Travaline J M, Sudarshan S, Criner G J
Department of Medicine, Temple University School of Medicine, Philadelphia, Pennsylvania, USA.
Am J Respir Crit Care Med. 1997 Nov;156(5):1562-6. doi: 10.1164/ajrccm.156.5.9608030.
Low frequency diaphragm fatigue (LFF) may play a major role in the pathogenesis of ventilatory failure; however, recovery from LFF is not well studied. We measured transdiaphragmatic twitch pressure (PdiT) at FRC (using a reduction of PdiT as an index of LFF) and maximum transdiaphragmatic pressure (Pdimax) before and after the induction of diaphragm fatigue in seven normal subjects, age 31 +/- 3 yr (mean +/- SD). Fatigue was induced by breathing through an inspiratory resistive load. PdiT produced by bilateral transcutaneous supramaximal electrophrenic stimulation was measured at baseline, 15, 30 min, 1, 2, 3, 4 h, and then 1 to 3 times between hour 20-25 post-fatigue. Pdimax estimated by twitch occlusion was measured at baseline, 30 min, 2-3, and 20-25 h post-fatigue. Pre-fatigue values (mean +/- SE) were: PdiT 23.6 +/- 2.5 cm H2O. The mean +/- SD time to fatigue was 25.3 +/- 12.3 min. Post-fatigue PdiT was reduced to 50%, and by 3 h was 72% of the initial value; 100% by 25 h. Pdimax was reduced to 75% post-fatigue, but recovered to 87% by 3 h, and 100% by 25 h. We concluded that recovery of PdiT and Pdimax in normal subjects starts to occur within the first few hours following diaphragm fatigue, and is complete by 25 h.
低频膈肌疲劳（LFF）可能在通气衰竭的发病机制中起主要作用；然而，LFF的恢复情况尚未得到充分研究。我们在7名年龄为31±3岁（平均±标准差）的正常受试者中，于诱发膈肌疲劳前后，在功能残气量（FRC）时测量跨膈抽搐压力（PdiT）（以PdiT降低作为LFF指标）和最大跨膈压力（Pdimax）。通过吸气阻力负荷呼吸诱发疲劳。在基线、15、30分钟、1、2、3、4小时，然后在疲劳后20 - 25小时之间测量1至3次，测量双侧经皮超最大电刺激产生的PdiT。通过抽搐闭塞估计的Pdimax在基线、疲劳后30分钟、2 - 3小时和20 - 25小时测量。疲劳前的值（平均±标准误）为：PdiT 23.6±2.5 cm H2O。达到疲劳的平均±标准差时间为25.3±12.3分钟。疲劳后PdiT降至初始值的50%，3小时时为72%；25小时时为100%。Pdimax在疲劳后降至75%，但3小时时恢复至87%，25小时时恢复至100%。我们得出结论，正常受试者中PdiT和Pdimax的恢复在膈肌疲劳后的最初几个小时内开始出现，并在25小时时完全恢复。
