The effect of norepinephrine versus epinephrine in irrigation fluid on the incidence of hypotensive/bradycardic events during arthroscopic rotator cuff repair with interscalene block in the sitting position

Purpose: To compare the occurrence rate of hypotensive and bradycardic events (HBEs) during arthroscopic rotator cuff\r\nrepair performed with interscalene brachial plexus block anesthesia in the sitting position in 2 groups of patients who\r\nunderwent the procedure with norepinephrine or epinephrine added to the irrigation fluid. The secondary objective was\r\nto evaluate the efficacy of norepinephrine in comparison with epinephrine in controlling intraoperative bleeding and\r\nmaintaining adequate visualization of the arthroscopic field of view during the procedure. We hypothesized that\r\nnorepinephrine added to the irrigation fluid during shoulder arthroscopy in the sitting position would reduce the\r\noccurrence of HBEs, allowing optimal intraoperative bleeding control. Methods: One hundred twenty patients underwent\r\nan arthroscopic rotator cuff repair performed under peripheral anesthesia and in the beach-chair position. Patients\r\nwere randomly divided into 2 groups of 60 cases each: Norepinephrine (0.66 mg/L) and epinephrine (0.33 mg/L) were\r\nadded to irrigation bags in group N and group E, respectively. The primary outcome was the occurrence rate of HBEs\r\nduring surgery. The secondary outcomes were timing of onset of HBEs, accompanying symptoms, and intraoperative\r\nbleeding that impaired arthroscopic visualization. The clarity of the visual field was rated postoperatively by the surgeon\r\nusing a visual analog scale. Comparison between groups for all baseline variables and outcome measurements was performed\r\nwith the c2 or Fisher exact test, as appropriate, for categorical variables and the Student t test or Mann-Whitney U\r\ntest, as appropriate, for continuous variables. Significance was set at P < .05. Results: One patient was excluded from\r\ngroup E because of block failure; therefore 119 patients were finally included in the study. Comparison between groups\r\nshowed no significant differences in baseline characteristics. The occurrence rate of HBEs was significantly greater in group\r\nE (n ¼ 15) than in group N (n ¼ 5) (P ¼ .02). No differences between groups were found in the average time of onset of\r\nHBEs, accompanying symptoms, and clarity of the visual field. Conclusions: Continuous administration of norepinephrine,\r\n0.66 mg/L, diluted in irrigation fluid during arthroscopic rotator cuff repair with the patient in the beach-chair\r\nposition reduces the incidence of HBEs and is as effective as epinephrine in controlling intraoperative bleeding and\r\nmaintaining the visual clarity of the surgical field. Level of Evidence: Level I, randomized clinical study