120 day care knee arthroplasty patients being administered nitrous oxide-isoflurane-remifentanil anesthetic were randomized to receive one of two substances. Patients either received normal saline, or 1 mg/kg iv of hydrocortisone, or 2 mg/kg iv of hydrocortisone 10 minutes before the end of anesthesia, to determine whether hydrocortisone would prevent postoperative shivering. Following assessments over an hour following administration, the results displayed that 1 mg/kg and 2 mg/kg iv doses of hydrocortisone effectively reduced postoperative shivering by similar amounts in day care knee arthroplasty patients.