Effect of adding tetracaine to bupivacaine on duration of analgesia in supraclavicular brachial plexus nerve blocks for ambulatory shoulder surgery.

The objective of this study was to determine if the addition of 1% tetracaine to 0.25% bupivacaine prolonged the duration of postoperative analgesia of supraclavicular brachial plexus nerve blockade for patients undergoing ambulatory shoulder surgery. We conducted a prospective, double-blinded, randomized controlled clinical study at an ambulatory surgery center utilizing ultrasound- and nerve stimulation-guided supraclavicular nerve blockade for postoperative analgesia. The control group received 30 mL of 0.25% bupivacaine plus 4 mL preservative-free saline. The study group received 30 mL of 0.25% bupivacaine plus 4 mL of 1% tetracaine. Patients documented their visual analog scale scores and intake of pain medications for 3 days. Primary outcomes included time of first postoperative pain, time of first postoperative pain pill, and time of return of motor and sensory function. Secondary outcomes included pain score and pain medication intake trends and adverse events secondary to the nerve block. A total of 84 patients completed the study, 42 patients in each group. The study group was statistically significantly older than the control group (mean age, 54 vs 48 years; P = 0.04). The mean duration of analgesia was 16.6 ± 8.3 h for the control group and 17.1 ± 7.3 h for the study group (P = 0.69). No outcomes were statistically different. In conclusion, there was no significant difference in duration of postoperative analgesia with the addition of 1% tetracaine to 0.25% bupivacaine in supraclavicular brachial plexus nerve blockade. No differences were identified in postoperative pain medications, pain scores, or complications.