Preoperative dexamethasone administration in reducing the incidence of nausea and vomiting after thyroidectomy: a systematic review and meta-analysis of drug dosage

Background: Postoperative nausea and vomiting (PONV) are key contributors to the delay of recovery and cause patients' considerable discomfort. This study aimed to evaluate the influence of a specific dexamethasone dosage on PONV incidence, with a secondary objective of assessing its impact on postoperative pain in patients undergoing thyroid surgery. Methods: A meta-analysis was performed to examine the effects of preoperatively administering various doses of dexamethasone in combination with saline on PONV and pain relief in patients undergoing thyroidectomy. Relevant trials published before December 30, 2022, were searched in the PubMed, Embase, Cochrane Library, and Web of Science databases. The collected data were analyzed using RevMan 5.3 software (Cochrane), and a random-effects model or fixed-effects model was employed to conduct the meta-analysis. Results: Our meta-analysis included 11 randomized controlled trials (RCTs) with a total of 1,544 participants. The results suggested that administering dexamethasone at a dosage of 8-10 mg can reduce the incidence of PONV in patients after thyroid surgery [odds ratio (OR) 0.27; 95% CI: 0.15-0.50; I-2=82%; P<0.0001]. Additionally, administering dexamethasone at a dosage of 8-10 mg was found to be significantly more effective in reducing the incidence of PONV than was a dosage of 4-5 mg (OR 0.39; 95% CI: 0.19-0.80; I-2=29%; P=0.01). The study also revealed that administering dexamethasone at a dosage of 8-10 mg can significantly reduce pain in patients undergoing thyroidectomy [mean difference (MD): -1.19; 95% CI: -1.97 to -0.41; I-2=96%; P=0.003]. However, administering dexamethasone at a dosage of 4-5 mg did not significantly reduce pain (MD: -0.27; 95% CI: -1.00 to 0.45; I-2=0%; P=0.46) according to the subgroup analysis. Our study found that the intervention of administering dexamethasone did not have a significant impact on the consumption of analgesic drugs (MD: -0.19; 95% CI: -0.45 to 0.08; I-2=62%; P=0.16). Conclusions: A preoperative single dose of 8-10 mg of dexamethasone can significantly reduce PONV and the requirement for additional antiemetic medications, as well as alleviate postoperative pain after thyroidectomy. However, more RCTs should be conducted to determine the effects of varied dexamethasone dosages, particularly 4-5 mg, on the incidence of PONV and pain.