Role of tramadol as an adjuvant in ultrasound-guided serratus anterior muscle block for modified radical mastectomy - A randomized control trial

Modified radical mastectomy (MRM) is associated with significant acute post-operative pain that may progress to chronic pain syndromes in 25–60% of patients. Serratus anterior muscle (SAM) block has proved to be an excellent analgesic option in patients undergoing MRM. Although many adjuvants have been utilized for the prolongation of analgesia, the role of tramadol in SAM has not been studied as yet. We hypothesize that the addition of tramadol to ropivacaine for SAM block may reduce morphine consumption in the post-operative period in patients undergoing elective MRM surgeries. The primary aim of the study was to compare cumulative post-operative morphine consumption over 24 h in patients receiving SAM block with or without tramadol. The secondary aims were to observe adverse events related to the procedure or medications. The other parameters recorded were non-invasive blood pressure (NIBP), pulse rate, respiratory rate, and nausea or vomiting. Patients scheduled to undergo MRM were randomly allocated by block randomization into two groups. The study group (Group T) received a SAM block with 0.25% ropivacaine (18 ml) with tramadol 100 mg while the control group (Group P) received a SAM block with 18 ml of 0.25% ropivacaine and 2 ml of saline. Patients were assessed for pain scores, analgesic requirement, time to first analgesic request, hemodynamic variables, and any side-effects at 30 min, 1 h, 4 h, 8 h, 12 h, and 24 h post-operatively. Cumulative morphine consumption over 24 h in the post-operative period was less in the group T (3.06 ± 1.53 mg vs 4.34 ± 1.53 mg; P 0.001). Time to the first analgesic requirement was more in group T (10.44 ± 5.04 h vs 6.11 ± 2.73 h; P < 0.001). Pain scores were significantly lower in the group T at all time points. Tramadol, when used as an adjuvant to ropivacaine for SAM block reduces post-operative pain scores in the first 24 h and prolongs the time of first morphine requirement.