Shen X, Gunst S J, Tepper R S
Department of Pediatrics, Indiana University School of Medicine, Indianapolis, Indiana 46223, USA.
J Appl Physiol (1985). 1997 Oct;83(4):1202-8. doi: 10.1152/jappl.1997.83.4.1202.
We evaluated the effects of the rate and volume of tidal ventilation on airway resistance (Raw) during intravenous methacholine (MCh) challenge in mechanically ventilated rabbits. Five rabbits were challenged at tidal volumes of 5, 10, and 20 ml/kg at a frequency of 15 breaths/min and also under static conditions (0 ml/kg tidal volume). Four rabbits were subjected to MCh challenge at frequencies of 6 and 30 breaths/min with a tidal volume of 10 ml/kg and also under static conditions. In both groups, the increase in Raw with MCh challenge was significantly greater under static conditions than during tidal ventilation at any frequency or volume. Increases in the volume or frequency of tidal ventilation resulted in significant decreases in Raw in response to MCh. We conclude that tidal breathing suppresses airway responsiveness in rabbits in vivo. The suppression of narrowing in response to MCh increases as the magnitude of the volume or the frequency of the tidal oscillations is increased. Our findings suggest that the effect of lung volume changes on airway responsiveness in vivo is primarily related to the stretch of airway smooth muscle.
我们评估了在机械通气的兔子静脉注射乙酰甲胆碱（MCh）激发试验期间，潮气量通气的速率和容量对气道阻力（Raw）的影响。五只兔子在潮气量分别为5、10和20 ml/kg、频率为15次/分钟的情况下接受激发试验，同时也在静态条件下（潮气量0 ml/kg）进行试验。四只兔子在潮气量为10 ml/kg、频率分别为6次/分钟和30次/分钟的情况下接受MCh激发试验，同样也在静态条件下进行试验。在两组试验中，MCh激发试验导致的Raw增加在静态条件下显著大于任何频率或容量的潮气量通气期间。潮气量通气的容量或频率增加导致对MCh反应的Raw显著降低。我们得出结论，潮式呼吸在体内抑制兔子的气道反应性。随着潮气量振荡的幅度或频率增加，对MCh反应的狭窄抑制作用增强。我们的研究结果表明，肺容积变化对体内气道反应性的影响主要与气道平滑肌的拉伸有关。
