Figure 6
Meta-analysis of the effect of prone positioning on 28- to 30-day mortality in acute respiratory distress syndrome patients related to the duration of prone positioning. The evidence we gathered shows obvious heterogeneity based on the results of the Mantel–Haenszel (M-H) χ2 test (P = 0.01) and the I2 test (I2 = 64%). A random-effects model was used. The z-test result for overall effects was not statistically significant (P = 0.15). In the subgroup of patients with prone positioning (PP) duration ≥12 h/day, the z-test result for overall effects was statistically significant (P = 0.04). In the subgroup of patients with PP duration <12 h/day, the z-test result for overall effects was statistically significant (P = 0.60). “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; SP, Supine positioning.