Effect of Tidal Volume on Pulmonary Outcomes After Surgery

Abstract

Role of the Funder/Sponsor: The funders had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.Disclaimer: This article does not represent the views of the Department of Veterans Affairs or the US government.

Intra-operative ventilator mechanical power as a predictor of postoperative pulmonary complications in surgical patients

“…Previous studies in critically ill patients have suggested that whilst lower inspiratory pressures are beneficial, higher respiratory rates may be harmful. 20 This led to an interest in how such opposing factors may interact. Mechanical power, a measure that aims to integrate static and dynamic parameters of ventilation, could be a more important variable in the relationship between ventilation and lung injury.…”

“…Mechanical power, a measure that aims to integrate static and dynamic parameters of ventilation, could be a more important variable in the relationship between ventilation and lung injury. 20 This is based on the rationale that VILI is not only a function of static parameters, such as strain from V T or stress from inspiratory pressures but also on the complex interplay between static and dynamic variables, including the rate of lung deformation (strain rate) and the cycling frequency, or respiratory rate. 14 20 Mechanical power has been suggested as an index of the overall energy applied to the lungs, which encompasses the impact of both driving pressure and respiratory rate.…”

“…Recently, an RCT evaluating the impact of V T on the incidence of PPCs was published and showed no impact of lower or higher V T on this outcome. 19 However, as pointed out in an accompanying letter, 20 the study failed to consider the association between mechanical power and the risk of PPCs. Accordingly, we performed a post hoc analysis of a large randomised clinical trial to assess the association of mechanical power with clinical outcomes in patients receiving mechanical ventilation during major noncardiothoracic, nonintracranial surgery.…”

Mechanical Power during General Anesthesia and Postoperative Respiratory Failure: A Multicenter Retrospective Cohort Study

“…ill patients 40 and a limited post hoc analysis of a randomized, controlled trial in the operating room. 16 The lack of effectiveness in randomized controlled trials of intraoperative mechanical ventilation interventions may be explained by the absence of a comprehensive focus on the multiple factors that contribute to ventilator-induced lung injury 9 -for example, increasing respiratory rate might offset effects of decreasing tidal volume, as observed in previous studies. 6 We found that only the dynamic elastic component was associated with greater risk of postoperative reintubation, but the static and dynamic resistive components were not.…”

“…7 While tidal volume was the only randomized variable in these studies, there was an associated increase in respiratory rate, potentially offsetting the beneficial effect of lowering tidal volume. 8,9 This illustrates the need for a unifying concept that integrates the effects of changes in multiple parameters when adjusting mechanical ventilation to reduce perioperative ventilator-induced lung injury.…”