Proposal of a diagnostic algorithm based on the use of pulse oximetry in obstructive sleep apnea

Purpose The aims of this study were to assess the cut-off values for oxygen desaturation index > 3% (ODI3) to confirm obstructive sleep apnea (OSA) in subjects undergoing polysomnography (PSG) and home-based respiratory polygraphy (RP), and to propose an algorithm based on pulse oximetry (PO) for initial management of patients with suspected OSA. Methods This was an observational, cross-sectional, retrospective study. ODI3 was used to classify subjects as healthy (no OSA = AHI < 5 or < 15 events/h) or unhealthy (OSA = AHI >= 5 or >= 15 events/h). On the PSG or experimental group (ExpG), we determined ODI3 cut-off values with 100% specificity (Sp) for both OSA definitions. ODI3 values without false positives in the Exp-G were applied to a validation group (Val-G) to assess their performance. A strategy based on PO was proposed in patients with suspected OSA. Results In Exp-G (PSG) 1141 patients and in Val-G (RP) 1141 patients were included. In Exp-G, ODI3 > 12 (OSA = AHI >= 5) had a sensitivity of 69.5% (CI95% 66.1-72.7) and Sp of 100% (CI95% 99-100), while an ODI3 > 26 had a 53.8% sensitivity (CI95% 49.3-58.2) and Sp of 100% (CI95% 99.4-100) for AHI >= 15. A high pretest probability for OSA by Berlin questionaire (> 2 categories) had a lower diagnostic performance than by STOP-BANG questionnaire >= 5 points (AHI > 5: 0.856 vs. 0.899, p < 0.001; AHI >= 15: 0.783 vs. 0.807, p 0.026). Conclusion We propose the initial use of PO at home in cases of moderate-to-high pretest probability of OSA. This algorithm considers PO as well as RP and PSG for more challenging cases or in case of doubt.