Risk factors associated with hypotensive bradycardic events during open shoulder surgery in the beach chair position

Background: Shoulder surgery in the beach chair position frequently causes hypotensive bradycardic events (HBEs), which are potentially associated with an increased risk of cerebral hypoperfusion. Here, we aimed to investigate the incidence and characteristics of symptomatic HBEs that require pharmacological interventions, and to identify specific risk factors associated with symptomatic HBEs. Methods: We retrospectively examined the records of all patients aged ≥ 18 years who underwent shoulder arthrotomy in the beach chair position between January 2011 and December 2018 at Samsung Medical Center. For patients who experienced HBEs while in the beach chair position, the minimum heart rate and systolic blood pressure were noted, as was the total dose of ephedrine or atropine. Results: Symptomatic HBEs occurred in 61.0% of all cases (256/420). Two patients with symptomatic HBEs experienced postoperative neurological complications. Multivariable logistic regression analysis showed that preoperative interscalene brachial plexus block (ISB) and advanced age were risk factors associated with symptomatic HBEs (odds ratio [OR]: 3.240, 95% CI: 2.003, 5.242, P <0.001; OR: 1.060 for each 1-year increase, 95% CI: 1.044, 1.076, P < 0.001, respectively). Receiver operating curve analysis revealed that a threshold of 62 years of age had a moderate degree of accuracy for predicting symptomatic HBEs (area under curve: 0.764, 95% CI: 0.720, 0.804, P < 0.001). Conclusions: Considering the increasing risk of neurocognitive complications with aging, proactive hemodynamic management is needed, especially for elderly patients undergoing shoulder surgery in the beach chair position using ISB.