Effects and safety of neostigmine for postoperative recovery of gastrointestinal function: a systematic review and meta-analysis

Background: The purpose of this study was to evaluate the clinical effects and safety of neostigmine for the postoperative recovery of gastrointestinal function. Methods: We performed a literature search of multiple databases [PubMed, Web of Science, Cochrane Library and China National Knowledge Internet (CNKI)] to retrieve studies comparing the postoperative gastrointestinal function of neostigmine and control groups. Review Manager 5.2 was applied for the analysis of heterogeneity, sensitivity, and bias. Results: After screening the articles, 17 trials involving 1,589 postoperative patients that met the eligibility criteria were included. The results suggested that neostigmine improved the first passage of flatus [standard mean difference (SMD) =-3.00; 95% confidence interval ( CI): (-4.03, -1.97); P<0.001), first defecation [SMD =-3.75; 95% CI: (-5.25, -2.24); P<0.001], time of bowel sound recovery [SMD =-3.42; 95% CI: (-4.49, -2.36), P<0.001], and gastrointestinal function recovery [risk ratio (RR) =1.84; 95% CI: (1.19, 2.86); P=0.007]. Compared to the control group, the neostigmine group had lower rates of abdominal distention [RR =0.39; 95% CI: (0.18, 0.87); P=0.02; I-2=76%] and overall adverse events [RR =0.49; 95% CI: (0.29, 0.82); P=0.007]. However, two groups had no difference in postoperative nausea and vomiting (PONV) [RR =0.50; 95% CI: (0.21, 1.23); P=0.13], and respiratory complications [RR =0.96; 95% CI: (0.20, 4.53); P=0.96]. Sensitivity and publication bias analyses showed that these results were robust and exhibited little publication bias. Discussion: Small doses of neostigmine may promote the recovery of postoperative gastrointestinal function without obvious side effects.