Effect of esmolol infusion on myocardial oxygen consumption during extubation and quality of recovery in elderly patients undergoing general anesthesia: randomized, double blinded, clinical trial

Background: Upon recovery from anesthesia and during extubation, there will be mechanical stimulation of receptors in the respiratory tract that results in both respiratory and cardiovascular reflex responses. Heart rate plays a major determinant of myocardial oxygen consumption and cardiac workload, so decreasing the heart rate will increase the ischemic threshold and improve the cardiac performance. Objective: To evaluate the effect of esmolol infusion on myocardial oxygen consumption during extubation and quality of recovery in elderly patients undergoing general anesthesia. Methods: Hundred adult patients ASA I & II scheduled for elective open unilateral inguinal hernia were randomized, double-blindly into one of two parallel groups, esmolol group (E) (n = 50) and control group (C) (n = 50). In the esmolol group, 1 mg/kg esmolol was given as bolus over 30 s then followed by a continuous esmolol infusion of 100 μg/kg/min starting 10 min before end of surgery till 5 min after extubation. While patients in group C received normal saline bolus of the same volume followed by a continuous normal saline infusion of the same volume per hour as group E. Mean heart rate (HR), systolic blood pressure (SBP), diastolic blood pressure (DBP), mean blood pressure (MBP), rate pressure product (RPP), anesthesia time, recovery time, postoperative nausea & vomiting, number of doses of antiemetic agent and quality of extubation were recorded. Results: The results showed that patients in the esmolol group had lower values of (RPP) after esmolol infusion with statistically significant difference when compared with patients in the control group using unpaired t-test (P < 0.05), this will decrease oxygen consumption in esmolol group. Also, there was statistically significant difference between both groups regarding values of HR (beat/min), SBP (mmHg), DBP (mmHg) and MBP (mmHg) starting 2 min after esmolol infusion and continued till 10 min after extubation using unpaired t-test (p < 0.05). As regards PONV, there was lower incidence in esmolol group when compared to control group using unpaired t-test with statistically significant difference (P < 0.05). Conclusions: Esmolol is a safe, effective and well-tolerated drug that can be used in elderly patients undergoing general anesthesia to reduce the myocardial oxygen consumption and improve the quality of recovery