Sensitivity Analysis
For pooled results with substantial heterogeneity, the sensitivity analysis was conducted by excluding trials for each outcome. We found the heterogeneity significantly decreased. For the outcome of the usage of rescue analgesia, there were statistically significant difference between the IVIB and placebo (RR, 0.16; 95% CI, 0.08 to 0.34, 8 trials, moderate certainty) or acetaminophen (RR, 0.26; 95% CI, 0.14 to 0.49, 5 trials, high certainty) when excluding Daniels et al (43) (300mg IVIB), which was lower than that in other studies. The results were not changed in remaining outcomes (Supplementary Table 5). The robustness of results was also carried out by removing trials of overall high risk of bias, and no material change was observed in each outcome results (Supplementary Table 6).
DISCUSSION
We found moderate-to-low certainty evidence that preoperative IVIB could reduce the pain intensity within 24 hours after various surgeries compared with placebo, regardless of single-dose or administrated every 6 hours or 8 hours. Furthermore, compared with intravenous acetaminophen, IVIB was basically associated with lower pain scores within postoperative 24h. IVIB (800 mg) could reduce morphine consumption at both 24h and 48h postoperatively, whereas IVIB (400 mg) showed no benefit. IVIB (400mg or 800mg) could reduce the need for rescue analgesics compared with placebo and intravenous acetaminophen. In another hand, IVIB appeared satisfactory antipyretic efficiency in a short period of time in adults, but there was no difference between IVIB and intravenous acetaminophen. In terms of safety, IVIB was well tolerated in both pain and fever management, and was associated with a lower incidence of nausea or vomiting compared with placebo or intravenous acetaminophen. As a result, IVIB represents an effective and well tolerated agent for the treatment of acute perioperative analgesic when oral agents may be impractical or when rapid onset with predictable therapeutic dosing is needed in hospitalized patients.