Analgesic Efficacy of Perioperative Esmolol as an Adjunct to Morphine in Mastectomy- A Prospective Observational Study

Abstract

Introduction: Multimodal analgesia with opioids as the prime component is the mainstay of postoperative analgesia for mastectomy, which can lead to many opioid related unwanted side-effects. Esmolol infusion has been found as a useful adjunct in reducing opioid requirements. Aim: To find the effect of perioperative esmolol infusion on postoperative pain and opioid requirements. Materials and Methods: This prospective observational study was done in 140 American Society of Anaesthesiologists (ASA) physical status l and ll patients, between 20-65 years of age posted for mastectomy under general anaesthesia. Esmolol group (group E) received 0.25 mg/kg of esmolol bolus ten minutes before induction followed by continuous infusion 5 μg/kg/min till end of surgery while control group (group C) received equivalent volumes of saline. Primary outcome measures were Numerical Rating Scale (NRS) for pain, total postoperative opioid consumption and time to first rescue analgesic dosage till 24 hours. Intraoperative haemodynamics and other side-effects were secondary outcomes. Descriptive statistics of numerical rating scores and analgesic requirements were analysed in terms of mean and standard deviation. Independent t-test was used to compare numerical rating scores and analgesic requirement of the two groups. A p-value of <0.05 was considered statistically significant. Results: The mean numerical pain scores were significantly lower in the esmolol group for the first 24 hour. The mean time to first rescue analgesic was 17.59±5.012 hour in the esmolol group and 8.21±2.22 hour in the control group which was statistically significant (p<0.001). The total tramadol consumption was also significantly lesser in the esmolol group (42.14±29.03 mg), compared to control group (102.86±22.3 mg), (p=0.0001). Mean heart rate was statistically lower in the esmolol group, but there was no incidence of bradycardia requiring treatment. Mean Arterial Pressures (MAP) were comparable. Conclusion: Perioperative esmolol infusion when used as an adjunct to morphine decreased postoperative pain and analgesic requirements for the first 24 hours without any haemodynamic disturbances.