RESUMO
BACKGROUND: Severe obstructive sleep apnea (sOSA) and oxygen desaturations are both risk factors for postoperative complications. In some but not all patients, sOSA is associated with frequent oxygen desaturation episodes during sleep. The aim of this retrospective study was to identify the risk factors for exhibiting oxygen desaturation in patients with sOSA. METHODS: Records of 786 patients, mainly obese (Body Mass Index [mean+SD]=30.2+6.0 kg/m2), were analyzed. Univariate and multivariate analyzes were applied to identify predictive risk factors for oxygen desaturation. Prediction probability was used to test the association between potential risk factors (obesity, age, gender, smoking, alcohol consumption, and benzodiazepines use) and the combination of sOSA and oxygen desaturation. A P value <0.05 was considered as statistically significant. RESULTS: Univariate and multivariate analyses identified five risk factors for oxygen desaturation in the whole population: age (P<0.001), obesity (P<0.001), benzodiazepine use (P<0.001), smoking (P=0.016), and male gender (P=0.029). The same analyses applied to patients with sOSA identified two independent risk factors for oxygen desaturation: obesity (P<0.001), and benzodiazepine use (P=0.017). Obesity obtains the best prediction probability [95% CI] for the combination of sOSA and oxygen desaturation: 0.74 [0.69-0.79]. A BMI >49 kg/m2 was associated with a 50% probability of combining severe OSA and nocturnal oxygen desaturation. CONCLUSIONS: Less than 50% of patients with sOSA experience nocturnal oxygen desaturation. Obesity and daily benzodiazepine intake are independent risk factors for these patients to exhibit nocturnal oxygen desaturation. Benzodiazepine in obese patients with sOSA should, therefore, be used cautiously.
