Low-dose ketamine affects immune responses in humans during the early postoperative period

Abstract

Background: Anaesthesia and surgery are associated with impairment of the immune system expressed as an excessive proinflammatory immune response and suppression of cell-mediated immunity that may affect the course of the postoperative period. Addition of anaesthetic agents capable of attenuating the alterations in perioperative immune function may exert a favourable effect on patients' healing. We have assessed the effect of preoperative administration of a sub-anaesthetic dose of ketamine on the mitogen response and production of interleukin (IL)-1beta, IL-2, IL-6, and tumour necrosis factor (TNF)-alpha by peripheral blood mononuclear cells (PBMCs), as well as natural killer cell cytotoxicity (NKCC) in patients undergoing abdominal surgery.

Methods: Seventeen patients admitted for elective abdominal surgery were given ketamine 0.15 mg kg(-1) i.v. 5 min before induction of general anaesthesia. Nineteen patients received a similar volume of isotonic saline 5 min before induction of the anaesthesia. PBMCs were isolated from venous blood before and 4, 24, 48, and 72 h after operation for IL-1beta, IL-2, IL-6, and TNF-alpha secretion, and NKCC assessment.

Results: Four hours after operation, the cells from patients in the ketamine group showed a significantly suppressed production of IL-6 (P < 0.01) compared with controls. The production of IL-2 did not change from that of the preoperation samples. TNF-alpha secretion was significantly elevated in the control group 4 h after operation (P < 0.05).

Conclusions: Addition of small doses of ketamine before induction of anaesthesia resulted in attenuation of secretion of the proinflammatory cytokines IL-6 and TNF-alpha, and in preservation of IL-2 production at its preoperative level. It is suggested that this anaesthetic may be of value in preventing immune function alterations in the early postoperative period.