Open lung approach versus standard protective strategies: Effects on driving pressure and ventilatory efficiency during anesthesia - A pilot, randomized controlled trial

Fernando Suarez-Sipmann,Esther Romero,Francisco J Belda,Ana Mugarra,Natividad Pozo,Blanca Arocas,Estefania Gracia,Gerardo Tusman,Marina Soro,Irene León,Carlos Ferrando

doi:10.1371/journal.pone.0177399

Abstract

BackgroundLow tidal volume (VT) during anesthesia minimizes lung injury but may be associated to a decrease in functional lung volume impairing lung mechanics and efficiency. Lung recruitment (RM) can restore lung volume but this may critically depend on the post-RM selected PEEP. This study was a randomized, two parallel arm, open study whose primary outcome was to compare the effects on driving pressure of adding a RM to low-VT ventilation, with or without an individualized post-RM PEEP in patients without known previous lung disease during anesthesia.MethodsConsecutive patients scheduled for major abdominal surgery were submitted to low-VT ventilation (6 ml·kg-1) and standard PEEP of 5 cmH2O (pre-RM, n = 36). After 30 min estabilization all patients received a RM and were randomly allocated to either continue with the same PEEP (RM-5 group, n = 18) or to an individualized open-lung PEEP (OL-PEEP) (Open Lung Approach, OLA group, n = 18) defined as the level resulting in maximal Cdyn during a decremental PEEP trial. We compared the effects on driving pressure and lung efficiency measured by volumetric capnography.ResultsOL-PEEP was found at 8±2 cmH2O. 36 patients were included in the final analysis. When compared with pre-RM, OLA resulted in a 22% increase in compliance and a 28% decrease in driving pressure when compared to pre-RM. These parameters did not improve in the RM-5. The trend of the DP was significantly different between the OLA and RM-5 groups (p = 0.002). VDalv/VTalv was significantly lower in the OLA group after the RM (p = 0.035).ConclusionsLung recruitment applied during low-VT ventilation improves driving pressure and lung efficiency only when applied as an open-lung strategy with an individualized PEEP in patients without lung diseases undergoing major abdominal surgery.Trial registrationClinicalTrials.gov NCT02798133

Highlights

Protective mechanical ventilation during anesthesia aims at minimizing lung injury and its inflammatory response, and has been associated to a decrease in postoperative pulmonary complications (PPCs) [1,2,3]
OL-positive end-expiratory pressure (PEEP) was found at 8±2 cmH2O. 36 patients were included in the final analysis
When compared with pre-RM, open lung approach (OLA) resulted in a 22% increase in compliance and a 28% decrease

Summary

Introduction

Protective mechanical ventilation during anesthesia aims at minimizing lung injury and its inflammatory response, and has been associated to a decrease in postoperative pulmonary complications (PPCs) [1,2,3]. The effects of a fixed PEEP with or without RM are not clearly beneficial, and according to data coming from post-hoc analysis including a large number of patients ventilated during anesthesia, appear to be protective only when associated to a decrease in driving pressure [15]. These studies did not investigate specific ventilatory interventions aimed at decreasing DP. This study was a randomized, two parallel arm, open study whose primary outcome was to compare the effects on driving pressure of adding a RM to low-VT ventilation, with or without an individualized post-RM PEEP in patients without known previous lung disease during anesthesia

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