Effect of Single Compared to Repeated Doses of Intravenous S(+) Ketamine on the Release of Pro-inflammatory Cytokines in Patients Undergoing Radical Prostatectomy

BACKGROUND: Radical prostatectomy is a major surgical procedure that is associated with marked inflammatory response and impairment of the immune system which may affect the postoperative outcome. The aim of this study was to evaluate the effect of preincision single or multiple doses of S(+) ketamine on the pro-inflammatory cytokines, namely tumor necrosis factor-alpha (TNF-α) and interleukin-6 (IL-6). PATIENTS AND METHODS: This is a randomized controlled trial including 60 American Society of Anesthesiologists Physical Status I and II patients scheduled for radical prostatectomy under combined general-epidural anesthesia in Cairo university Teaching Hospital. Patients were randomly divided into three groups each of twenty patients: Group I received no S(+) ketamine (control group), Group II received S(+) ketamine as a single preincision dose, and Group III received preincision and repeated doses of S(+) ketamine. S(+) ketamine was injected as a single intravenous dose of 0.5 mg/kg in Group II and III, repeated as 0.2 mg/kg at 20 min interval until 30 min before the end of surgery. RESULTS: The three groups were comparable in age, weight, and duration of the operation. The study also revealed that a single preincision dose of S(+) ketamine decreased TNF-α to reach 1027.04 ± 50.13 μ/ml and IL-6 to reach 506.89 ± 25.35 pg/ml whereas the repeated doses of S(+) ketamine decreased TNF-α to reach 905.64 ± 35065 μ/ml and IL-6 to reach 412.79 ± 16.5 pg/ml (P < 0.05). CONCLUSION: S(+) ketamine suppresses pro-inflammatory cytokine production, especially when given in repeated doses.