Comparative Effectiveness of Protective Ventilation Strategies for Moderate and Severe Acute Respiratory Distress Syndrome. A Network Meta-Analysis.

Abstract

<b>Rationale:</b> Choosing the best ventilation strategy for acute respiratory distress syndrome (ARDS) is complex, yet it is highly relevant to clinicians during a respiratory pandemic. <b>Objectives:</b> To compare the effects of low Vt, high Vt, high positive end-expiratory pressure (PEEP), prone ventilation, high-frequency oscillation, and venovenous extracorporeal membrane oxygenation (VV ECMO) on mortality in ARDS. <b>Methods:</b> We performed a network meta-analysis of randomized trials. We applied the Grading of Recommendations Assessment, Development and Evaluation methodology to discern the relative effect of interventions on mortality. <b>Measurements and Main Results:</b> We analyzed 34 trials including 9,085 adults with primarily moderate-to-severe ARDS (median baseline Pa_O2/Fi_O2, 118; interquartile range, 110-143). Prone positioning combined with low Vt was the best strategy (risk ratio [RR], 0.74 [95% confidence interval (CI), 0.60-0.92] vs. low Vt; high certainty). VV ECMO was also rated among the best (RR, 0.78 [95% CI, 0.58-1.05] vs. low Vt; RR, 0.66; [95% CI, 0.49-0.88] vs. high Vt) but was rated with lower certainty because VV ECMO was restricted to very severe ARDS (mean baseline Pa_O2/Fi_O2<75). High PEEP combined with low Vt was rated intermediately (RR, 0.91 [95% CI, 0.81-1.03] vs. low Vt; low certainty; RR, 0.77 [95% CI, 0.65-0.91] vs. high Vt; moderate certainty). High Vt was rated worst (RR, 1.19 [95% CI, 1.02-1.37] vs. low Vt; moderate certainty), and we found no support for high-frequency oscillation or high Vt with prone ventilation. <b>Conclusions:</b> These findings suggest that combining low Vt with prone ventilation is associated with the greatest reduction in mortality for critically ill adults with moderate-to-severe ARDS.