PURPOSE: Obstructive sleep apnea (OSA) is a risk factor for perioperative cardiopulmonary complications. Available data suggests that postoperative use of positive airway pressure (PAP = CPAP or bilevel pressure support) may reduce complication rates. This study was performed to determine if OSA patients on PAP had significant hypoxemic episodes following surgery and if so, what factors might be predictive.
METHODS: This was a retrospective chart review study at an urban academic center. Patients with PAP-controlled OSA who underwent surgery and used their prescribed PAP in the postoperative setting were included. Lowest O2 saturation during sleep was recorded by continuous pulse oximetry via a standardized alarm-driven nursing protocol. Patients were divided into nocturnal postoperative desaturators (PD, O2 saturation =< 88%) and postoperative nondesaturators (ND). Data was extracted regarding demographics, polysomnograms, medical history, anesthesia, surgery, and postoperative medication use.
RESULTS: 73 patients met criteria for inclusion, 20 (27%) of whom suffered significant postoperative hypoxemic episodes (mean low O2 saturation 79.7%). The PD group had more Caucasians than the ND group, though the groups were similar with regards to age and gender. There were trends towards the PD group being heavier (BMI 45.9 vs. 42.2 kg/m2, p=0.27), having more lung disease (55% vs. 36%, p=0.2) and undergoing longer surgeries (> 2 hrs in 50% vs. 31%, p=0.2), however these were not significant. There was no difference between groups in terms of baseline and post-treatment apnea-hypopnea index, type of PAP (Bi-level vs. CPAP) therapy, PAP settings, type of anesthesia, type of surgery, narcotic or benzodiazepine use, supplemental oxygen use or other co-morbidities.
CONCLUSION: Patients with OSA may become significantly hypoxic during sleep postoperatively even when treated with their prescribed PAP therapy. Factors predicting postoperative nocturnal hypoxia were not found in this small retrospective study.
CLINICAL IMPLICATIONS: In the postoperative period, PAP therapy at prescribed settings may not completely protect OSA patients from nocturnal hypoxemia. Close monitoring of these patients is warranted. The optimal management of OSA patients undergoing surgery needs further study.
DISCLOSURE: Inderjeet Brar, No Financial Disclosure Information; No Product/Research Disclosure Information