Study Summary

Seventy-eight patients with distal lower extremity surgical conditions requiring a thigh tourniquet were randomized to receive an esketamine infusion or a saline placebo (0.9%). The primary outcome of interest was the incidence of tourniquet-induced hypertension, defined as a systolic blood pressure increase >30% above the pre-tourniquet level. Secondary outcomes included intra-operative hypotension, haemodynamic variables, esmolol consumption, postoperative pain scores, tramadol use, nausea and vomiting, psychological adverse effects, quality of recovery at 24 hours, and duration of hospital stay. Outcomes were assessed intra-operatively and up to 48 hours postoperatively. Overall, the results of the study revealed that esketamine significantly reduced the incidence of tourniquet-induced hypertension compared with placebo without increasing adverse effects. These findings suggest esketamine infusion may improve haemodynamic stability during below-knee orthopaedic surgery.