Fig. 4

a Forest plot of 24-h postoperative oral morphine (mg) equivalent consumption. The MD estimates for each study are represented by squares and the lines passing through them represent 95% CI. The diamond represents the overall pooled estimate. b 24-h postoperative oral morphine (mg) equivalent consumption (forest plot for subgroup analysis). MD Mean difference, CI Confidence interval, IV Inverse variance, SD Standard deviation, ESPB Erector spinae plane block, SAPB Serratus anterior plane block, VATS Video-assisted thoracoscopic surgery