Gum Chewing and Coffee Consumption but not Caffeine Intake Improve Bowel Function after Gastrointestinal Surgery: a Systematic Review and Network Meta-analysis

BACKGROUND: Postoperative ileus is common after gastrointestinal surgery. This network meta-analysis aimed to compare the effectiveness of gum chewing and coffee and caffeine intake on ileus-related outcomes. METHODS: A systematic literature review was performed to identify randomized controlled trials (RCTs) comparing noninvasive treatments for ileus after gastrointestinal surgery. The main analyses included random effects network meta-analyses using frequentist methods with simultaneous direct and indirect comparisons of time to first flatus, time to first defecation, and length of stay. Bayesian network meta-analysis using Markov chains was also used. RESULTS: A total of 32 RCTs comparing 4999 patients were included in this network meta-analysis. Time to flatus was reduced by gum chewing (mean difference compared to control (MD): -11 h, 95% confidence interval (95% CI) − 16 to − 5 h, P < 0.001). Time to defecation was reduced by gum chewing and coffee, with MDs of -18 h (95% CI − 23 to − 13 h, P < 0.001) and -13 h (95% CI − 24 to − 1 h, P < 0.001), respectively. Length of stay was reduced by coffee and gum chewing with MDs of − 1.5 days (95% CI: − 2.5 to − 0.6 days, P < 0.001) and − 0.9 days (95% CI: − 1.3 to − 0.4 days, P < 0.001), respectively. CONCLUSION: Coffee and gum chewing were proven to be effective noninvasive approaches for shortening the postoperative length of hospital stay and time to first defecation, especially in open gastrointestinal surgery; thus these actions should be recommended after gastrointestinal surgery. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s11605-023-05702-z.