Rate of occurrence of respiratory complications in patients who undergo shoulder arthroplasty with a continuous interscalene brachial plexus block and associated risk factors.

ABSTRACT

INTRODUCTION: Continuous interscalene nerve block techniques are an effective form of targeted non-opioid postoperative analgesia for shoulder arthroplasty patients. One of the limiting risks, however, is potential phrenic nerve blockade with resulting hemidiaphragmatic paresis and respiratory compromise. While studies have focused on block-related technical aspects to limit the incidence of phrenic nerve palsy, little is known about other factors associated with increased risk of clinical respiratory complications in this population. METHODS: A single-institution retrospective cohort study was conducted using electronic health records from adult patients who underwent elective shoulder arthroplasty with continuous interscalene brachial plexus blocks (CISB). Data collected included patient, nerve block, and surgery characteristics. Respiratory complications were categorized into four groups (none, mild, moderate, and severe). Univariate and multivariable analyses were conducted. RESULTS: Among 1025 adult shoulder arthroplasty cases, 351 (34%) experienced any respiratory complication. These 351 were subdivided into 279 (27%) mild, 61 (6%) moderate, and 11 (1%) severe respiratory complications. In an adjusted analysis, patient-related factors were associated with an increased likelihood of respiratory complication ASA Physical Status III (OR 1.69, 95% CI 1.21 to 2.36); asthma (OR 1.59, 95% CI 1.07 to 2.37); congestive heart failure (OR 1.99, 95% CI 1.19 to 3.33); body mass index (OR 1.06, 95% CI 1.03 to 1.09); age (OR 1.02, 95% CI 1.00 to 1.04); and preoperative oxygen saturation (SpO2). For every 1% decrease in preoperative SpO2, there was an associated 32% higher likelihood of a respiratory complication (OR 1.32, 95% CI 1.20 to 1.46, p<0.001). CONCLUSIONS: Patient-related factors that can be measured preoperatively are associated with increased likelihood of respiratory complications after elective shoulder arthroplasty with CISB.