Poster 163: The Effect of Subacromial Epinephrine Injection on Visualization during Shoulder Arthroscopy

OBJECTIVES: Arthroscopic technique is used to treat an increasingly wide variety of pathologic conditions of the shoulder. Adequate visual clarity is imperative for the safety and efficacy of these procedures. Addition of epinephrine to arthroscopic irrigation fluid has been shown to improve surgeon-rated visual clarity, but also increases the cost of the procedure and carries the potential for rare, but serious, cardiovascular adverse events as the total dose increases. We utilize a preoperative subacromial injection containing epinephrine to improve visual clarity during arthroscopic shoulder surgery, thereby limiting the total dose of epinephrine added to the arthroscopic fluid. METHODS: We performed a double-blinded, randomized controlled trial (institutional IRB approved and registered with clinicaltrials.gov) to include all adult patients undergoing arthroscopic shoulder surgery requiring visualization of the subacromial space in the seated upright (i.e., beach chair) position. We performed a preoperative injection into the subacromial space with bupivacaine alone for the control group versus a combination of bupivacaine and epinephrine for the study group. Epinephrine was also added to the first fifteen liters of arthroscopic fluid in all patients. Primary outcome was surgeon-rated visual clarity throughout the procedure using the visual analog score (VAS; 1 to 10). A power analysis determined the need for a minimum sample size in each group to ensure adequate power given that the minimal clinically significant difference in visual clarity score has been established in prior studies to be two points. Secondary outcomes included increase in pump pressure during the procedure to improve visualization, total operative time and intraoperative use of blood-pressure modulating medications. We documented any adverse events in the perioperative period in all patients. RESULTS: Sixty patients (n = 60) were enrolled in the study, thirty (n = 30) randomized into each of the study and control groups. Rotator cuff repair was performed in 88% of cases (25 of 30 (83%) study; 28 of 30 (93%) control) with multiple procedures performed in each surgery in 85% of cases (24 of 30 (80%) study; 27 of 30 (90%) control). There was a small improvement in visual clarity that was neither statistically nor clinically significant (8.3 ± 1.4 study versus 7.5 ± 1.9 control, p = 0.09). There was no difference in need for increase in pump pressure to improve visualization (8 of 30 patients (27%) study versus 7 of 30 patients (23%) control, p = 1.0), total operative time (62.1 ± 19.4 min study versus 64.1 ± 31.0 min control, p = 0.86), or intraoperative use of blood-pressure modulating medications (20 of 30 patients (67%) study versus 17 of 30 (57%) control, p = 0.6). There were no perioperative adverse events in either the study or control group. CONCLUSIONS: Performing a preoperative injection of epinephrine into the subacromial space results in a small improvement in visual clarity that is neither statistically nor clinically significant during arthroscopic shoulder surgery. There was no difference in any of the secondary outcomes, including change in pump pressure to improve visualization, total operative time, or intraoperative use of blood- pressure modulating medications. However, there were no adverse events in either group, suggesting that the addition of a preoperative epinephrine injection is safe to perform.