A Randomized, Double-Blind, Placebo-Controlled Study Assessing the Anti-inflammatory Effects of Ketamine in Cardiac Surgical Patients

Objective: To determine whether ketamine administration affects markers of inflammation in cardiac surgery with cardiopulmonary bypass (CPB) and to investigate differences between 2 low-dose ketamine regimens. Design: Prospective, randomized, placebo-controlled trial. Setting: Single-center university hospital. Participants: Patients undergoing cardiac surgery with CPB. Intervention: Patients (n = 50) were randomized to 1 of 3 groups: ketamine, 0.25 mg/kg (n = 15); ketamine, 0.5 mg/kg (n = 18);or placebo (n = 17) in a double-blind manner at the time of induction of general anesthesia. Measurements and Main Results: Serum C-reactive protein (CRP) and interleukin (IL)-6, IL-8, and IL-10 were measured at baseline, on intensive care unit (ICU) arrival, and on the first postoperative day (POD 1). Both ketamine doses decreased the serum IL-6 response at ICU arrival and POD 1 compared with placebo (p < 0.05). CRP was lower in the 0.5-mg/kg group than placebo on POD 1 (p = 0.003). IL-10 was lower in the ketamine groups (p = 0.01) at POD 1 compared with placebo; IL-8 levels were not affected by ketamine. Mean arterial pressure and systemic vascular resistance were higher at the end of surgery, arrival in the ICU, and POD 1 in the ketamine groups (p < 0.05). Conclusion: Low-dose ketamine (0.5 mg/kg) attenuates increases in CRP, IL-6, and IL-10 while decreasing vasodilatation after CPB.