Effect of dexamethasone on intraoperative remifentanil dose in total knee arthroplasty surgery under general anaesthesia

Background: The effects of glucocorticoids may include both genomic and rapid nongenomic effects. The potential rapid analgesic effect during surgery has not previously been investigated. We aimed to explore the effect of dexamethasone on intraoperative infusion rate of remifentanil in patients undergoing total knee arthroplasty (TKA) surgery under general anaesthesia. Methods: In this post hoc subgroup analysis, we included patients randomised in the DEX-2-TKA trial, who were operated under total intravenous anaesthesia with remifentanil and propofol. Trial medication, intravenous dexamethasone 24 mg or placebo, was administered immediately after anaesthesia onset. The primary outcome was the median weight-corrected infusion rate of remifentanil during surgery. Secondary outcomes included median weight-corrected infusion rate of propofol, median intraoperative bispectral index and time spent in the post-anaesthesia care unit. Results: Eighty-seven patients were included in the analysis of the primary outcome. A significantly higher remifentanil infusion rate was observed in the dexamethasone group compared with the placebo group, p =.02. None of the secondary outcomes resulted in statistically significant differences between groups. Conclusion: This explorative post hoc analysis of the randomised DEX-2-TKA trail showed that patients undergoing TKA surgery under general anaesthesia and who received dexamethasone seemed to have a higher remifentanil infusion rate compared with patients who received placebo. The clinical implications of the potentially increased remifentanil infusion rate need to be validated and explored further. Clinical trial registration: ClinicalTrials.gov Identifier: NCT05002361 (12 August 2021).