Risk of Postoperative Nausea and Vomiting After Total Hip or Knee Arthroplasty Under Spinal Anesthesia

Background: Acupoint stimulation has been shown to reduce the risk of postoperative nausea and vomiting (PONV) after various types of surgeries involving general anesthesia, but whether the same is true after orthopaedic surgery involving spinal anesthesia is unclear. The purpose of this study was to compare PONV rates and the quality of recovery between patients undergoing total hip arthroplasty (THA) or total knee arthroplasty (TKA) under spinal anesthesia receiving conventional antiemetics alone and those receiving antiemetics combined with use of a transcutaneous electrical acupoint stimulation bracelet (EmeTerm; WAT Medical Enterprise). Methods: Patients at moderate or high risk for PONV, including 195 patients undergoing THA and 153 patients undergoing TKA, were randomized to receive routine antiemetics (dexamethasone and ondansetron) alone or with use of the EmeTerm bracelet. The primary outcome was the PONV incidence within 24 hours postoperatively; secondary outcomes included the rates of severe PONV, antiemetic rescue, adverse events, and Quality of Recovery scores. Results: Combining antiemetics with the EmeTerm bracelet significantly reduced PONV (16.0% compared with 31.2%; p = 0.001), severe PONV (1.1% compared with 8.1%; p = 0.002), and antiemetic rescue (3.4% compared with 13.9%; p = 0.001). Use of the bracelet reduced the risk of PONV within 24 hours by 61% (adjusted hazard ratio, 0.39; 95% confidence interval [CI], 0.24 to 0.63), and its benefit became significant at 0 to 3 and 3 to 6-hour intervals after surgery. The complete response rate was higher for the bracelet + antiemetics group compared with the group with antiemetics alone (84.0% compared with 68.8%; p = 0.001), with better Quality of Recovery scores at 24 hours in the bracelet + antiemetics group. Conclusions: The EmeTerm bracelet enhanced the efficacy of antiemetics in reducing PONV after THA and TKA under spinal anesthesia and may improve short-term recovery. Level of Evidence: Therapeutic Level I . See Instructions for Authors for a complete description of levels of evidence.