Effect of low-dose ketamine on inflammatory response in off-pump coronary artery bypass graft surgery

Background: Off-pump coronary artery bypass graft surgery (OPCAB) is stillassociated with a marked systemic inflammatory response. Theaim of this study was to investigate whether pre-emptive, lowdose of ketamine, which has been reported to have anti-inflammatoryactivity in on-pump coronary artery bypass surgery, could reduceinflammatory response in low-risk patients undergoing OPCAB. Methods: In this prospective randomized-controlled trial, 50 patientswith stable angina and preserved myocardial function undergoingOPCAB were randomly assigned to receive either 0.5 mg kg^–1of ketamine (Ketamine group, n=25) or normal saline (Controlgroup, n=25) during induction of anaesthesia. Inflammatory markersincluding C-reactive protein (CRP), interleukin (IL)-6, tumournecrosis factor- (TNF-), and cardiac enzymes were measured previousto induction (T1), 4 h after surgery (T2), and the first andsecond days after the surgery (T3 and T4). Results: There were no significant intergroup differences in the serumconcentrations of the CRP, IL-6, and TNF- and cardiac enzymes.Pro-inflammatory markers and cardiac enzymes, except TNF-, wereall increased after the surgery compared with baseline valuesin both groups. Conclusions: Low-dose ketamine administered during anaesthesia inductiondid not exert any evident anti-inflammatory effect in termsof reducing the serum concentrations of pro-inflammatory markersin low-risk patients undergoing OPCAB.