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