scholarly journals Comparison of Cerebral Vascular Reactivity Measures Obtained Using Breath-Holding and CO2 Inhalation

2013 ◽  
Vol 33 (7) ◽  
pp. 1066-1074 ◽  
Author(s):  
Felipe B Tancredi ◽  
Richard D Hoge
Keyword(s):  
Arterial Spin Labeling ◽  
Vascular Reactivity ◽  
Automated System ◽  
Breath Holding ◽  
Breath Hold ◽  
Cerebral Vasculature ◽  
Fixed Concentration ◽  
Physiologic Modeling ◽  
End Tidal ◽  
Cerebral Vascular

Stimulation of cerebral vasculature using hypercapnia has been widely used to study cerebral vascular reactivity (CVR), which can be expressed as the quantitative change in cerebral blood flow (CBF) per mm Hg change in end-tidal partial pressure of CO2 (PETCO2). We investigate whether different respiratory manipulations, with arterial spin labeling used to measure CBF, lead to consistent measures of CVR. The approaches included: (1) an automated system delivering variable concentrations of inspired CO2 for prospective targeting of PETCO2, (2) administration of a fixed concentration of CO2 leading to subject-dependent changes in PETCO2, (3) a breath-hold (BH) paradigm with physiologic modeling of CO2 accumulation, and (4) a maneuver combining breath-hold and hyperventilation. When CVR was expressed as the percent change in CBF per mm Hg change in PETCO2, methods 1 to 3 gave consistent results. The CVR values using method 4 were significantly lower. When CVR was expressed in terms of the absolute change in CBF (mL/100g per minute per mm Hg), greater discrepancies became apparent: methods 2 and 3 gave lower absolute CVR values compared with method 1, and the value obtained with method 4 was dramatically lower. Our findings indicate that care must be taken to ensure that CVR is measured over the linear range of the CBF-CO2 dose-response curve, avoiding hypocapnic conditions.

Hypercapnic cerebral vascular reactivity is decreased, in humans, during sleep compared with wakefulness

2003 ◽  
Vol 94 (6) ◽  
pp. 2197-2202 ◽  
Author(s):  
Guy E. Meadows ◽  
Helen M. A. Dunroy ◽  
Mary J. Morrell ◽  
Douglas R. Corfield
Keyword(s):  
Blood Flow ◽  
Vascular Reactivity ◽  
Nrem Sleep ◽  
Normal Subjects ◽  
Stage Iii ◽  
Left Middle Cerebral Artery ◽  
Cortical Blood Flow ◽  
Pulsed Doppler Ultrasound ◽  
End Tidal ◽  
Cerebral Vascular

During wakefulness, increases in the partial pressure of arterial CO2 result in marked rises in cortical blood flow. However, during stage III–IV, non-rapid eye movement (NREM) sleep, and despite a relative state of hypercapnia, cortical blood flow is reduced compared with wakefulness. In the present study, we tested the hypothesis that, in normal subjects, hypercapnic cerebral vascular reactivity is decreased during stage III–IV NREM sleep compared with wakefulness. A 2-MHz pulsed Doppler ultrasound system was used to measure the left middle cerebral artery velocity (MCAV; cm/s) in 12 healthy individuals while awake and during stage III–IV NREM sleep. The end-tidal Pco 2(Pet CO2 ) was elevated during the awake and sleep states by regulating the inspired CO2 load. The cerebral vascular reactivity to CO2 was calculated from the relationship between Pet CO2 and MCAV by using linear regression. From wakefulness to sleep, the Pet CO2 increased by 3.4 Torr ( P < 0.001) and the MCAV fell by 11.7% ( P < 0.001). A marked decrease in cerebral vascular reactivity was noted in all subjects, with an average fall of 70.1% ( P = 0.001). This decrease in hypercapnic cerebral vascular reactivity may, at least in part, explain the stage III–IV NREM sleep-related reduction in cortical blood flow.

Breath holding test in preeclampsia: lack of evidence for altered cerebral vascular reactivity

2002 ◽  
Vol 11 (3) ◽  
pp. 160-163 ◽  
Author(s):  
J. Zatik ◽  
J. Aranyosi ◽  
G. Settakis ◽  
D. PÁll ◽  
Z. Tóth ◽  
...  
Keyword(s):  
Vascular Reactivity ◽  
Breath Holding ◽  
Cerebral Vascular

Maximum effort breath-hold times for males and females of similar pulmonary capacities during sudden face-only immersion at water temperatures from 0 to 33 °C

2006 ◽  
Vol 31 (5) ◽  
pp. 549-556 ◽  
Author(s):  
Ollie Jay ◽  
Matthew D. White
Keyword(s):  
Water Temperature ◽  
Hold Time ◽  
Breath Holding ◽  
Breath Hold ◽  
Main Effect ◽  
Before And After ◽  
Maximum Effort ◽  
Males And Females ◽  
End Tidal ◽  
Air Control

For non breath-hold-trained males and females matched for pulmonary capacity and body size, the effects of sex, water temperature, and end-tidal gas tensions were studied for their potential influences on breath-holding ability. Maximum breath-hold time (BHTmax) was measured a total of 546 times in 13 males and 13 females, each repeating 3 trials of sudden face immersion (i.e., no prior hyperventilation) in water at 0, 5, 10, 15, 20, and 33 °C and in an air control condition (AIR). End-tidal carbon dioxide (PETCO2) and oxygen (PETO2) gas tensions were measured before and after breath-holding in a subset of 11 males and 11 females. For BHTmax there was no main effect of sex (p = 0.20), but there was a main effect of immersion condition (p < 0.001). Relative to pre-immersion rest values, end-tidal gas tensions were significantly higher in males than in females (p ≤ 0.05) and significantly lower at decreased water temperatures relative to AIR (p ≤ 0.05). In conclusion, for these matched groups (i) sex did not influence BHTmax; (ii) irrespective of sex, decreases in water temperature at 0, 5, 10, and 15 °C gave proportionate decreases of BHTmax; (iii) significantly greater deviations in both PETCO2 and PETO2 following breath-holding were evident in males relative to females; and (iv) irrespective of sex, there were significantly smaller changes in both PETCO2 and PETO2 at lower water temperatures relative to AIR, with or without removing the variance due to breath holding.

Central chemoreflex sensitivity and sympathetic neural outflow in elite breath-hold divers

2008 ◽  
Vol 104 (1) ◽  
pp. 205-211 ◽  
Author(s):  
Zeljko Dujic ◽  
Vladimir Ivancev ◽  
Karsten Heusser ◽  
Gordan Dzamonja ◽  
Ivan Palada ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Arterial Hypertension ◽  
Sympathetic Activity ◽  
Arterial Oxygen ◽  
System Response ◽  
Breath Holding ◽  
Breath Hold ◽  
Control Subjects ◽  
Obstructive Sleep ◽  
End Tidal

Repeated hypoxemia in obstructive sleep apnea patients increases sympathetic activity, thereby promoting arterial hypertension. Elite breath-holding divers are exposed to similar apneic episodes and hypoxemia. We hypothesized that trained divers would have increased resting sympathetic activity and blood pressure, as well as an excessive sympathetic nervous system response to hypercapnia. We recruited 11 experienced divers and 9 control subjects. During the diving season preceding the study, divers participated in 7.3 ± 1.2 diving fish-catching competitions and 76.4 ± 14.6 apnea training sessions with the last apnea 3–5 days before testing. We monitored beat-by-beat blood pressure, heart rate, femoral artery blood flow, respiration, end-tidal CO2, and muscle sympathetic nerve activity (MSNA). After a baseline period, subjects began to rebreathe a hyperoxic gas mixture to raise end-tidal CO2 to 60 Torr. Baseline MSNA frequency was 31 ± 11 bursts/min in divers and 33 ± 13 bursts/min in control subjects. Total MSNA activity was 1.8 ± 1.5 AU/min in divers and 1.8 ± 1.3 AU/min in control subjects. Arterial oxygen saturation did not change during rebreathing, whereas end-tidal CO2 increased continuously. The slope of the hypercapnic ventilatory and MSNA response was similar in both groups. We conclude that repeated bouts of hypoxemia in elite, healthy breath-holding divers do not lead to sustained sympathetic activation or arterial hypertension. Repeated episodes of hypoxemia may not be sufficient to drive an increase in resting sympathetic activity in the absence of additional comorbidities.

O5-01-01: Apoe E4 Allele Effect on Vascular Reactivity Measured by Breath-Hold Arterial Spin Labeling in Normal and Memory-Impaired Adults

2016 ◽  
Vol 12 ◽  
pp. P374-P375
Author(s):  
Megan E. Johnston ◽  
Laura D. Baker ◽  
Suzanne Craft ◽  
Christopher T. Whitlow ◽  
Youngkyoo Jung
Keyword(s):  
Arterial Spin Labeling ◽  
Vascular Reactivity ◽  
Spin Labeling ◽  
Breath Hold ◽  
Allele Effect ◽  
E4 Allele

scholarly journals Cerebral metabolism and vascular reactivity during breath-hold and hypoxic challenge in freedivers and healthy controls

2017 ◽  
Vol 39 (5) ◽  
pp. 834-848 ◽  
Author(s):  
Mark B Vestergaard ◽  
Henrik BW Larsson
Keyword(s):  
Blood Flow ◽  
Magnetic Resonance ◽  
Vascular Reactivity ◽  
Cerebral Metabolism ◽  
Lactate Production ◽  
Occipital Lobe ◽  
Cerebrovascular Reactivity ◽  
Breath Holding ◽  
Breath Hold ◽  
Resonance Spectroscopy

The goal of the present study was to examine the cerebral metabolism and vascular reactivity during extended breath-holds (ranging from 2 min 32 s to 7 min 0 s) and during a hypoxic challenge in freedivers and non-diver controls. Magnetic resonance imaging was used to measure the global cerebral blood flow (CBF) and metabolic rate of oxygen (CMRO2), and magnetic resonance spectroscopy was used to measure the cerebral lactate, glutamate+glutamine, N-acetylaspartate and phosphocreatine+creatine concentrations in the occipital lobe. Fifteen freedivers and seventeen non-diver controls participated. The freedivers showed remarkable increases in CBF (107%) during the breath-holds, compensating for arterial desaturation, and sustained cerebral oxygen delivery (CDO2). CMRO2 was unaffected throughout the breath-holds. During the hypoxic challenge, the freedivers had larger increases in blood flow in the sagittal sinus than the non-divers, and could sustain normal CDO2. No differences were found in lactate production, global CBF or CMRO2. We conclude that the mechanism for sustaining brain function during breath-holding in freedivers involves an extraordinary increase in perfusion, and that freedivers present evidence for higher cerebrovascular reactivity, but not for higher lactate-producing glycolysis during a hypoxic challenge compared to controls.

scholarly journals Breath-Hold Induced Cerebrovascular Reactivity Measurements Using Optimized Pseudocontinuous Arterial Spin Labeling

2021 ◽  
Vol 12 ◽  
Author(s):  
Sergio M. Solis-Barquero ◽  
Rebeca Echeverria-Chasco ◽  
Marta Calvo-Imirizaldu ◽  
Elena Cacho-Asenjo ◽  
Antonio Martinez-Simon ◽  
...  
Keyword(s):  
Arterial Spin Labeling ◽  
Free Breathing ◽  
Physiological Model ◽  
Spin Labeling ◽  
Cerebrovascular Reactivity ◽  
Breath Holding ◽  
Breath Hold ◽  
Background Suppression ◽  
Single Shot ◽  
Scan Time

A pseudocontinuous arterial spin labeling (PCASL) sequence combined with background suppression and single-shot accelerated 3D RARE stack-of-spirals was used to evaluate cerebrovascular reactivity (CVR) induced by breath-holding (BH) in ten healthy volunteers. Four different models designed using the measured change in PETCO2 induced by BH were compared, for CVR quantification. The objective of this comparison was to understand which regressor offered a better physiological model to characterize the cerebral blood flow response under BH. The BH task started with free breathing of 42 s, followed by interleaved end-expiration BHs of 21 s, for ten cycles. The total scan time was 12 min and 20 s. The accelerated readout allowed the acquisition of PCASL data with better temporal resolution than previously used, without compromising the post-labeling delay. Elevated CBF was observed in most cerebral regions under hypercapnia, which was delayed with respect to the BH challenge. Significant statistical differences in CVR were obtained between the different models in GM (p &lt; 0.0001), with ramp models yielding higher values than boxcar models and between the two tissues, GM and WM, with higher values in GM, in all the models (p &lt; 0.0001). The adjustment of the ramp amplitude during each BH cycle did not improve the results compared with a ramp model with a constant amplitude equal to the mean PETCO2 change during the experiment.

scholarly journals Large Lung Volumes Delay the Onset of the Physiological Breaking Point During Simulated Diving

2021 ◽  
Vol 12 ◽  
Author(s):  
Paul F. McCulloch ◽  
B. W. Gebhart ◽  
J. A. Schroer
Keyword(s):  
Lung Volume ◽  
Blood Gases ◽  
Breaking Point ◽  
Breath Holding ◽  
Breath Hold ◽  
Lung Volumes ◽  
Arterial Blood ◽  
Face Immersion ◽  
Residual Capacity ◽  
End Tidal

During breath holding after face immersion there develops an urge to breathe. The point that would initiate the termination of the breath hold, the “physiological breaking point,” is thought to be primarily due to changes in blood gases. However, we theorized that other factors, such as lung volume, also contributes significantly to terminating breath holds during face immersion. Accordingly, nine naïve subjects (controls) and seven underwater hockey players (divers) voluntarily initiated face immersions in room temperature water at Total Lung Capacity (TLC) and Functional Residual Capacity (FRC) after pre-breathing air, 100% O2, 15% O2 / 85% N2, or 5% CO2 / 95% O2. Heart rate (HR), arterial blood pressure (BP), end-tidal CO2 (etCO2), and breath hold durations (BHD) were monitored during all face immersions. The decrease in HR and increase in BP were not significantly different at the two lung volumes, although the increase in BP was usually greater at FRC. BHD was significantly longer at TLC (54 ± 2 s) than at FRC (30 ± 2 s). Also, with each pre-breathed gas BHD was always longer at TLC. We found no consistent etCO2 at which the breath holding terminated. BDHs were significantly longer in divers than in controls. We suggest that during breath holding with face immersion high lung volume acts directly within the brainstem to actively delay the attainment of the physiological breaking point, rather than acting indirectly as a sink to produce a slower build-up of PCO2.

Effect of breath holding on cerebrovascular hemodynamics in normal pregnancy and preeclampsia

2015 ◽  
Vol 118 (7) ◽  
pp. 858-862 ◽  
Author(s):  
Teelkien R. van Veen ◽  
Ronney B. Panerai ◽  
Sina Haeri ◽  
Gerda G. Zeeman ◽  
Michael A. Belfort
Keyword(s):  
Cerebral Blood Flow Velocity ◽  
Cohort Analysis ◽  
Area Under The Curve ◽  
Resistance Index ◽  
Normal Pregnancy ◽  
Breath Holding ◽  
Control Group ◽  
Breath Hold ◽  
Area Product ◽  
End Tidal

Preeclampsia (PE) is associated with endothelial dysfunction and impaired autonomic function, which is hypothesized to cause cerebral hemodynamic abnormalities. Our aim was to test this hypothesis by estimating the difference in the cerebrovascular response to breath holding (BH; known to cause sympathetic stimulation) between women with preeclampsia and a group of normotensive controls. In a prospective cohort analysis, cerebral blood flow velocity (CBFV) in the middle cerebral artery (transcranial Doppler), blood pressure (BP, noninvasive arterial volume clamping), and end-tidal carbon dioxide (EtCO2) were simultaneously recorded during a 20-s breath hold maneuver. CBFV changes were broken down into standardized subcomponents describing the relative contributions of BP, cerebrovascular resistance index (CVRi), critical closing pressure (CrCP), and resistance area product (RAP). The area under the curve (AUC) was calculated for changes in relation to baseline values. A total of 25 preeclamptic (before treatment) and 25 normotensive women in the second half of pregnancy were enrolled, and, 21 patients in each group were included in the analysis. The increase in CBFV and EtCO2 was similar in both groups. However, the AUC for CVRi and RAP during BH was significantly different between the groups (3.05 ± 2.97 vs. −0.82 ± 4.98, P = 0.006 and 2.01 ± 4.49 vs. −2.02 ± 7.20, P = 0.037), indicating an early, transient increase in CVRi and RAP in the control group, which was absent in PE. BP had an equal contribution in both groups. Women with preeclampsia have an altered initial CVRi response to the BH maneuver. We propose that this is due to blunted sympathetic or myogenic cerebrovascular response in women with preeclampsia.

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