Fig. 4
Forest plot showing the difference in cognitive function between the groups on postoperative day 1. (a) (b) denote different datasets within the same study, whereas (1) (2) denote different studies. The diamond (â—†) represents the overall pooled effect estimate, while the squares (â– ) indicate the weight of individual studies, with the size of each square proportional to the study's contribution to the meta-analysis. CI, confidence interval; Std., standardized; IV: invariance