AutoregulationVascular reactivityStenosisVelocitySystemicHypercapniaInhalationMiddle CerebrCardiac OutputIndicesMmHgVenousHumansTranscranialEndothelialSpontaneousCerebral circulationStrokePatientsIndexTestNormalCerebralAutoregulationSystolicHomeostasisPeripheralPartialCardiovascularBlood pressureTime
Autoregulation11
- Cerebral autoregulation maintains constant blood flow (CBF) through the brain in spite of changing mean arterial pressure [ 8 ]. (hindawi.com)
- Pressure-autoregulation, CO2 reactivity and asymmetry of haemodynamic parameters in patients with carotid artery stenotic disease. (ox.ac.uk)
- Haemodynamic reserve can be estimated by measuring cerebrovascular reactivity induced by breathing CO2 and pressure-autoregulation by analyzing spontaneous slow fluctuation in arterial pressure and MCA blood flow velocity. (ox.ac.uk)
- We evaluated the relationship between clinical status, CO2 reactivity, pressure-autoregulation and other haemodynamic variables derived from Transcranial Doppler ultrasonography in patients with carotid artery disease. (ox.ac.uk)
- The pressure-autoregulation index was calculated as correlation coefficient between slow waves in blood flow velocity and arterial pressure. (ox.ac.uk)
- RESULTS: The increase in CO2 produced a consistent rise in arterial pressure and blood flow velocity and weakened the pressure autoregulation. (ox.ac.uk)
- Both CO2 reactivity and pressure-autoregulation index correlated with a degree of carotid artery stenosis. (ox.ac.uk)
- Both CO2 reactivity and pressure-autoregulation describe the magnitude of haemodynamic deficit caused by stenosis, pulsatility index expresses the asymmetry of stenosis. (ox.ac.uk)
- Cerebral pressure reactivity is a fundamental component of cerebral autoregulation, whereby cerebrovascular resistance is altered in response to changes in cerebral perfusion pressure (CPP) ( 8 ). (frontiersin.org)
- Thus, one can estimate that if one's cerebrovascular autoregulation is regionally impaired, with a CPP around 60mmHg one should have optimal blood flow both to the regions with impaired autoregulation and to the regions where it is preserved. (derangedphysiology.com)
- Illustration of the traditionally viewed concept of cerebral autoregulation (black line) compared to the pressure‐dependent relationship of cerebrovascular control (red line). (comprehensivephysiology.com)
Vascular reactivity2
- 12 The relatively small number of studies to have assessed vascular reactivity and blood flow in the systemic circulation of these patients, however, prevents identification of the mechanisms underlying these abnormalities. (bmj.com)
- Modelling vascular reactivity to investigate the basis of the relationship between cerebral blood volume and flow under CO2 manipulation. (ox.ac.uk)
Stenosis1
- Noninvasive imaging of asymptomatic brain aneurysms, arteriovenous malformations, and intracranial arterial stenosis became available. (hindawi.com)
Velocity4
- Functional abnormalities, including reduced blood flow velocity and increased resistance in a number of ocular arteries, have been demonstrated within the ophthalmic circulation of patients with NPG. (bmj.com)
- Arterial pressure and blood flow velocity were monitored during CO2 reactivity tests. (ox.ac.uk)
- Middle cerebral artery blood velocity (MCAv, transcranial Doppler ultrasound), mean arterial pressure (MAP, finger photoplethysmography), and end-tidal partial pressure of carbon dioxide (PETCO2, capnography) were recorded during normocapnia and 3 mins of iso-oxic hypercapnea (5% CO2).Cerebrovascular resistance/conductance indices (CVRi/CVCi) were calculated asMAP/MCAv and MCAv/MAP, respectively, and CVRCO2 as the percentage increase inMCAv from baseline per millimeter of mercury (mm Hg) increase in PETCO2. (southwales.ac.uk)
- Increased flow velocity may be associated with a younger age, anemia, severely increased blood pressure, hypermetabolic states such as hyperthyroidism and anemia, increased carbon dioxide tension or some drugs such as an acetazolamid and mannitol. (biomedcentral.com)
Systemic5
- It has been proposed that vascular dysfunction contributes to the pathogenesis of glaucoma and, in particular, NPG as this condition is associated with the presence of widespread cerebrovascular and systemic cardiovascular disease. (bmj.com)
- It is conceivable that NPG is associated with a generalised vascular defect which produces alterations in both the ocular and systemic circulations. (bmj.com)
- 7, 8 Functional abnormalities in the systemic circulation of patients with NPG are indicated by the high prevalence of migraine and Raynaud's disease, which are indicative of increased vasospasm in these individuals. (bmj.com)
- Because we can hardly measure the latter and we only guess at the former, a useful approximation is to subtract intracranial pressure (ICP) from the mean systemic arterial pressure (MAP). (derangedphysiology.com)
- Whether alterations of systemic or cerebral circulation might play a role in sepsis-induced encephalopathy, however, has not yet been determined. (biomedcentral.com)
Hypercapnia1
- Hence, hypercapnia represents a robust model to test whether flavanol-mediated increases in endothelial function (as assessed by gold-standard FMD) mediate benefits in cerebrovascular and cognitive function. (nature.com)
Inhalation1
- Can Alterations in Cerebrovascular CO 2 Reactivity Be Identified Using Transfer Function Analysis without the Requirement for Carbon Dioxide Inhalation? (elsevierpure.com)
Middle Cerebr1
- The cerebral capillary closing pressure was determined from transcranial Doppler measurements of the arterial blood flow of the middle cerebral artery and the arterial pressure curve. (biomedcentral.com)
Cardiac Output1
- If spontaneous ventilation is maintained, the major cardiovascular effect is arterial hypotension (sometimes greater than a 30% decrease) with little or no change in heart rate and no appreciable decrease in cardiac output. (guidelinecentral.com)
Indices1
- Arterial pressure-corrected and non-corrected indices of CO2 reactivity were calculated to compare an influence of rise in arterial pressure during the test. (ox.ac.uk)
MmHg3
- 9 mmHg)‐induced cerebrovascular flow‐mediated dilatation (cFMD) was induced, calculated as relative peak dilatation from baseline diameter. (waseda.jp)
- The mean (SD) intracranial pressure (ICP) was 17.6 + 9.0 mmHg, MAP was 89.7 + 9.0 mmHg, and pressure-reactivity index (PRx) was −0.01 + 0.23 a.u. (frontiersin.org)
- Recording of the temporal relationship of repeating oscillatory pattern between arterial blood pressure (BP) and muscle sympathetic nerve activity (MSNA) obtained from a healthy human during simulated hemorrhage of an estimated 25% blood loss induced by 70 mmHg LBNP. (comprehensivephysiology.com)
Venous2
- Thus, it is the difference in mean cereberal arterial pressure and the mean cereral venous pressure. (derangedphysiology.com)
- After approval of the institutional ethics committee, 10 mechanically ventilated patients with sepsis syndrome and pathological electroencephalogram patterns underwent measurements of cerebral blood flow and jugular venous oxygen saturation before and after reduction of the arterial carbon dioxide partial pressure by 0.93 ± 0.7 kPa iu by ypervent ilation. (biomedcentral.com)
Humans1
- Comparisons of mean arterial blood pressures in rats (closed circles, solid lines) and humans (open circles, broken lines) during progressive lower body negative pressure (A) and controlled hemorrhage (B). (comprehensivephysiology.com)
Transcranial1
- Transcranial Doppler (TCD) is a noninvasive, less expensive, safe, and harmless technique being commonly used studying main intracranial arteries especially in cerebrovascular occlusive disease. (biomedcentral.com)
Endothelial4
- In this review, the role of cerebrovascular reactivity to L-arginine (CVR-L-Arg) for assessment of cerebral endothelial function is discussed. (hindawi.com)
- Endothelial function is not uniform throughout the arterial system. (hindawi.com)
- In the past few years cerebrovascular reactivity to L-arginine by means of TCD has emerged as a parameter for evaluation of cerebral endothelial function [ 3 - 7 ]. (hindawi.com)
- Since the cerebrovascular shear rate did not change during exercise, it is possible that acute handgrip exercise is not sufficient stimulation to improve cerebral endothelial function. (waseda.jp)
Spontaneous1
- During maintenance of general anesthesia, propofol injectable emulsion causes a decrease in spontaneous minute ventilation usually associated with an increase in carbon dioxide tension which may be marked depending upon the rate of administration and concurrent use of other medications (e.g., opioids, sedatives, etc. (pfizermedicalinformation.com)
Cerebral circulation2
- Cerebral perfusion pressure is the driving pressure gradient which produces flow in the cerebral circulation against the resistance of cerebral vessels. (derangedphysiology.com)
- In most of the former studies concerning cerebral haemodynamics during sepsis syndrome, only a few aspects of cerebral circulation had been investigated. (biomedcentral.com)
Stroke1
- Age-related impairments in cerebral blood flow and cerebrovascular reactivity to carbon dioxide (CVRCO2) are established risk factors for stroke that respond favorably to aerobic training. (southwales.ac.uk)
Patients1
- We hypothesized that cerebral haemodynamics and carbon dioxide reactivity would be impaired in patients with sepsis syndrome and pathological electroencephalogram patterns. (biomedcentral.com)
Index1
- In a retrospective observational study of adult TBI our group has recently demonstrated an association between elevated blood glucose and impaired cerebral pressure-reactivity index (PRx) ( 7 ). (frontiersin.org)
Test1
- 0.0001) than the non-corrected one, indicating that the rise in arterial pressure during the test tends to over-estimate CO2 reactivity. (ox.ac.uk)
Normal2
- If anesthesia is continued by infusion of DIPRIVAN, the stimulation of endotracheal intubation and surgery may return arterial pressure towards normal. (guidelinecentral.com)
- If anesthesia is continued by infusion of propofol injectable emulsion, the stimulation of endotracheal intubation and surgery may return arterial pressure towards normal. (pfizermedicalinformation.com)
Cerebral3
- [ 1 , 2 ] The cerebro-protective mechanisms of mild hypothermia include a reduction in cerebral blood flow and arterial ammonia concentrations, which together result in reduced delivery of ammonia to the brain. (medscape.com)
- Moreover, if a significant carotid stenosis or occlusion is considered as one of the most important factors affecting cerebral vasomotor reactivity, very recently an association between altered reactivity and CAD has been established, even in the absence of significant carotid stenosis [ 14 ]. (biomedcentral.com)
- 3 Direct cerebrovascular compression caused by brain tissue shifting can lead to secondary infarction, especially in the territories of the anterior and posterior cerebral artery. (j-stroke.org)
Autoregulation1
- Mild hypothermia facilitates the hemodynamic management of patients with ALF by counteracting the hyperdynamic circulation of these patients, reducing vasopressor requirements, and restoring cerebrovascular autoregulation. (medscape.com)
Systolic3
- Randall and Rohse (181) and Cotton (42) also have shown that stimulation of the left stellate ganglion increases markedly the 'force' of myocardial contrac- tion, producing striking increases in arterial systolic, pulse and diastolic pressures. (nih.gov)
- We applied linear mixed models with random participant intercepts to investigate the association of fine particles, ozone, and ambient temperature with systolic, diastolic, and mean arterial BP in a multipollutant model, controlling for season, meteorological variables, and subject characteristics. (nih.gov)
- Results: An interquartile increase in ambient fine particle mass [particulate matter (PM) with an aerodynamic diameter of ≤ 2.5 μm (PM 2.5 )] and in the traffic component black carbon in the previous 5 days (3.54 and 0.25 μg/m 3 , respectively) predicted increases of 1.4 mmHg [95% confidence interval (CI): 0.0, 2.9 mmHg] and 2.2 mmHg (95% CI: 0.4, 4.0 mmHg) in systolic BP (SBP) at the population geometric mean, respectively. (nih.gov)
Homeostasis1
- Permanent residence at high-altitude and chronic mountain sickness (CMS) may alter the cerebrovascular homeostasis and orthostatic responses. (researchgate.net)
Peripheral2
- The magnitude of the relative changes in stroke work and peripheral resistance suggests that the cardiac responses to baroreceptor stimula- tion play an important role in the reflex regulation of arterial pressure. (nih.gov)
- The aim of this study is the creation of a four-step ultrasound examination to evaluate and monitor the peripheral, the extra and the intra-cranial assessment of the arterial early damage in smokers. (biomedcentral.com)
Partial2
- The aim of this study is to determine whether hypocapnia [defined as the partial pressure of arterial carbon dioxide (PaCO2 ) below 35 mmHg] on admission could be associated with in-hospital all-cause mortality in AHF. (bvsalud.org)
- As time passes following arterial occlusion or partial occlusion, the basic idea is that for a period of time collateral circulation will sustain normal neurological function, which is dependent on the individual and their risk factors. (medscape.com)
Cardiovascular1
- If spontaneous ventilation is maintained, the major cardiovascular effect is arterial hypotension (sometimes greater than a 30% decrease) with little or no change in heart rate and no appreciable decrease in cardiac output. (nih.gov)
Blood pressure1
- Objective: We examined whether short-term exposures to air pollution (fine particles, ozone) and heat resulted in perturbation of arterial blood pressure (BP) in persons with type 2 diabetes mellitus (T2DM). (nih.gov)
Time1
- Intravenous injection of a therapeutic dose of propofol induces, with minimal excitation, usually within 40 seconds from the start of injection (the time for one arm-brain circulation). (nih.gov)