Department of Intensive Care and Anaesthesia, Catholic University of Rome, Policlinico Agostino Gemelli, Largo F.Vito 1, 00168 Rome, Italy.
Intensive Care Med. 2011 Sep;37(9):1494-500. doi: 10.1007/s00134-011-2297-y. Epub 2011 Jul 1.
To compare patient-ventilator interaction during PSV and PAV+ in patients that are difficult to wean.
This was a physiologic study involving 11 patients. During three consecutive trials (PSV first trial--PSV1, followed by PAV+, followed by a second PSV trial--PSV2, with the same settings as PSV1) we evaluated mechanical and patient respiratory pattern; inspiratory effort from excursion Pdi (swing(Pdi)), and pressure-time products of the transdiaphragmatic (PTPdi) pressures. Inspiratory (delay(trinsp)) and expiratory (delay(trexp)) trigger delays, time of synchrony (time(syn)), and asynchrony index (AI) were assessed.
Compared to PAV+, during PSV trials, the mechanical inspiratory time (Ti(flow)) was significantly longer than patient inspiratory time (Ti(pat)) (p < 0.05); Ti(pat) showed a prolongation between PSV1 and PAV+, significant comparing PAV+ and PSV2 (p < 0.05). PAV+ significantly reduced delay(trexp) (p < 0.001). The portion of tidal volume (VT) delivered in phase with Ti(pat) (VT(pat)/VT(mecc)) was significantly higher during PAV+ (p < 0.01). The time of synchrony was significantly longer during PAV+ than during PSV (p < 0.001). During PSV 5 patients out of 11 showed an AI greater than 10%, whereas the AI was nil during PAV+.
PAV+ improves patient-ventilator interaction, significantly reducing the incidence of end-expiratory asynchrony and increasing the time of synchrony.
比较 PSV 和 PAV+在撤机困难患者中患者-呼吸机的相互作用。
这是一项涉及 11 例患者的生理学研究。在连续三次试验（首先进行 PSV 试验-PSV1，随后进行 PAV+，然后进行第二次 PSV 试验-PSV2，设置与 PSV1 相同）中，我们评估了机械通气和患者呼吸模式；从呼气末漂移（swing(Pdi)）评估吸气努力（Pdi 摆动(Pdi)）和跨膈压（PTPdi）压力的压力-时间乘积。评估了吸气（延迟(trinsp))和呼气（延迟(trexp))触发延迟、同步时间（time(syn))和失步指数（AI)。
与 PAV+相比，PSV 试验中机械吸气时间（Ti(flow)）明显长于患者吸气时间（Ti(pat))（p < 0.05）；Ti(pat)在 PSV1 和 PAV+之间延长，PAV+和 PSV2 之间差异有统计学意义（p < 0.05）。PAV+显著降低了延迟(trexp)（p < 0.001）。与 Ti(pat)同步输送的潮气量（VT(pat)/VT(mecc))部分在 PAV+时明显更高（p < 0.01）。同步时间在 PAV+时明显长于 PSV（p < 0.001）。在 PSV 中，11 例患者中有 5 例 AI 大于 10%，而在 PAV+时 AI 为零。
PAV+改善了患者-呼吸机的相互作用，显著降低了呼气末失步的发生率，增加了同步时间。
