Hambraeus-Jonzon K, Bindslev L, Mellgård A J, Hedenstierna G
Department of Anesthesia and Intensive Care, Karolinska Hospital, Stockholm, Sweden.
Anesthesiology. 1997 Feb;86(2):308-15. doi: 10.1097/00000542-199702000-00006.
A stimulus-response relation between alveolar oxygen tension and pulmonary vascular resistance has been observed in animals. This study investigated this relation in healthy human lungs. The distribution of pulmonary blood flow was measured during unilateral (1) graded hypoxia (fractional concentration of oxygen in inspired gas [FIO2] = 0.12, 0.08, and 0.05) and contralateral hyperoxia (FIO2 = 1.0; n = 6); (2) single-step hypoxia (FIO2 = 0.05) and contralateral hyperoxia (n = 5); and (3) normobaric hyperoxia and contralateral normoxia (FIO2 = 0.25; n = 6).
Seventeen patients with healthy lungs were studied during intravenous anesthesia. The lungs were separately and synchronously ventilated. The relative perfusion of each lung was assessed by the inert gas (sulfurhexafluoride) elimination technique.
(1) Unilateral graded hypoxia reduced the perfusion of the hypoxic lung from a mean (+/-SD) of 52 (2)% of cardiac output (Q) during bilateral hyperoxia, to 47 (5)% (P > 0.05) 40 (3)% (P < 0.01), and 30 (8)% (P < 0.001) of Q, respectively. These progressive reductions in the perfusion of the hypoxic lung were all significantly different from each other. (2) Unilateral single-step hypoxia caused a blood flow diversion of the same magnitude as when the lung was previously ventilated with FiO2 of 0.12 and 0.08. The perfusion of the hypoxic lung was reduced from 46 (9)% of Q (bilateral hyperoxia) to 26 (4)% of Q (P < 0.01). (3) Unilateral hyperoxia did not significantly change the relative blood flow distribution between the two lungs or the pulmonary artery pressure.
A stimulus-response relation between graded hypoxia and blood flow diversion defines hypoxic pulmonary vasoconstriction in the normal human lung. Hyperoxia has no significant effect on vascular resistance in the normal human lung.
在动物实验中已观察到肺泡氧分压与肺血管阻力之间存在刺激 - 反应关系。本研究旨在探究健康人肺中的这种关系。在单侧（1）分级低氧（吸入气体中氧的分数浓度[FIO₂]=0.12、0.08和0.05）及对侧高氧（FIO₂ = 1.0；n = 6）；（2）单步低氧（FIO₂ = 0.05）及对侧高氧（n = 5）；（3）常压高氧及对侧常压（FIO₂ = 0.25；n = 6）的情况下测量肺血流分布。
对17例肺功能正常的患者在静脉麻醉期间进行研究。双肺分别且同步通气。通过惰性气体（六氟化硫）清除技术评估每侧肺的相对灌注情况。
（1）单侧分级低氧使低氧肺的灌注从双侧高氧时的心输出量（Q）的平均（±标准差）52（2）%，分别降至47（5）%（P>0.05）、40（3）%（P<0.01）和30（8）%（P<0.001）。低氧肺灌注的这些逐渐降低彼此间均有显著差异。（2）单侧单步低氧引起的血流分流幅度与该肺先前用FIO₂为0.12和0.08通气时相同。低氧肺的灌注从Q的46（9）%（双侧高氧）降至Q的26（4）%（P<0.01）。（3）单侧高氧未显著改变双肺之间的相对血流分布或肺动脉压力。
分级低氧与血流分流之间的刺激 - 反应关系定义了正常人肺中的低氧性肺血管收缩。高氧对正常人肺血管阻力无显著影响。
