Comparison of Low Dose Intravenous Fentanyl and Morphine Infusion for Postoperative Analgesia in SpineFusionSurgeries – A Randomised Control Trial

Published: 19-02-2020| Version 1 | DOI: 10.17632/msw2rg4xgb.1
Pushpa Rani


The primary objective of this study was to study the effectiveness of analgesia of low dose morphine and fentanyl infusion for postoperative analgesia following spine fusion surgeries. The secondary objectives were to assess visual analogue score (VAS), sedation score and complications like nausea, vomiting, pruritus, and respiratory depression,.After approval by the institutional ethical committee, this prospective, randomized, double-blinded study was done on100 adult patients undergoing lumbar spine fusion surgeries.The patients were randomly divided in to group M (Morphine) or group F (Fentanyl) infusion by computer generated random numbers method. The print out was taken and kept in a sealed envelope. The general anaesthesia was standardized in both the groups. The envelope was opened at this stage and first anesthesiologist prepared the solution according to the group involved. Morphine was prepared as 1mg/ml and fentanyl as 15 mcg/ml solution in an identical looking 50ml syringes.The amount of infusion and bolus dose for breakthrough pain was decided by the first anaesthesiologist based on body weight and he takes no further part in the study. The second anesthesiologist, who was blinded to the group involved, administered the solution as per dose suggested by first anesthesiologist and did monitoring and further management of the patient.Group M patients received Morphine in a dose of 0.02 mg/kg/h continuous infusion with a bolus of 0.04 mg/kg bolus for breakthrough pain. Group F patients received Fentanyl in a dose of 0.3 mcg/kg/h continuous infusion with a bolus of 0.6 mcg/kg bolus for breakthrough pain. If the patient has pain after 15 minutes, bolus dose was repeated. The total number of additional bolus doses utilized was noted. If the pain was persistent for more than 30 minutes then the study was stopped and pain was treated with morphine in titrated doses. Both the groups received infusion for first 24 hours postoperatively. The patients were followed up for further 24 hours to observe for complications. VAS was explained to the patient and was used to assess the pain. [8] The patients were given additional bolus dose when VAS > 3. The sedation was assessed using the Ramsay sedation score (RSS) .The patients were monitored continuously for vital parameters like heart rate, non-invasive blood pressure and oxygen saturation (SPO2) and values are recorded every four hours for 24 hours. The patients were observed for adverse effects like nausea, vomiting, pruritus and respiratory depression. The continuous data were expressed as mean and standard deviation and qualitative data were expressed as numberof events (%). The Student’s t test was used to compare quantitative variables. Categorical data was compared using chi-squared test or Fisher’s exact test, when appropriate. A p-value of < 0.05 was considered statistically significant.