Efficacy of Different Doses of Dexamethasone as Pre-emptive Analgesia in Patients Undergoing Total Abdominal Hysterectomy under General Anaesthesia: A Prospective Non Randomised Placebo Controlled Study

Introduction: Pre-emptive analgesia reduces postoperative analgesic requirement, avoiding side-effects that occur with parenteral narcotics. Dexamethasone, a long acting synthetic corticosteroid with predominantly glucocorticoid activity is one of the entities used for pre-emptive analgesia. The optimum dose of dexamethasone for pre-emptive analgesia is not defined. Aim: To study the efficiency of different (low, intermediate and high) doses of dexamethasone as pre-emptive analgesia in patients undergoing total abdominal hysterectomy under general anaesthesia. Materials and Methods: The prospective non randomised placebo controlled dose range study was conducted in the Department of Anaesthesiology, at a tertiary care institute at Srinagar, Jammu and Kashmir, India, over a period of two years from July 2017 to June 2019. Eighty female patients (age 40-65 years, American Society of Anaesthesiologists (ASA) I and II) scheduled for total abdominal hysterectomy were divided into four groups (Groups A, B, C and D) on the basis of dexamethasone dose. Group A with low dose (0.1 mg/kg), group B with intermediate dose (0.12-2 mg/kg), group C with high dose (>0.2 mg /Kg) and group D with no Dexamethasone. Early and late acute postoperative pain {Visual Analog Scale (VAS) score}, cumulative analgesic consumption upto 24 hours, intraoperative blood sugar levels, Postoperative Nausea and Vomiting (PONV), and adverse events were recorded. Analysis of variance (ANOVA) was used for intergroup comparison of means and Chi-square test was used for categorical variables. Results: The mean age (years) of Group A was 52.3 +/- 8.87, Group B was 48.3 +/- 5.23, Group C was 49.8 +/- 6.85 and Group D was 51.7 +/- 4.46. Postoperative VAS score for 0 hour, 1 hour, 2 hour, 3 hour, 4 hour was more in patients who had not received dexamethasone pre-emptively (p-value<0.05). VAS score at 6 hour, 12 hour, 24 hour was more in patients who had not received dexamethasone pre-emptively. There was a statistically significant difference in VAS score at 6, 12, 24 hours when low dose dexamethasone group was compared with intermediate and high dose dexamethasone groups (p-value<0.05). Rescue analgesia consumption was significantly less in patients who received intermediate to high dose dexamethasone. Blood sugar levels increased significantly in patients receiving dexamethasone, but returned to baseline after 24 hours. The incidence of nausea and vomiting and the need for rescue antiemetic was significantly less in patients receiving dexamethasone (p-value<0.05). The incidence of postoperative adverse effects was not different among these groups (p-value>0.05). Conclusion: Intermediate and high dose dexamethasone, given preoperatively in patients undergoing abdominal hysterectomy produces better postoperative analgesia with added antiemetic benefit.