Normo- and hypobaric hypoxia: are there any physiological differences?
Normo- and hypobaric hypoxia: are there any physiological differences?
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DOI：
10.1007/s00421-002-0789-8
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发表时间：
2003-04-01
影响因子：
3
通讯作者：
Travers, S
中科院分区：
文献类型：
--
作者：
Savourey, G;Launay, JC;Travers, S
自Bert（1878）和Barcroft（1925）以来，对缺氧的研究是通过降低大气压力（低压缺氧HH）或通过降低O-2分数（常压缺氧NH）来降低环境O-2分压（PO 2）。今天，一个问题仍然是有争议的：“是否有任何生理差异之间的HH和NH相同的环境PO 2？“由于发表的研究很少且有争议，我们随机选择了18名受试者，在环境PO 2等于120 hPa（4500 m）的条件下进行40分钟HH测试和40分钟NH测试。在整个测试过程中测量了呼吸频率（f）、潮气量（V-1）、每分钟通气量（WE）、Q和CO2潮气末分数或压力（分别为FETO和FETCO 2或PETO 2和PETCO 2）、心率（HR）和脉搏血氧饱和度（SpO（2））。在试验结束时，采集动脉血样，测量动脉血气O-2和CO2动脉分压（Pa-O2和Pa-CO2）、pH和O-2动脉饱和度（Sa（O2））。结果表明，与NH相比，HH期间f更大（P ≤ 0.001），BTPS条件下的V-1和V-E更低（P ≤ 0.05），FETO 2和FFTCO 2更高（P ≤ 0.05）。然而，PETO 2在测试的最后25分钟期间没有变化，并且PETCO 2在整个测试期间也没有变化。HH组HR高于NH组（P ≤ 0.05），SPO 2低于NH组（P ≤ 0.05）。动脉血数据显示，与NH相比，HH中的低氧血症、低碳酸血症和血液透析更严重，Sa（O2）更低（P！0.05）。它的结论是，生理反应的人提交到急性缺氧在P-O2等于120百帕不同，根据缺氧的类型。与NH相比，HH导致更大的低氧血症、低碳酸血症、血液透析和更低的动脉血氧饱和度。这些生理差异可能是死腔通气增加的结果，可能与气压降低有关，并可归为“对低压缺氧的特异性反应”。了解这种特定的反应可以提高未来对高原疾病的理解，预防和治疗。
Since Bert (1878) and Barcroft (1925), studies on hypoxia are realized by lowering ambient O-2 partial pressure (PO2) either by barometric pressure reduction (hypobaric hypoxia HH) or by lowering the O-2 fraction (normobaric hypoxia NH). Today, a question is still debated: "are there any physiological differences between HH and NH for the same ambient PO2?" Since published studies are scarce and controversial, we submitted 18 subjects in a random order to a 40-min HH test and to a 40-min NH test at an ambient PO2 equal to 120 hPa (4500 m). Cardioventilatory variables [breathing frequency (f), tidal volume (V-1,), minute ventilation WE), Q, and CO2 end-tidal fractions or pressures (FETO and FETCO2 or PETO2 and PETCO2 respectively), heart rate (HR) and O-2 arterial saturation by pulse oxymetry (SpO(2))] were measured throughout the tests. At the end of the tests, arterial blood samples were taken to measure arterial blood gases O-2 and CO2 arterial partial pressures (Pa-O2 and Pa-CO2), pH and O-2 arterial saturation (Sa(O2))]. Results show that during HH compared to NH, f is greater (P less than or equal to 0.001), V-1 and V-E under BTPS conditions are lower (P less than or equal to 0.05), and FETO2 and FFTCO2 are higher (P less than or equal to 0.05). However, PETO2 does not change during the last 25 min of the tests, and neither does PETCO2 throughout the tests. HR is higher (P less than or equal to 0.05) and SPO2 lower (P less than or equal to 0.05) in HH compared to NH. Arterial blood data reveal that hypoxemia, hypocapnia and blood alkalosis are greater in HH compared to NH and that Sa(O2) is lower (P ! 0.05). It is concluded that the physiological responses of humans submitted to an acute hypoxia at a P-O2 equal to 120 hPa differ according to the type of hypoxia. Compared to NH, HH leads to a greater hypoxemia, hypocapnia, blood alkalosis and a lower O-2 arterial saturation. These physiological differences could be the consequence of an increase in dead space ventilation, probably related to the barometric pressure reduction, and could be grouped together under the term "the specific response to hypobaric hypoxia". Knowledge of this specific response could improve the comprehension, prevention and treatment of altitude illnesses in the future.