Effect of acute hypoxemia on cerebral blood flow velocity control during lower body negative pressure
Effect of acute hypoxemia on cerebral blood flow velocity control during lower body negative pressure
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DOI：
10.14814/phy2.13594
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发表时间：
2018-02-01
影响因子：
2.5
通讯作者：
Joyner, Michael J.
中科院分区：
文献类型：
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作者：
van Helmond, Noud;Johnson, Blair D.;Joyner, Michael J.
维持足够的脑血流量和氧合的能力决定了对中枢性低血容量的耐受性。我们测试了一个假设，即人类在模拟失血过程中急性低氧血症会导致脑血流控制受损。10名健康受试者（32 +/- 6岁，BMI 27 +/- 2 kg.m(-2)）在常氧和低氧条件下（FiO2 = 0.12-0.15 O-2, SaO(2)接近85%）逐步暴露于下体负压（LBNP，在0、-15、-30和-45 mmHg下5分钟）。两种方案中的生理反应均表示为与基线的绝对变化，一名受试者因缺氧时LBNP第一阶段的晕厥前兆而被排除在分析之外。低氧状态下，LBNP诱导的平均动脉压下降幅度大于缺氧状态下（MAP, -45 mmHg）： -20 +/- 3 vs -5 +/- 3 mmHg
The ability to maintain adequate cerebral blood flow and oxygenation determines tolerance to central hypovolemia. We tested the hypothesis that acute hypoxemia during simulated blood loss in humans would cause impairments in cerebral blood flow control. Ten healthy subjects (32 +/- 6 years, BMI 27 +/- 2 kg.m(-2)) were exposed to stepwise lower body negative pressure (LBNP, 5 min at 0, -15, -30, and -45 mmHg) during both normoxia and hypoxia (FiO2 = 0.12-0.15 O-2 titrated to an SaO(2) of similar to 85%). Physiological responses during both protocols were expressed as absolute changes from baseline, one subject was excluded from analysis due to presyncope during the first stage of LBNP during hypoxia. LBNP induced greater reductions in mean arterial pressure during hypoxia versus normoxia (MAP, at -45 mmHg: -20 +/- 3 vs. -5 +/- 3 mmHg, P