ObjectiveTo analyze the effects of time-worn ritual endotracheal suction (TRES) and on-demand invasive airway suction (OIAS) for patients.MethodsPubMed, EMBASE, Cochrane Library, Web of Science, EBSCO, CBM, CNKI, WanFang and VIP databases were searched for all randomized controlled trials (RCTs) comparing TRES with OIAS for patients. The studies were selected according to inclusion and exclusion criteria. The articles were assessed and data were extracted from them. The RevMan 5.3 software was used to analyze the data.ResultsSeventeen randomized controlled trials were included finally, and 2 029 patients were included, involving 1 028 patients in the control group and 1 001 patients in the experimental group. The results of meta-analysis showed that compared with TRES, OIAS could reduce the damage to the airway mucosa injury (RR=0.18, 95%CI 0.13 - 0.26, P<0.000 01), reduce secondary respiratory infections (RR=0.44, 95%CI 0.30 - 0.65, P<0.000 1), decrease the occurrence of phlegm blockade (RR=0.20, 95%CI 0.13 - 0.33, P<0.000 01), shorten the hospital stay (MD=5.03, 5%CI 3.17 - 6.89, P<0.000 01), but not influence the drop in oxygen saturation and the drop in blood oxygen pressure (RR=0.50, 95%CI 0.21 - 1.17, P=0.11). However there was no significant difference in mortality between two groups (P=0.46).ConclusionOIAS is preferred for patients who need suction than TRES.