treatment, such as intravenous (IV) fluids or medication.

Pia Mater is the inner-most layer of the meninges, which are the protective coverings of the brain and spinal cord. It is a very thin and highly vascularized (rich in blood vessels) membrane that closely adheres to the surface of the brain. The name "Pia Mater" comes from Latin, meaning "tender mother." This layer provides nutrition and protection to the brain, and it also allows for the movement and flexibility of the brain within the skull.

The epidural space is the potential space located outside the dura mater, which is the outermost of the three membranes covering the brain and spinal cord (the meninges). This space runs the entire length of the spinal canal and contains fatty tissue, blood vessels, and nerve roots. It is often used as a route for administering anesthesia during childbirth or surgery, as well as for pain management in certain medical conditions. The injection of medications into this space is called an epidural block.

The Ventilation-Perfusion (V/Q) ratio is a measure used in respiratory physiology to describe the relationship between the amount of air that enters the alveoli (ventilation) and the amount of blood that reaches the alveoli to pick up oxygen (perfusion).

In a healthy lung, these two processes are well-matched, meaning that well-ventilated areas of the lung also have good blood flow. This results in a V/Q ratio close to 1.0.

However, certain lung conditions such as emphysema or pulmonary embolism can cause ventilation and perfusion to become mismatched, leading to a V/Q ratio that is either higher (ventilation exceeds perfusion) or lower (perfusion exceeds ventilation) than normal. This mismatch can result in impaired gas exchange and lead to hypoxemia (low oxygen levels in the blood).

The V/Q ratio is often used in clinical settings to assess lung function and diagnose respiratory disorders.

The brain is the central organ of the nervous system, responsible for receiving and processing sensory information, regulating vital functions, and controlling behavior, movement, and cognition. It is divided into several distinct regions, each with specific functions:

1. Cerebrum: The largest part of the brain, responsible for higher cognitive functions such as thinking, learning, memory, language, and perception. It is divided into two hemispheres, each controlling the opposite side of the body.
2. Cerebellum: Located at the back of the brain, it is responsible for coordinating muscle movements, maintaining balance, and fine-tuning motor skills.
3. Brainstem: Connects the cerebrum and cerebellum to the spinal cord, controlling vital functions such as breathing, heart rate, and blood pressure. It also serves as a relay center for sensory information and motor commands between the brain and the rest of the body.
4. Diencephalon: A region that includes the thalamus (a major sensory relay station) and hypothalamus (regulates hormones, temperature, hunger, thirst, and sleep).
5. Limbic system: A group of structures involved in emotional processing, memory formation, and motivation, including the hippocampus, amygdala, and cingulate gyrus.

The brain is composed of billions of interconnected neurons that communicate through electrical and chemical signals. It is protected by the skull and surrounded by three layers of membranes called meninges, as well as cerebrospinal fluid that provides cushioning and nutrients.

Obstructive Sleep Apnea (OSA) is a sleep-related breathing disorder that occurs when the upper airway becomes partially or completely blocked during sleep, leading to pauses in breathing or shallow breaths. These episodes, known as apneas or hypopneas, can last for 10 seconds or longer and may occur multiple times throughout the night, disrupting normal sleep patterns and causing oxygen levels in the blood to drop.

The obstruction in OSA is typically caused by the relaxation of the muscles in the back of the throat during sleep, which allows the soft tissues to collapse and block the airway. This can result in snoring, choking, gasping for air, or awakening from sleep with a start.

Contributing factors to OSA may include obesity, large neck circumference, enlarged tonsils or adenoids, alcohol consumption, smoking, and use of sedatives or muscle relaxants. Untreated OSA can lead to serious health consequences such as high blood pressure, heart disease, stroke, diabetes, and cognitive impairment. Treatment options for OSA include lifestyle changes, oral appliances, positive airway pressure therapy, and surgery.

Polysomnography (PSG) is a comprehensive sleep study that monitors various body functions during sleep, including brain activity, eye movement, muscle tone, heart rate, respirations, and oxygen levels. It is typically conducted in a sleep laboratory under the supervision of a trained technologist. The data collected during PSG is used to diagnose and manage various sleep disorders such as sleep-related breathing disorders (e.g., sleep apnea), movement disorders (e.g., periodic limb movement disorder), parasomnias, and narcolepsy.

The study usually involves the attachment of electrodes to different parts of the body, such as the scalp, face, chest, and legs, to record electrical signals from the brain, eye movements, muscle activity, and heartbeats. Additionally, sensors may be placed on or near the nose and mouth to measure airflow, and a belt may be worn around the chest and abdomen to monitor breathing efforts. Oxygen levels are also monitored through a sensor attached to the finger or ear.

Polysomnography is often recommended when a sleep disorder is suspected based on symptoms or medical history, and other diagnostic tests have been inconclusive. The results of the study can help guide treatment decisions and improve overall sleep health.

Sleep apnea syndromes refer to a group of disorders characterized by abnormal breathing patterns during sleep. These patterns can result in repeated pauses in breathing (apneas) or shallow breaths (hypopneas), causing interruptions in sleep and decreased oxygen supply to the body. There are three main types of sleep apnea syndromes:

1. Obstructive Sleep Apnea (OSA): This is the most common form, caused by the collapse or obstruction of the upper airway during sleep, often due to relaxation of the muscles in the throat and tongue.

2. Central Sleep Apnea (CSA): This type is less common and results from the brain's failure to send proper signals to the breathing muscles. It can be associated with conditions such as heart failure, stroke, or certain medications.

3. Complex/Mixed Sleep Apnea: In some cases, a person may experience both obstructive and central sleep apnea symptoms, known as complex or mixed sleep apnea.

Symptoms of sleep apnea syndromes can include loud snoring, excessive daytime sleepiness, fatigue, morning headaches, difficulty concentrating, and mood changes. Diagnosis typically involves a sleep study (polysomnography) to monitor breathing patterns, heart rate, brain activity, and other physiological factors during sleep. Treatment options may include lifestyle modifications, oral appliances, positive airway pressure therapy, or even surgery in severe cases.

Sleep is a complex physiological process characterized by altered consciousness, relatively inhibited sensory activity, reduced voluntary muscle activity, and decreased interaction with the environment. It's typically associated with specific stages that can be identified through electroencephalography (EEG) patterns. These stages include rapid eye movement (REM) sleep, associated with dreaming, and non-rapid eye movement (NREM) sleep, which is further divided into three stages.

Sleep serves a variety of functions, including restoration and strengthening of the immune system, support for growth and development in children and adolescents, consolidation of memory, learning, and emotional regulation. The lack of sufficient sleep or poor quality sleep can lead to significant health problems, such as obesity, diabetes, cardiovascular disease, and even cognitive decline.

The American Academy of Sleep Medicine (AASM) defines sleep as "a period of daily recurring natural rest during which consciousness is suspended and metabolic processes are reduced." However, it's important to note that the exact mechanisms and purposes of sleep are still being researched and debated among scientists.

Continuous Positive Airway Pressure (CPAP) is a mode of non-invasive ventilation that delivers pressurized room air or oxygen to maintain airway patency and increase functional residual capacity in patients with respiratory disorders. A CPAP device, which typically includes a flow generator, tubing, and a mask, provides a constant positive pressure throughout the entire respiratory cycle, preventing the collapse of the upper airway during inspiration and expiration.

CPAP is commonly used to treat obstructive sleep apnea (OSA), a condition characterized by repetitive narrowing or closure of the upper airway during sleep, leading to intermittent hypoxia, hypercapnia, and sleep fragmentation. By delivering positive pressure, CPAP helps to stent open the airway, ensuring unobstructed breathing and reducing the frequency and severity of apneic events.

Additionally, CPAP can be used in other clinical scenarios, such as managing acute respiratory distress syndrome (ARDS), chronic obstructive pulmonary disease (COPD) exacerbations, or postoperative respiratory insufficiency, to improve oxygenation and reduce the work of breathing. The specific pressure settings and device configurations are tailored to each patient's needs based on their underlying condition, severity of symptoms, and response to therapy.

Snoring is defined as the vibration of respiratory structures and the resulting sound, due to obstructed air movement during breathing while sleeping. It occurs when the tissues at the back of the throat relax and narrow during sleep, partially blocking the airway. The airflow causes these tissues to vibrate, leading to the snoring sound. Snoring can be a sign of various conditions such as obstructive sleep apnea or other respiratory disorders. It can also be influenced by factors such as alcohol consumption, obesity, and sleeping position.

Sleep disorders are a group of conditions that affect the ability to sleep well on a regular basis. They can include problems with falling asleep, staying asleep, or waking up too early in the morning. These disorders can be caused by various factors such as stress, anxiety, depression, medical conditions, or substance abuse.

The American Academy of Sleep Medicine (AASM) recognizes over 80 distinct sleep disorders, which are categorized into the following major groups:

1. Insomnia - difficulty falling asleep or staying asleep.
2. Sleep-related breathing disorders - abnormal breathing during sleep such as obstructive sleep apnea.
3. Central disorders of hypersomnolence - excessive daytime sleepiness, including narcolepsy.
4. Circadian rhythm sleep-wake disorders - disruption of the internal body clock that regulates the sleep-wake cycle.
5. Parasomnias - abnormal behaviors during sleep such as sleepwalking or night terrors.
6. Sleep-related movement disorders - repetitive movements during sleep such as restless legs syndrome.
7. Isolated symptoms and normal variants - brief and occasional symptoms that do not warrant a specific diagnosis.

Sleep disorders can have significant impacts on an individual's quality of life, productivity, and overall health. If you suspect that you may have a sleep disorder, it is recommended to consult with a healthcare professional or a sleep specialist for proper evaluation and treatment.

... usually results from deep or rapid breathing, known as hyperventilation. Hypocapnia is the opposite of hypercapnia. ... which is often associated with hypocapnia Laffey JG, Kavanagh BP (2002). "Hypocapnia". N. Engl. J. Med. 347 (1): 43-53. doi: ... The main physiologic causes of hypocapnia are related to hyperventilation. Hypocapnia is sometimes induced in the treatment of ... In fact hypocapnia reduces the oxygen levels available to the brain due to the elevated affinity of oxygen to hemoglobin (Bohr ...
Self-induced hypocapnia. Hyperventilation leading to hypocapnia and subsequent loss of an appropriate urge to breathe is the ... Hypocapnia reduces the reflexive respiratory drive, allowing the delay of breathing and leaving the diver susceptible to loss ... The absence of any symptoms of hypocapnia is not an indication that the diver's carbon dioxide level is within safe limits and ... The absence of any symptoms of hypocapnia is not an indication that the diver's carbon dioxide is within safe limits and cannot ...
Hypocapnia, which stimulates hypoventilation Obesity; see Obesity hypoventilation syndrome Chronic mountain sickness, a ... hypocapnia), rather than hypercapnia. Bradypnea Dyspnea Hyperventilation Hypopnea List of terms of lung size and activity " ...
Bruton A, Holgate ST (May 2005). "Hypocapnia and asthma: a mechanism for breathing retraining?". Chest. 127 (5): 1808-11. doi: ... in part due to the lack of research supporting the theory that hyperventilation and hypocapnia causes disease, with one review ... method purports to retrain the body's breathing pattern to correct for the presumed chronic hyperventilation and hypocapnia, ...
Moreover, this hypocapnia and release of adrenaline during a panic attack cause vasoconstriction resulting in slightly less ... This leads to shifts in blood pH (respiratory alkalosis or hypocapnia), causing compensatory metabolic acidosis activating ... Hyperventilation syndrome can cause respiratory alkalosis and hypocapnia. This syndrome often involves prominent mouth ...
Due to ventilatory responses, this process leads to secondary hypocapnia. Because birds are exposed to a wide variety of toxic ...
This contingency in the environment causes hypocapnia which decreases ventilation. Chronic hypoxia results in further ...
"Cerebrovascular responses to hypoxia and hypocapnia in Ethiopian high altitude dwellers". Stroke. 39 (2): 336-342. doi:10.1161/ ...
This condition is thought to result from severe hypocapnia that induces blood vessels in the brain to constrict, leading to ... Chang, Chia-Hsuin; Kuo, PH; Hsu, CH; Yang, PC (2000). "Persistent Severe Hypocapnia and Alkalemia in a 40-Year-Old Woman". ...
"Independent cerebral vasoconstrictive effects of hyperoxia and accompanying arterial hypocapnia at 1 ATA". J. Appl. Physiol. 95 ...
Michenfelder JD, Milde JH (1977). "Failure of prolonged hypocapnia, hypothermia, or hypertension to favorably alter acute ...
The effects of space exposure can result in ebullism, hypoxia, hypocapnia, and decompression sickness. In addition to these, ...
This leads to hypocapnia, a reduced concentration of carbon dioxide dissolved in the blood. The body normally attempts to ...
Above 5,500 metres (18,000 ft), marked hypoxemia, hypocapnia, and alkalosis are characteristic of extreme altitudes. ...
hyperventilation-induced blackout See: underwater blackout syndrome hypocapnia Abnormally low tissue and blood carbon dioxide ...
Snorkelers who hyperventilate to extend sub-surface time can experience hypocapnia if they hyperventilate prior to submerging. ...
Fatigue Hyperventilation, paradoxically: self-induced hypocapnia, such as in the fainting game or in shallow water blackout. ...
The mechanism for blackout on ascent differs from hyperventilation induced hypocapnia expedited blackouts and does not ... Hyperventilation depletes the blood of carbon dioxide (hypocapnia), which causes respiratory alkalosis (increased pH), and ... Abnormally high tissue carbon dioxide levels Hypocapnia - State of reduced carbon dioxide in the blood Hypoxia - Medical ... blackout is precipitated by depressurisation on ascent from depth while shallow water blackout is a consequence of hypocapnia ...
Hypocapnia - State of reduced carbon dioxide in the blood, decreased level of carbon dioxide Inert gas asphyxiation - ... Hypercapnia is the opposite of hypocapnia, the state of having abnormally reduced levels of carbon dioxide in the blood. ...
"Changes in Human Cerebral Blood Flow and Cerebral Blood Volume during Hypercapnia and Hypocapnia Measured by Positron Emission ...
Prolonged exertion in low oxygen also causes serious hypocapnia, lower carbon dioxide in the bloodstream, which may play a role ...
The two mechanisms are strangulation and self-induced hypocapnia and work as follows: A ligature such as a belt or rope around ... The second mechanism requires hyperventilation (forced overbreathing) until symptoms of hypocapnia such as tingling, light- ... In both strangulation and self-induced hypocapnia blackouts the victim may experience dreaming or hallucinations, though ... bear-hug is replaced by pressure on the neck in which case blackout is a hybrid of strangulation and self-induced hypocapnia. ...
At extreme altitude, above 5,500 metres (18,000 ft), one can expect significant hypoxemia, hypocapnia and alkalosis, with ...
At extreme altitude, above 5,500 metres (18,000 ft), one can expect significant hypoxemia, hypocapnia and alkalosis, with ...
... in alveolar gas exchange usually do not cause hypoventilation but tend to cause stimulation of ventilation and hypocapnia ...
It is one cause of hyperventilation with others including infection, blood loss, heart attack, hypocapnia or alkalosis due to ... hypocapnia) in their blood and other tissues. While oxygen is abundant in the bloodstream, HVS reduces effective delivery of ...
... the breathing disorder Hypocapnia, a physiological result of hyperventilating "Hyperventilating" (song), a 2006 song by Tami ...
... hypocapnia MeSH C23.888.852.638 - hypoventilation MeSH C23.888.852.761 - mouth breathing MeSH C23.888.852.779 - respiratory ...
... whether suspension or short drop hanging Self-induced hypocapnia by hyperventilation, as in shallow water or deep water ...
Abnormally high tissue carbon dioxide levels Hypocapnia - State of reduced carbon dioxide in the blood Hypothermia - Human body ...
Hypocapnia usually results from deep or rapid breathing, known as hyperventilation. Hypocapnia is the opposite of hypercapnia. ... which is often associated with hypocapnia Laffey JG, Kavanagh BP (2002). "Hypocapnia". N. Engl. J. Med. 347 (1): 43-53. doi: ... The main physiologic causes of hypocapnia are related to hyperventilation. Hypocapnia is sometimes induced in the treatment of ... In fact hypocapnia reduces the oxygen levels available to the brain due to the elevated affinity of oxygen to hemoglobin (Bohr ...
Hypocapnia has long been known to cause coronary artery vasoconstriction. Some new cardiology tests are accompanied by the ... Methods: Severe hypocapnia (a PetCO2 level of 20 mmHg) lasting ,15 min was mechanically induced by facemask, while conscious ... Hypocapnia produced no other significant effects (p , 0.05) on their electro- or echocardiogram. All 10 angina patients ... Hypocapnia alone fails to provoke important electrocardiogram changes in coronary artery diseased patients ...
Hypoxia, hypocapnia and spirometry at altitude (vol 92, pg 593, 1997) Pollard AJ., Barry PW., Mason NP., Collier DJ., Pollard ...
Hypoxia, hypocapnia and spirometry at altitude (vol 92, pg 593, 1997) Pollard AJ., Barry PW., Mason NP., Collier DJ., Pollard ...
Hypocapnia. N Engl J Med. 2002;347:43-53.. 6. Collins C. Yoga: Intuition, preventive medicine and treatment. J Obstet ...
T1 - Hypocapnia and hypercapnia are predictors for ICU admission and mortality in hospitalized patients with community-acquired ... Hypocapnia and hypercapnia are predictors for ICU admission and mortality in hospitalized patients with community-acquired ... Hypocapnia and hypercapnia are predictors for ICU admission and mortality in hospitalized patients with community-acquired ... Hypocapnia and hypercapnia are predictors for ICU admission and mortality in hospitalized patients with community-acquired ...
Permissive hypercapnia may also protect against hypocapnia-induced brain hypoperfusion and subsequent periventricular ...
Hyperpnea and hypocapnia occurs at this stage in most patients. [6] In some patients Stage 2 is abbreviated. This is especially ... 24] Central hypovolemia can also result in hyperpnea and hypocapnia in nearly 50% of patients [7] through a baroreflex mediated ... Hypocapnia and cerebral hypoperfusion in orthostatic intolerance. Stroke. 1998. 29:1876-1881. [QxMD MEDLINE Link]. ... 6, 70, 7] Hyperpnea and resultant hypocapnia precede unconsciousness in virtually every vasovagal syncope patient. [6] ...
The chronic hypoxia and hypocapnia that is an inescapable consequence of high altitude living has profound effects upon the ... chronic hypoxia and hypocapnia due to permanent residence at high altitude; and orthostatic stress. ... Cerebrovascular responses to hypoxia and hypocapnia in Ethiopian high altitude dwellers. Stroke, 39: 336-342. ...
Acute respiratory failure-hypoxic, hypocapnia, or both. *AKI. *Respiratory distress syndrome, Type 1 ...
or hypocapnia). This results in decreased pH.. Respiratory acidosis. This process is characterized by alveolar hypoventilation ... It is characterized by alveolar hyperventilation that results in decreased PCO2 levels (hypocapnia) caused by hypoxemia, direct ...
Hypocapnia and increased ventilatory responsiveness in patients with idiopathic central sleep apnea. Am J Respir Crit Care Med ...
Prevent Hypoxia and hypocapnia, Hyperglycemia and Electrolyte disturbances. *Temperature targeted management of 36 C may offer ...
Signs and Symptoms of Hypocapnia. The objective signs of hypocapnia most often observed in a freediver are:. (a)Muscle ... The effect of hypocapnia on the respiratory system is primarily on the blood buffer system. Seventy percent of the carbon ... In more severe hypocapnia, the whole body becomes stiff (a condition referred to as tetany) due to contraction of skeletal ... Two primary effects experienced by an ascending freediver are hypocapnia and alkalosis, both of which have an effect on the ...
Impact of hypocapnia and cerebral perfusion on orthostatic tolerance. J Physiol. 2014;592:5203-19 ...
Chen, J. J., and Pike, G. B. (2010a). Global cerebral oxidative metabolism during hypercapnia and hypocapnia in humans: ... MRI measurement of the BOLD-specific flow-volume relationship during hypercapnia and hypocapnia in humans. Neuroimage 53, 383- ... Changes in human cerebral blood flow and cerebral blood volume during hypercapnia and hypocapnia measured by positron emission ...
Arterial blood gas measurement can provide information about altered pH, hypercapnia, hypocapnia or hypoxemia. This measurement ...
Serial monitoring of CO2 reactivity following sport concussion using hypocapnia and hypercapnia. Brain Inj 2013;27:346-53.doi: ...
... perspective focused on specific changes in cerebral vasoconstriction associated with hyperventilation-induced hypocapnia. The ... perspective focused on specific changes in cerebral vasoconstriction associated with hyperventilation-induced hypocapnia. The ...
In these patients, hypercapnia, hypocapnia, and hypoxemia are avoided. Generally, iatrogenic hyperventilation is discouraged. ...
In contrast to enflurane, attempts to elicit seizure-like EEG activity during hypocapnia with rhythmic auditory stimuli have ... There is no evidence that sevoflurane is associated with epileptiform activity during normocapnia or hypocapnia. ...
... or hypocapnia and hypercapnia, which is when carbon dioxide levels in the blood reach abnormally low and high levels, ...
In the OR, hypocapnia can result from a reduction in the total systemic carbon dioxide delivered to the lungs. This reduction ... Mechanisms of hypoxemia and hypocapnia in pulmonary embolism. Am J Respir Crit Care Med. 1995 Jul. 152 (1):336-47. [QxMD ... Waveform capnography will show a gradual decrease in end-tidal carbon dioxide secondary to this hypocapnia. [13] ...
... some symptoms associated with the syndrome have been shown to be unrelated to hypocapnia and may be mediated by other ... isocapnic hyperventilation studies showed that many of the symptoms produced by overbreathing are independent of hypocapnia.9 ...
Snorkelers who hyperventilate to extend sub-surface time can experience hypocapnia if they hyperventilate prior to submerging. ...
Hypocapnia. Bronchoconstriction. Bronchospasm. Dyspnea. Shortness of breath anxiety. Shortness of breath causes. Difficulty ... Hence, hypocapnia (reduced CO2 in the alveoli of the lungs) can cause cellular lung damage due to biochemical reasons ... As we discussed before, alveolar hypocapnia leads to systemic cell hypoxia, generation of free radicals, and immune system ... American doctors from the University of Washington Medical School in Seattle found that "Hypocapnia worsens arterial blood ...
... performance alterations due to hypoxia or hypocapnia, and hypobaric and hyberbaric operations. ...
  • Hypocapnia usually results from deep or rapid breathing, known as hyperventilation. (wikipedia.org)
  • citation needed] The main physiologic causes of hypocapnia are related to hyperventilation. (wikipedia.org)
  • Self-induced hypocapnia through hyperventilation is the basis for the dangerous schoolyard fainting game. (wikipedia.org)
  • Freediving blackout - Loss of consciousness caused by cerebral hypoxia towards the end of a breath-hold dive, where hyperventilation and the subsequent hypocapnia is a cause Hypercapnia - Abnormally high tissue carbon dioxide levels, increased level of carbon dioxide Hyperventilation syndrome - Medical condition involving hyperventilating, which is often associated with hypocapnia Laffey JG, Kavanagh BP (2002). (wikipedia.org)
  • Hypotension (target mean arterial blood pressure: 35 to 38 or 27 to 30 mm Hg) was induced by blood withdrawal and nitroprusside infusion, and hypocapnia by hyperventilation (target PaCO2: 28 to 30 and 23 to 25 mm Hg). (nih.gov)
  • Key words: Lungs, hyperventilation: hypocapnia. (silverchair.com)
  • MCAVm responses to hypocapnia were studied by voluntary hyperventilation with PET,O2 clamped at 100 and 50 mmHg. (hud.ac.uk)
  • Hypocapnia apnea was produced by hyperventilation. (ntnu.edu.tw)
  • Hyperventilation causes acute hypocapnia resulting in cerebral vasoconstriction, hypocalcemia, a shift in the oxygen-hemoglobin dissociation curve, and reduced oxygen delivery. (cannabis.net)
  • We therefore hypothesized that hyperventilation and arousals from sleep interact to cause hypocapnia and subsequent central apneas in patients with idiopathic central sleep apnea (ICSA). (elsevierpure.com)
  • We conclude that arousals and hyperventilation interact to trigger hypocapnia and central apneas in ICSA. (elsevierpure.com)
  • A lower rate of hyperventilation/hypocapnia in intubated patients. (simmt.org)
  • Hyperventilation is the state of rapid breathing which results in the reduction in carbon dioxide levels (below normal) thereby leading to hypocapnia . (wikidoc.org)
  • Here we examined cerebral blood flow responses to hypoxia and hypocapnia, separately and together, in Andean high-altitude dwellers, including some with chronic mountain sickness (CMS), which is characterized by excessive polycythaemia. (hud.ac.uk)
  • The similarity of the results from the two groups of altitude dwellers suggests that haematocrit is unlikely to greatly affect cerebrovascular reactivity to hypoxia and hypocapnia. (hud.ac.uk)
  • Death takes place through hypoxia and hypocapnia, oxygen and carbon dioxide deprivation, respectively. (exitinternational.net)
  • Fifty-seven sevoflurane-midazolam anesthetized piglets aged 4 to 6 weeks were randomly allocated to control (n=9), hypotension (n=18), hypocapnia (n=20), or combined hypotension and hypocapnia (n=10). (nih.gov)
  • There is also increasing concern about the potential adverse effects of perioperative hypotension and hypocapnia on neurocognitive development in infants. (bmj.com)
  • Acute hypocapnia causes hypocapnic alkalosis, which causes cerebral vasoconstriction leading to cerebral hypoxia, and this can cause transient dizziness, fainting, and anxiety. (wikipedia.org)
  • The smaller vasodilatation to hypoxia and larger vasoconstriction to hypoxic hypocapnia at high altitude suggest that cerebrovascular responsesmay be impaired at the high altitude, i.e. a maladaptation. (hud.ac.uk)
  • It is conceivable that the presence of HFrEF would further deteriorate this scenario by adding components of dysfunctional cerebral autoregulation, lower cardiac output and hypocapnia-induced vasoconstriction [ 4 ]. (ersjournals.com)
  • Hypocapnia is the opposite of hypercapnia. (wikipedia.org)
  • Our results show that contractility was reduced with hypercapnia (when end-tidal carbon dioxide was 7.5 per cent or higher), although hypocapnia (end-tidal carbon dioxide, 3 per cent) had no effect on diaphragmatic contractility. (nih.gov)
  • The effects of hypercapnia and hypocapnia on the activities of the cardiac and pulmonary vagal single fibers were examined in the decerebrated, unanesthetized, paralyzed, and vagotomized cats. (ntnu.edu.tw)
  • The PCO2 in the solution was 36 +/- 3 mmHg (normocapnia), 19 +/- 2 mmHg (moderate hypocapnia), or 5 +/- 2 mmHg (severe hypocapnia), respectively. (silverchair.com)
  • Hypocapnia was eTCO(2) ≤ 32 mmHg. (cdc.gov)
  • healthy volunteers ( = 32, 18 ± 3 yr) were compared with POTS, grouped by presence [POTS-low end-tidal CO (↓ETCO), = 26, 19 ± 2 yr] or absence [POTS-normal upright end-tidal carbon dioxide (nlCO), = 28, 19 ± 3 yr] of standing hypocapnia defined by end-tidal CO (ETCO) ≤ 30 mmHg at steady-state, measuring middle cerebral artery CBv, heart rate (HR), and beat-to-beat blood pressure (BP). (touro.edu)
  • Arterial blood gas analysis showed mild hypoxemia and hypocapnia (PaO 2 73 mm Hg and PaCO 2 34 mm Hg on room air). (cdc.gov)
  • Arterial hypocapnia (CO2 deficiency) causes tissue hypoxia that triggers numerous pathological effects (see links with medical studies below). (normalbreathing.com)
  • Manifestación clínica producida por un déficit de dióxido de carbono en la sangre arterial. (bvsalud.org)
  • 9. Hypocapnia induces caspase-3 activation and increases Abeta production. (nih.gov)
  • What this did was quickly expel all of the CO2 from his blood that induces hypocapnia, which in turn can begin to produce symptoms that exacerbate the narrative in your head. (cannabis.net)
  • Hypocapnia, either resting or induced by OC, was the most frequent abnormality, followed by postural orthostatic tachycardia. (cdc.gov)
  • orthostatic tachycardia, hypocapnia or hypotension. (cdc.gov)
  • Hypocapnia at rest or induced by OC was more common and more likely to persist than postural orthostatic tachycardia. (cdc.gov)
  • Hypocapnia also results in bronchoconstriction in order to decrease ventilation. (wikipedia.org)
  • These results indicate that CCh, NE, and hypocapnia stimulate PI turnover in the airway smooth muscle, which would cause bronchoconstriction, and hypocapnia also augments NE- and CCh-induced PI turnover, which could cause worsening of exercise-induced asthma and vagotonic asthma, respectively. (silverchair.com)
  • Using an animal model, we investigated serum S100b as an acute biomarker of cerebral hypoperfusion and cerebral cell dysfunction during hypotension, hypocapnia, or combined hypotension/hypocapnia during GA. (nih.gov)
  • Hypoxia, hypotension and inadvertent hypocapnia are the most frequent causes of jugular desaturations, and periods of low brain tissue oxygen tension. (nih.gov)
  • The most frequent abnormality, hypocapnia, would be missed without capnography. (cdc.gov)
  • Dyspnea is frequent in postural tachycardia syndrome (POTS) and is associated with upright hyperpnea and hypocapnia that drives sinus tachycardia. (touro.edu)
  • In fact hypocapnia reduces the oxygen levels available to the brain due to the elevated affinity of oxygen to hemoglobin (Bohr effect) hence highly increasing the chances of blackout. (wikipedia.org)
  • This is sensible since hypocapnia or over breathing reduces oxygen levels in body cells (see the image of the brain). (normalbreathing.com)
  • The activities of the 3 pulmonary vagal units tested with hypocapnia decreased significantly. (ntnu.edu.tw)
  • Hypotension and/or hypocapnia might increase general anesthesia (GA)-related neuromorbidity in infants, but safe levels of perioperative blood pressure are poorly defined. (nih.gov)
  • Because there is a direct relationship between phosphatidylinositol (PI) metabolism and airway smooth muscle contraction induced by muscarinic agonists, the authors examined the effects of carbachol (CCh), norepinephrine (NE), and hypocapnia on PI turnover in the airway smooth muscle. (silverchair.com)
  • Hypocapnia (from the Greek words υπό meaning below normal and καπνός kapnós meaning smoke), also known as hypocarbia, sometimes incorrectly called acapnia, is a state of reduced carbon dioxide in the blood. (wikipedia.org)
  • citation needed] Because the brain stem regulates breathing by monitoring the level of blood CO2 instead of O2, hypocapnia can suppress breathing to the point of blackout from cerebral hypoxia, as exhibited in shallow water blackout. (wikipedia.org)
  • Blood gas analyses showed slight hypocapnia and significant carboxyhemoglobinemia and methemoglobinemia. (cdc.gov)
  • Cerebral blood flow is known to increase in response to hypoxia and to decrease with hypocapnia. (hud.ac.uk)
  • We determined whether iOH drives hypocapnia in POTS by low BP or decreased cerebral blood velocity (CBv). (touro.edu)
  • Alternatively, hypocapnia results in constriction of brain's blood vessels causing diminished blood flow leading to lightheadedness . (wikidoc.org)
  • The purpose of this study is to evaluate the effects of hypocapnia on postural standing balance using the sharpened Romberg test (SRT). (mayo.edu)
  • This results in low CO 2 content ( hypocapnia ) with each rapid and deep breath. (wikidoc.org)
  • en.wikipedia.org/wiki/Altitude_sickness Two really bas ones are high-altitude pulmonary edema (HAPE) and high-altitude cerebral edema (HACE). (stackexchange.com)
  • S100b did not increase following 60 minutes of systemic hypotension and/or hypocapnia during GA in piglets. (nih.gov)
  • Hypocapnia is maintained during the standing response and might account for persistent postural tachycardia. (touro.edu)

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