High versus low positive end-expiratory pressure during general anaesthesia for open abdominal surgery (PROVHILO trial): a multicenter randomized controlled trial.
PROVE Network Investigators for the Clinical Trial Network
Summary
Background The role of positive end-expiratory pressure in mechanical ventilation during general anaesthesia for
surgery remains uncertain. Levels of pressure higher than 0 cm H2O might protect against postoperative pulmonary
complications but could also cause intraoperative circulatory depression and lung injury from overdistension.
We tested the hypothesis that a high level of positive end-expiratory pressure with recruitment manoeuvres protects
against postoperative pulmonary complications in patients at risk of complications who are receiving mechanical
ventilation with low tidal volumes during general anaesthesia for open abdominal surgery.
Methods In this randomised controlled trial at 30 centres in Europe and North and South America, we recruited
900 patients at risk for postoperative pulmonary complications who were planned for open abdominal surgery under
general anaesthesia and ventilation at tidal volumes of 8 mL/kg. We randomly allocated patients to either a high level
of positive end-expiratory pressure (12 cm H2O) with recruitment manoeuvres (higher PEEP group) or a low level of
pressure (2 cm H2O) without recruitment manoeuvres (lower PEEP group). We used a centralised computergenerated
randomisation system. Patients and outcome assessors were masked to the intervention. Primary endpoint
was a composite of postoperative pulmonary complications by postoperative day 5. Analysis was by intention-to-treat.
The study is registered at Controlled-Trials.com, number ISRCTN70332574.
Findings From February, 2011, to January, 2013, 447 patients were randomly allocated to the higher PEEP group
and 453 to the lower PEEP group. Six patients were excluded from the analysis, four because they withdrew consent
and two for violation of inclusion criteria. Median levels of positive end-expiratory pressure were 12 cm H2O
(IQR 12–12) in the higher PEEP group and 2 cm H2O (0–2) in the lower PEEP group. Postoperative pulmonary
complications were reported in 174 (40%) of 445 patients in the higher PEEP group versus 172 (39%) of 449 patients
in the lower PEEP group (relative risk 1·01; 95% CI 0·86–1·20; p=0·86). Compared with patients in the lower PEEP
group, those in the higher PEEP group developed intraoperative hypotension and needed more vasoactive drugs.
Interpretation A strategy with a high level of positive end-expiratory pressure and recruitment manoeuvres during
open abdominal surgery does not protect against postoperative pulmonary complications. An intraoperative protective
ventilation strategy should include a low tidal volume and low positive end-expiratory pressure, without recruitment
manoeuvres