Ramsdell J W, Georghiou P F
J Appl Physiol Respir Environ Exerc Physiol. 1979 Aug;47(2):418-24. doi: 10.1152/jappl.1979.47.2.418.
We studied the effect of prolonged airways obstruction induced by extended cholinergic stimulation in five anesthetized, mechanically ventilated dogs. A continuous intravenous metacholine infusion was utilized to maintain pulmonary resistance (RL) at 200--1500% preinfusion levels for 13--23 h. At maximum RL (18.86 +/- 7.74 vs. 2.09 +/- 0.18 (mean +/- SD) cmH2O/ (L/S) PREINfusion; P less than 0.01), dynamic lung compliance (Cdyn) fell from 67.5 +/- 14.6 to 32.7 +/- 11.6 ml/cmH2O (P less than 0.005) and arterial partial pressure of oxygen (PaO2) fell modestly from 95.8 +/- 6.1 Torr preinfusion to 83.2 +/- 12.7 Torr (P less than 0.05). Tachyphylaxis to methacholine developed, requiring increases in infusion rates to maintain elevated RL. Abnormalities in lung function resolved promptly upon termination of the infusion. Two similarly instrumented control animals ventilated for 19 and 25 h without metacholine infusion had no change in RL, Cdyn, or PaO2. Histological examination of the lungs revealed no differences between infused and control animals. In spite of marked increases in RL, prolonged cholinergic stimulation produced only mild changes in gas exchange and no sustained changes in lung function or structure.
我们研究了在五只麻醉、机械通气的犬中，延长胆碱能刺激诱导的长时间气道阻塞的影响。通过持续静脉输注乙酰甲胆碱，将肺阻力（RL）维持在输注前水平的200%-1500%达13-23小时。在最大RL时（18.86±7.74对2.09±0.18（均值±标准差）cmH2O/（L/S）输注前；P<0.01），动态肺顺应性（Cdyn）从67.5±14.6降至32.7±11.6 ml/cmH2O（P<0.005），动脉血氧分压（PaO2）从输注前的95.8±6.1 Torr适度降至83.2±12.7 Torr（P<0.05）。对乙酰甲胆碱产生了快速减敏反应，需要提高输注速率以维持升高的RL。输注终止后，肺功能异常迅速缓解。两只同样插管的对照动物在未输注乙酰甲胆碱的情况下通气19和25小时，RL、Cdyn或PaO2无变化。肺组织学检查显示输注组和对照组动物之间无差异。尽管RL显著增加，但延长的胆碱能刺激仅引起气体交换的轻微变化，且未导致肺功能或结构的持续改变。
