Table of Contents

Study Protocol

Here you will find a short summary of the PROBESE trial. For further details, please use the navigator on the left side.

Summary

Rationale

Postoperative respiratory failure, particularly after surgery under general anesthesia, adds to the morbidity and mortality of surgical patients. Anesthesiologists inconsistently use positive end–expiratory pressure (PEEP) and recruitment maneuvers in the hope that this may improve oxygenation and protect against postoperative pulmonary complications (PPCs), especially in obese patients. While anesthesiologists tend to use PEEP higher than in non-obese patients. While it is uncertain whether a strategy that uses higher levels of PEEP with recruitment maneuvers truly prevents PPCs in these patients, use of higher levels of PEEP with recruitment maneuvers could compromise intra–operative hemodynamics.

Objectives

To compare a ventilation strategy using higher levels of PEEP with recruitment maneuvers with one using lower levels of PEEP without recruitment maneuvers in obese patients at an intermediate–to–high risk for PPCs.

Hypotheses

An intra–operative ventilation strategy using higher levels of PEEP and recruitment maneuvers, as compared to ventilation with lower levels of PEEP without recruitment maneuvers, prevents PPCs in obese patients at an intermediate–to–high risk for PPC.

Study design

International multicenter randomized controlled trial.

Study population

Obese patients with BMI ≥ 35 kg/m2 at intermediate–to–high risk for PPCs scheduled for surgery under general anesthesia.

Main study parameters/endpoints

The primary endpoint is the proportion of patients with PPCs. Secondary endpoints include intra–operative complications, need for postoperative ventilatory support (invasive and/or non–invasive ventilation), need for unexpected ICU admission or ICU readmission, the number of hospital–free days and 90-day survival/mortality.

Nature and extent of the burden and risks associated with participation, benefit and group relatedness

In the intra–operative period, patients will not experience discomfort from either strategy because of general anesthesia. However, systemic hypotension could occur in the higher PEEP group, which would be treated with intravascular volume therapy and/or vasoactive drugs. If the hypothesis proves to be true, patients in the higher PEEP group could benefit from a lower incidence of PPCs. Blood samples will be collected via an existing intravenous catheter or via direct vein puncture, but always in combination with blood sampling for routine care; the amount of additional blood samples can be considered minimal.