Berg B W, Dillard T A, Derderian S S, Rajagopal K R
Department of Medicine, Walter Reed Army Medical Center, Washington, D.C. 20307-5001.
Am J Med. 1993 Apr;94(4):407-12. doi: 10.1016/0002-9343(93)90152-f.
Cardiovascular events are the leading cause of death during air travel. Because patients with chronic obstructive pulmonary disease (COPD) develop severe hypoxemia at altitude, we sought to determine whether changes in systemic hemodynamics may contribute to health risks during hypobaric hypoxia.
We recorded radial artery catheter blood pressure, cardiac frequency, and cardiac ectopy in 18 men (aged 68 +/- 6 years, mean +/- SD) with severe COPD (forced expiratory volume in 1 second 0.97 L +/- 0.32 L) at sea level, after 45 minutes of steady-state hypobaric hypoxia at 2,438 m in a hypobaric chamber, and after oxygen supplementation at 2,438 m.
Mean arterial pressure (mm Hg), systolic blood pressure (SBP), diastolic blood pressure, and pulsus paradoxus during acute hypobaric exposure did not differ from baseline. During oxygen supplementation, SBP declined (p = 0.028). Decreases in pulsus paradoxus and pulse pressure were noted on oxygen (p < 0.05). We found no changes in cardiac frequency. Cardiac ectopy was uncommon; for one subject, ectopy increased with hypobaric hypoxia and decreased with oxygen administration.
Vasopressor responses to hypoxia do not add to the risk of air travel in patients with severe COPD. Supplemental oxygen may cause beneficial hemodynamic changes in patients with COPD during acute hypobaric exposure.
心血管事件是航空旅行期间的主要死亡原因。由于慢性阻塞性肺疾病（COPD）患者在高空会出现严重低氧血症，我们试图确定全身血流动力学变化是否会导致低压缺氧期间的健康风险。
我们记录了18名重度COPD男性患者（年龄68±6岁，均值±标准差）在海平面、在低压舱内2438米处进行45分钟稳态低压缺氧后以及在2438米处补充氧气后的桡动脉导管血压、心率和心脏异位搏动情况。这些患者的一秒用力呼气量为0.97升±0.32升。
急性低压暴露期间的平均动脉压（毫米汞柱）、收缩压（SBP）、舒张压和奇脉与基线无差异。补充氧气期间，收缩压下降（p = 0.028）。补充氧气时奇脉和脉压降低（p < 0.05）。我们发现心率无变化。心脏异位搏动不常见；一名受试者的异位搏动在低压缺氧时增加，吸氧时减少。
对缺氧的血管加压反应不会增加重度COPD患者航空旅行的风险。在急性低压暴露期间，补充氧气可能会使COPD患者产生有益的血流动力学变化。
