Jonk Amy M, van den Berg Irene P, Olfert I Mark, Wray D Walter, Arai Tatsuya, Hopkins Susan R, Wagner Peter D
Department of Medicine, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093-0623, USA.
J Physiol. 2007 Mar 15;579(Pt 3):909-21. doi: 10.1113/jphysiol.2006.120949. Epub 2007 Jan 11.
Acetazolamide (ACZ) is used to prevent acute mountain sickness at altitude. Because it could affect O2 transport in several different and potentially conflicting ways, we examined its effects on pulmonary and muscle gas exchange and acid-base status during cycle exercise at approximately 30, 50 and 90% VO2max in normoxia (F(IO2) = 0.2093) and acute hypoxia (F(IO2) = 0.125). In a double-blind, order-balanced, crossover design, six healthy, trained men (normoxic VO2max= 59 ml kg(-1) min(-1)) exercised at both F(IO2) values after ACZ (3 doses of 250 mg, 8 h apart) and placebo. One week later this protocol was repeated using the other drug (placebo or ACZ). We measured cardiac output (QT), leg blood flow (LBF), and muscle and pulmonary gas exchange, the latter using the multiple inert gas elimination technique. ACZ did not significantly affect VO2, QT, LBF or muscle gas exchange. As expected, ACZ led to lower arterial and venous blood [HCO3-], pH and lactate levels (P < 0.05), and increased ventilation (P < 0.05). In both normoxia and hypoxia, ACZ resulted in higher arterial P(O2) and saturation and a lower alveolar-arterial P(O2) difference (AaD(O2)) due to both less VA/Q mismatch and less diffusion limitation (P < 0.05). In summary, ACZ improved arterial oxygenation during exercise, due to both greater ventilation and more efficient pulmonary gas exchange. However, muscle gas exchange was unaffected.
乙酰唑胺（ACZ）用于预防高原急性高山病。由于它可能以几种不同且潜在相互矛盾的方式影响氧气运输，我们研究了在常氧（F(IO2)=0.2093）和急性低氧（F(IO2)=0.125）条件下，在约30%、50%和90%最大摄氧量（VO2max）进行自行车运动时，其对肺和肌肉气体交换以及酸碱状态的影响。在一项双盲、顺序平衡、交叉设计中，六名健康、受过训练的男性（常氧VO2max = 59 ml·kg⁻¹·min⁻¹）在服用ACZ（3剂250 mg，间隔8小时）和安慰剂后，在两种F(IO2)值下进行运动。一周后，使用另一种药物（安慰剂或ACZ）重复该方案。我们测量了心输出量（QT）、腿部血流量（LBF）以及肌肉和肺气体交换，后者采用多惰性气体消除技术。ACZ对VO2、QT、LBF或肌肉气体交换没有显著影响。正如预期的那样，ACZ导致动脉血和静脉血[HCO3⁻]、pH值和乳酸水平降低（P < 0.05），通气增加（P < 0.05）。在常氧和低氧条件下，由于通气/血流（VA/Q）不匹配减少和扩散限制减少，ACZ导致动脉血氧分压（P(O2)）和饱和度升高，肺泡 - 动脉血氧分压差（AaD(O2)）降低（P < 0.05）。总之，ACZ在运动期间改善了动脉氧合，这是由于通气增加和肺气体交换更高效。然而，肌肉气体交换未受影响。
