Cycling of inspiratory and expiratory muscle groups with the ventilator in airflow limitation
Cycling of inspiratory and expiratory muscle groups with the ventilator in airflow limitation
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DOI：
10.1164/ajrccm.158.5.9802014
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发表时间：
1998-11-01
影响因子：
24.7
通讯作者：
Tobin, MJ
中科院分区：
文献类型：
--
作者：
Parthasarathy, S;Jubran, A;Tobin, MJ
对患者-呼吸机相互作用的研究主要集中在吸气事件上，对呼气事件的关注很少。我们试图确定呼气肌活动的时间和大小在导致患者-呼吸机不同步中的重要性。我们的研究是在接受压力支持的健康受试者中完成的，在受试者中，我们用Starling电阻诱导气流受限。呼气肌活动的时间和大小通过导线肌电记录腹横肌的活动获得，并与呼吸机循环和吸气肌活动分别由流量示踪和横隔肌肌电(EMG)确定的进行比较。气流受限的诱导在受试者的呼气肌群和机器的骑行中产生了显著的相位差异。一些吸气努力未能触发呼吸机，部分原因是在机械充气停止之前开始呼气努力导致弹性后坐增加。呼气肌肉放松的延迟并不影响随后的吸气努力触发呼吸机的成功。我们还研究了两种区分呼气肌肉活动和弹性反冲对呼气末内源性正压(PEEPi)贡献的准确性：呼气时胃压升高(PGA)与腹侧肌电活动的相关性更好(r=0.7~0.95)，而PGA早期吸气时的降低(r=0.04~0.53)。总而言之，持续机械充气进入神经呼气与随后的吸气尝试触发呼吸机失败有关。
Research on patient-ventilator interactions has largely focused on inspiratory events, with little attention paid to expiration. We sought to determine the importance of the timing and magnitude of expiratory muscle activity in causing patient-ventilator dyssynchrony. Our study was done with healthy subjects receiving pressure support in whom we induced airflow limitation with a Starling resistor. The timing and magnitude of expiratory muscle activity were obtained by wire electromyographic recording of the activity of the transversus abdominis muscle, and were compared with the cycling of the ventilator and inspiratory muscle activity as determined from a flow tracing and diaphragmatic electromyogram (EMG), respectively. Induction of airflow limitation produced significant phase differences in the cycling of the subjects' expiratory muscle group and that of the machine. Some inspiratory efforts failed to trigger the ventilator, owing in part to an increase in elastic recoil consequent to the commencement of expiratory efforts before the termination of mechanical inflation. A delay in relaxation of the expiratory muscles did not interfere with the success of subsequent inspiratory efforts to trigger the ventilator. We also investigated the accuracy of two approaches for distinguishing between the contributions of expiratory muscle activity and elastic recoil to intrinsic positive end-expiratory pressure (PEEPi): the expiratory increase in gastric pressure (Pga) correlated better with transversus abdominis electromyographic activity (r = 0.7 to 0.95) than did the early inspiratory decrease in Pga (r = 0.04 to 0.53). In conclusion, the continuation of mechanical inflation into neural expiration was associated with failure of the subsequent inspiratory attempt to trigger the ventilator.