Methods: After approval from the hospital ethics committee was obtained, we analyzed 64 ASA II patients who were scheduled for coronary artery bypass graft surgery. In the double-blind study, patients were divided into two subgroups before anesthesia induction with fentanyl-midazolam-rocuronium and randomized to esmolol (group E; n=32) or saline (group S; n=32). Following baseline measurements of vital signs and BIS score, patients received either 1 mg/kg esmolol intravenous or the equivalent volume of saline five minutes before anesthesia induction. Heart rate, mean arterial pressure and the BIS responses were recorded at baseline, at two minutes following infusion, at five minutes following induction, and at one, two and three minutes following intubation. The primary outcome of the study was Δ BIS. The study achieved a power of 95% for a-20%-change in Δ BIS.

Results: In the esmolol group, heart rate was decreased significantly compared to baseline in the second time point. Mean arterial pressure was similar between the groups at any time point. The BIS response was significantly higher in the saline group at one and two minutes following intubation, compared to esmolol group.

Conclusion: This study demonstrated that esmolol did not only decrease the heart rate within two minutes after injection but also attenuated BIS increases after the stimulation of orotracheal intubation. In addition, it seems that esmolol deepened the fentanyl-midazolam anesthesia.