Influence of esmolol on requirement of inhalational agent using entropy and assessment of its effect on immediate postoperative pain score

BACKGROUND AND CONTEXT: Beta-blockers have been used for attenuation of stress response, decreasing anaesthetic requirement and augmentation of the effect of opioids during general anaesthesia. AIMS AND OBJECTIVES: The present study aims to evaluate the influence of esmolol on the requirement of an inhalational agent while monitoring the depth of anaesthesia by entropy and also its effect on immediate postoperative pain score. METHODS: Fifty American Society of Anaesthesiologists (ASA) I and II patients, between 25 and 65 years of age who underwent lower abdominal surgeries were randomly allocated to two groups: Group E and Group S of 25 patients each. Group E received esmolol infusion while Group S received the same volume of saline infusion. Demographic data, haemodynamics, amount of isoflurane used, end-tidal isoflurane concentration, postoperative pain score and total dose of morphine consumed in immediate postoperative period of 30 min were analyzed by using appropriate statistical tests. Value of P<0.05 was considered significant and P<0.001 as highly significant. RESULTS: The two groups were comparable with respect to age, weight, ASA physical status, duration of surgery and amount of isoflurane used during anaesthesia. Assessment of postoperative pain was assessed by Visual Analogue Scale (VAS) which showed significant difference at 30 min. The total dose of morphine consumption was significantly less (P<0.05) in Group E for relief of postoperative pain. CONCLUSIONS: We conclude that in light of depth of anaesthesia monitor esmolol has no effect on requirement of isoflurane, but it decreases the postoperative pain as well as postoperative requirement of morphine without increasing the risk of awareness.