Division of Anaesthesia and Intensive Care, Department of Surgical, Medical, Molecular and Critical Care Area, University of Pisa, Via Paradisa 2, 56124, Pisa, Italy.
Sci Rep. 2022 Feb 28;12(1):3335. doi: 10.1038/s41598-022-07410-1.
Positive end-expiratory pressure (PEEP) may affect arterial wave propagation and reflection, thus influencing ventricular loading conditions. The aim of the study was to investigate the hemodynamic variations in arterial wave reflection (i.e., wave reflection time, augmentation index, left ventricular ejection time, diastolic time, SEVR) associated with the application of increasing levels of PEEP in healthy subjects. We conducted a prospective observational study. Study population was selected from students and staff. Pulse contour wave analysis was performed from the right carotid artery during stepwise increase in PEEP levels (from 0 cmHO, 5 cmH0, 10 cmHO) with applanation tonometry. Sixty-two healthy volunteers were recruited. There were no significant changes in heart rate, augmentation index (AIx), left ventricular ejection time, Diastolic time (DT) among all of the different steps. A significant increase of time to the inflection point (Ti) was observed during all steps of the study. Diastolic area under the curve (AUC) divided by systolic-AUC (SEVR) increased from baseline to PEEP = 5 cmHO, and from baseline to PEEP = 10 cmHO. AIx and Ti were significantly correlated (directly) at the baseline and during PEEP = 10 cmHO. Ti and DT were significantly correlated at the baseline and during PEEP = 5 cmHO. In our preliminary results, low levels of PEEP played a role in the interaction between the heart and the vascular system, apparently mediated by a prolongation of the diastolic phase and a reduction in the systolic work of the heart.Clinical trials registration number: NCT03294928, 19/09/2017.
呼气末正压 (PEEP) 可能会影响动脉波的传播和反射，从而影响心室的负荷状况。本研究旨在探讨健康受试者中应用递增水平的 PEEP 时动脉反射波（即反射波时间、增强指数、左心室射血时间、舒张时间、SEVR）的血流动力学变化。我们进行了一项前瞻性观察性研究。研究人群选自学生和工作人员。使用平板张力法，在逐步增加 PEEP 水平（从 0cmHO、5cmH0、10cmHO）的过程中，从右侧颈动脉进行脉搏轮廓波分析。共招募了 62 名健康志愿者。在所有不同的步骤中，心率、增强指数 (AIx)、左心室射血时间、舒张时间 (DT) 均无显著变化。在研究的所有阶段，拐点时间 (Ti) 均显著增加。从基础值到 PEEP = 5cmHO，以及从基础值到 PEEP = 10cmHO，舒张面积除以收缩面积 (SEVR) 增加。在基础值和 PEEP = 10cmHO 时，AIx 和 Ti 呈显著相关（直接相关）。在基础值和 PEEP = 5cmHO 时，Ti 和 DT 呈显著相关。在我们的初步结果中，低水平的 PEEP 在心脏和血管系统之间的相互作用中发挥了作用，显然是通过舒张期延长和心脏收缩做功减少来介导的。临床试验注册号：NCT03294928，2017 年 9 月 19 日。
