Extended Overnight Monitoring of Respiratory Events after Bariatric Surgery

Introduction: Patients receiving bariatric surgery are at risk for sleep apnea (OSA) and need extensive surveillance in the postoperative period. There is evidence of respiratory events (RE) several hours after leaving PACU. We analyzed the late onset of RE in patients recovering from bariatric surgery and their opiate requirements through the first night after surgery. Methods: We studied 52 patients with OSA and 38 non-OSA patients. Preoperative studies comprised meticulous OSA evaluation for all patients and computing the predictive score PRODIGY to stratify for the risk of RE. All patients received intraoperative multimodal non-opioid anesthesia. After PACU recovery, patients were admitted to a ward and continuously monitored for pulse oximetry, heart rate, and acoustic respiratory rate for up to 18 h using MASIMO RAD-97 and TRACE software (Masimo, USA). Results: All patients showed a progressing reduction in the frequency of RE after admission to the floor. Desaturations and bradypnea, however, increased significantly for a second peak between 14 and 16 h in the OSA group. The opiate doses administered to OSA and non-OSA patients were not different and remained low during the increases in RE. Discussion: After bariatric surgery, patients with OSA show significant late-desaturation and bradypnea events. Opiate administration cannot be invoked as the cause.