SESSION TYPE: Sleep I
PRESENTED ON: Sunday, October 21, 2012 at 10:30 AM - 11:45 AM
PURPOSE: To assess the predictive values of the OSA risk assessment tool developed by the American Society of Anesthesiologists (ASA) practice guidelines.
METHODS: Patients undergoing general anesthesia from September 2007 to 2009 were evaluated using a preoperative questionnaire based on ASA practice guidelines and scored. Patients with scores ≥5 were identified as high-risk OSA (HR) group and those <5 were identified as low risk (LR). Consequent polysomnography was performed as the gold standard mean of diagnosis. Patients with Apnea/Hypopnea index (AHI>5 per hour) were considered positive for OSA. The patients were followed for development of complications in the postoperative period. Receiver operating characteristics were used to determine the predictive values, sensitivity and specificity of the ASA tool in predicting high-risk OSA and its related complications.
RESULTS: A total of 3593 patients were reviewed and 306 HR patients were identified. Among the HR group, 140/306 patients had an AHI>5/hr, while only 32/306 of LR patients had a positive study. The area under the curve was measured as 0.8. ASA risk tool was found to have 95.1% sensitivity and 52.2% specificity. At a prevalence of 10%, the positive predictive value of this tool was 19% while the negative predictive value 98.5%. The patients in the HR-OSA group were found to have significantly higher incidence of postoperative hypoxia (16.8% vs. 10.2%), and more frequent need for reintubation of the trachea (4.9% vs. 0.9%) when compared to those in the LR-OSA group.
CONCLUSIONS: ASA Guidelines for preoperative risk assessment have a high sensitivity to identify the patients at high risk for OSA. These guidelines were also found to have a relatively lower specificity and positive predictive value for identification of high-risk OSA patients. High-risk OSA patients have a higher incidence of adverse events in the postoperative period compared to their matched controls.
CLINICAL IMPLICATIONS: The ASA questionnaire is a simple and sensitive tool for quick identification of the patients with ASA and predicting resultant respiratory complications.
DISCLOSURE: The following authors have nothing to disclose: Nader Nader, Vandana Sharma, Munish Munish, Jahan Porhomayon
No Product/Research Disclosure InformationUniversity at Buffalo, Buffalo, NY