Benefits of lung-protective ventilation: looking beyond the ICU.

Abstract

Background Lung-protective ventilation with the use of low tidal volumes and positive end-expiratory pressure is considered best practice in the care of many critically ill patients. However, its role in anesthetized patients undergoing major surgery is not known. Methods Objective: The aim of the study was to determine whether lung-protective ventilation improves outcomes in anesthetized patients undergoing major abdominal surgery. Design: The Intraoperative Protective Ventilation (IMPROVE) trial is a multicenter, open-label double-blind, parallel-group randomized control trial in seven French university hospitals. Setting: The IMPROVE study enrolled 400 adults at intermediate to high risk of pulmonary complications undergoing major abdominal surgeries between 31 January 2011 and 10 August 2012. Intervention: Patients were randomly assigned to receive volume-controlled ventilation in one of two strategies: nonprotective ventilation with a tidal volume of 10 to 12 ml/kg predicted body weight with no positive end-expiratory pressure and no scheduled recruitment maneuver, or lung-protective ventilation with a tidal volume of 6 to 8 ml/kg predicted body weight, a positive end-expiratory pressure of 6 to 8 cmH2O, and recruitment maneuvers every 30 minutes after intubation. Recruitment maneuvers were also standardized and applied as continuous positive airway pressure of 30 cmH2O for 30 seconds. Outcomes: The primary outcome was a composite of major pulmonary and extrapulmonary complications within the first 7 days after surgery. Major pulmonary complications were defined as pneumonia or the need for invasive or noninvasive ventilation for acute respiratory failure. Major extrapulmonary complications were defined as sepsis, severe sepsis, septic shock, and death. Secondary outcomes included components of primary outcome, surgical complications, and healthcare utilization endpoints such as the duration of stay in the ICU and hospital at the end of a 30-day follow-up period. Results The two intervention groups had similar characteristics at baseline. In the intention-to-treat analysis, the primary outcome occurred in 21 of 200 patients (10.5%) assigned to lung-protective ventilation, as compared with 55 of 200 patients (27.5%) assigned to nonprotective ventilation (relative risk, 0.40; 95% confidence interval, 0.24 to 0.68; P = 0.001). Over the 7-day postoperative period, 10 patients (5.0%) assigned to lung-protective ventilation required noninvasive ventilation or intubation for acute respiratory failure, as compared with 34 patients (17.0%) assigned to nonprotective ventilation (relative risk, 0.29; 95% confidence interval, 0.14 to 0.61; P = 0.001). The length of the hospital stay was shorter among patients receiving lung-protective ventilation than among those receiving nonprotective ventilation (mean difference, −2.45 days; 95% confidence interval, 4.17 to −0.72; P = 0.006). Conclusions As compared with a practice of nonprotective mechanical ventilation, the use of a lung-protective ventilation strategy in intermediate-risk and high-risk patients undergoing major abdominal surgery was associated with improved clinical outcomes and reduced healthcare utilization.