The lateral-Trendelenburg vs. semirecumbent body position for the prevention of ventilator-associated pneumonia - The Gravity-VAP Trial

Background: Pre-clinical studies confirmed benefits associated with the lateral-Trendelenburg position (LTP) vs. the semi-recumbent position (SRP) in the prevention of ventilator-associated pneumonia. Methods: We conducted a randomized, single-blind, multicenter, controlled study. Critically ill, mechanically ventilated patients were randomized to be positioned in LTP or SRP. Primary outcome was VAP incidence rate, based on quantitative bronchoalveolar lavage fluid culture ≥ 104 colony-forming units/mL. Secondary outcomes were duration of mechanical ventilation, intensive care unit (ICU) and hospital stays, and ICU/hospital/28-day mortality. Results: Three hundred ninety-five patients were randomized, 194 in LTP and 201 in SRP. The data safety monitoring board recommended stopping the study at the second interim analysis for low incidence of VAP in the control group, lack of benefits in any major secondary outcome and adverse events in the LTP group. The incidence of microbiologically confirmed VAP was 0.5% (1/194 patients) in patients positioned in LTP, and 4.0% (8/201 patients) in patients in SRP, risk ratio (RR) between groups 0.13, 95% confidence interval (CI) 0.02–1.03, p=0.04. Microbiologically confirmed VAP per 1000 ventilator days was 0.88 (95%CI 0.12-6.25) and 7.19 (95%CI 3.60-14.37) in the LTP and SRP, respectively, RR 0.12 (95%CI 0.01-0.91), p=0.02. No statistically significant between-group differences were observed in secondary outcomes. Conclusions: LTP potentially reduces risks of VAP, compared with the SRP. Yet, due to study limitations, further studies are mandatory to corroborate these findings in populations at higher risk of VAP.