Figure 5.

(A) Forest plot for ICU stay. (B) Trial sequential analysis for ICU stay. Risk of type 1 error was maintained at 5% with a power of 90%. The variance was calculated from the data obtained from the included trials. A clinically significant anticipated mean difference of duration of ventilation was set at 1 day. The blue line is the cumulative Z curve, and each black square dot represents 1 trial. The brown horizontal lines indicate a conventional significant P value of .05. The red diagonal lines represent the futility region. The red vertical lines are the trial sequential monitoring boundaries. In total, 1098 patients were analyzed, and the Z curve did not cross the monitoring boundary. CI = confidence interval, MD = mean difference, PU = polyurethane, PVC = polyvinyl chloride, RIS = required information size, SSD = subglottic secretion drainage.