Fig. 4.

Forest plot. Forest plot. Mean difference of PaCO₂ with adjustments in trunk inclination from supine-flat to semi-recumbent position. TE (Treatment Effect) represents the difference in mean PaCO₂ between the two positions. SE (Standard Error): Uncertainty associated with the estimation of treatment effects. Weights: Weight (common/random): The weight that each study contributes to the calculation of the overall effect under the fixed effects model (common) and the random effects model (random). Confidence Intervals (CI): IV, Fixed + Random; 95% CI, 95% confidence interval for the difference in mean PaCO₂ in both models. Tau², Chi², and I² indicate the degree of heterogeneity among studies. Here, I² = 37% indicates moderate heterogeneity. Tests for Overall Effect: Common Effect: Z = 4.69 (p < 0.01), indicating a significant combined effect under the fixed-effects model. Random Effects: t = 3.49 (p < 0.01), indicating a significant effect under the random-effects model