State Key Laboratory of Respiratory Disease, National Clinical Research Center for Respiratory Disease, Guangzhou Institute of Respiratory Health, Guangzhou, China and with The First Affiliated Hospital of Guangzhou Medical University, Guangzhou, China.
Respir Care. 2020 Jan;65(1):45-52. doi: 10.4187/respcare.06430. Epub 2019 Sep 24.
To investigate patient-ventilator interaction during different levels of noninvasive proportional assist ventilation (PAV) compared with noninvasive pressure support ventilation (PSV).
Fifteen subjects with severe COPD and hypercapnia were consecutively recruited. After the baseline assessment of unassisted spontaneous breathing, 3 levels of ventilatory support were applied. The proportional assist (PA) and pressure support (PS) levels were set by subject comfort. PA-, PS- or PA+, PS+ were set at 25% more or less of PA or PS (PA- = 75% PA, PA+ = 125% PA, PS- = 75% PS, PS+ = 125% PS). Each level lasted at least 20 min. To demonstrate the patient-ventilator interaction, the neural respiratory drive, respiratory muscle effort, flow signal, and airway pressure were simultaneously monitored.
The expiratory cycle delay (time between the termination of the diaphragm electromyogram [EMG] signal and the end of the inspiratory flow) progressively increased with increasing assist level in both modes. However, compared with PSV, the expiratory cycle delay was significantly longer in each assist level during noninvasive PAV. The runaway phenomenon was observed in PA+. The time between the peak EMG signal and the maximum value of the flow signal and the time difference between the peak EMG signal and the maximum value of inspiratory pressure were significantly increased with the increasing assist level of PAV.
The expiratory cycle delay of noninvasive PAV was significantly longer than that of noninvasive PSV in the subjects with COPD with respiratory failure. During the levels of PAV, the lag time between neural respiratory drive and airway pressurization was significantly increased and the "runaway" phenomenon may be observed. (ClinicalTrials.gov registration NCT01782768.).
研究不同水平的无创比例辅助通气（PAV）与无创压力支持通气（PSV）期间患者与呼吸机的相互作用。
连续招募了 15 名患有严重 COPD 和高碳酸血症的患者。在未辅助自主呼吸的基线评估后，应用了 3 种通气支持水平。通过患者舒适度设置比例辅助（PA）和压力支持（PS）水平。PA-、PS-或 PA+、PS+设置为 PA 或 PS 的 25%增减（PA-=75%PA、PA+=125%PA、PS-=75%PS、PS+=125%PS）。每个水平至少持续 20 分钟。为了展示患者与呼吸机的相互作用，同时监测神经呼吸驱动、呼吸肌努力、流量信号和气道压力。
在两种模式下，随着辅助水平的增加，呼气周期延迟（膈肌肌电图[EMG]信号终止与吸气流量结束之间的时间）逐渐增加。然而，与 PSV 相比，在无创 PAV 的每个辅助水平下，呼气周期延迟都明显更长。在 PA+中观察到失控现象。峰值 EMG 信号与流量信号最大值之间的时间以及峰值 EMG 信号与吸气压力最大值之间的时间差随着 PAV 的辅助水平增加而显著增加。
在患有呼吸衰竭的 COPD 患者中，无创 PAV 的呼气周期延迟明显长于无创 PSV。在 PAV 水平期间，神经呼吸驱动与气道加压之间的滞后时间显著增加，并且可能观察到“失控”现象。（ClinicalTrials.gov 注册号 NCT01782768.）。
