Figure 5
Meta-analysis of the effect of prone positioning on 90-day mortality in acute respiratory distress syndrome patients related to positive end-expiratory pressure. The evidence we gathered shows obvious heterogeneity based on the results of the Mantel–Haenszel (M-H) χ2 test (P = 0.001) and the I2 test (I2 = 81%). A random-effects model was used. The z-test result for overall effects was statistically significant (P = 0.33) in the subgroup of patients with positive end-expiratory pressure (PEEP) levels ≥10 cmH2O. In the PEEP <10 cmH2O subgroup, the z-test result for overall effects was not statistically significant (P = 0.53). In the subgroup of patients with PEEP levels between 10 and 13 cmH2O, the z-test result for overall effects was statistically significant (P < 0.0001). “Weight” is the contribution of each study to the overall risk ratio. CI, Confidence interval; I2, Percentage of total variation across studies from between-study heterogeneity rather than chance; PP, Prone positioning; SP, Supine positioning.