Clinical predictors of obstructive sleep apnea

Objective: To identify physical findings that can be standardized to predic t the presence and the severity of obstructive sleep apnea (OSA), Study Des ign: One hundred seventy-two patients who answered questionnaires with resp onses that suggested they might have OSA were included in this prospective study. Methods: All patients underwent a physical examination and polysomno graphy, The physical examination included the measurement of four parameter s used by anesthesiologists to identify patients likely to have difficult i ntubation to determine if these same parameters predict OSA. We recorded mo dified Mallampati grade (MMP), tonsil size, and body mass index (BMI) and m easured thyroid-mental distance (TMD) and hyoid-mental distance (HMD) in th e study population. Results: When the physical findings were correlated sin gly with the respiratory disturbance index (RDI), we found that MMP (P < .0 01), tonsil size grading (P = .008), and BMI (P = .003) were reliable predi ctors of OSA. A greater correlation with OSA emerged when an "OSA score" wa s formulated by factoring the MMP, tonsil grade, and BMI grade (RDI = 7.816 x MMP + 3.988 x Tonsil Size + 4.675 x BMI 7.544). A high score was not onl y predictive of OSA but also correlated well with OSA severity. Neither HMD nor TMD correlated with the severity of RDI, Conclusions: An OSA score may help identify those patients who should have a full sleep evaluation.