Nitrous Oxide to Reduce Wound Care-Related Pain in Adults: A Systematic Review and Meta-Analysis

Significance: As an essential procedure, wound care comes with acute pain, which is short but high in intensity, causing patients to fear and affecting subsequent treatment. Nitrous oxide (N₂O) is used to relieve pain related to wound care; however, evidence regarding its application is conflicting. Thus, this systematic review and meta-analysis was performed to evaluate the efficacy of N₂O in wound care-related pain. Recent Advances: Randomized controlled trials that investigated the effect of N₂O in adults undergoing wound care were systematically searched from PubMed, Embase, the Cochrane Library, Web of Science, Scopus, and ClinicalTrials.gov up to February 2023. The primary outcome was the pain score. Secondary outcomes included patients' satisfaction and side effects. Critical Issues: Through screening the 265 identified articles, seven and six studies were finally included in the systematic review and meta-analysis, respectively. Pooled analysis suggested that there was no significant difference in reducing wound care-related pain between the N₂O group and the control group (mean difference [MD], -0.02, 95% confidence interval [CI], -1.46, 1.42; p = 0.98, I² = 96%). Subgroup analyses indicated that there was a significant difference in favor of N₂O for burns, not for ulcers, and N₂O was superior to oxygen and similar to topical or intravenous anesthesia. There was no significant difference in patients' satisfaction or the incidence of side effects between groups. Future Directions: This review suggests that N₂O might be effective for pain management in patients undergoing wound care. Caution must be taken when interpreting these results due to the high risk of biased methods in the included studies.