Which patients are candidates for BPAP (Bilevel Positive Airway Pressure) therapy in Obstructive Sleep Apnea Syndrome (OSAS)?

Aim: CPAP is recommended as the standard treatment for OSAS. Those who fail CPAP therapy may benefit from alternative non-invasive positive pressure ventilation methods, primarily BPAP. The aim of this study is to identify patient characteristics and polysomnographic parameters that may predict CPAP failure and the need for BPAP therapy in OSAS. Materials and Methods: In our study, data were collected from patients diagnosed with OSAS at the Van YYÜ Dursun Odabaş Medical Centre Polysomnography Unit between 01.01.2013 and 01.07.2024 , data were retrospectively obtained from patient files for patients who achieved success in CPAP titration and those who failed CPAP titration but responded to BPAP titration. These data were statistically analysed using SPSS 25.0 software. Results: According to the results obtained from the study, comorbidities such as heart failure, COPD, atherosclerosis, hyperlipidemia, hypertension, diabetes mellitus, Parkinson's disease, and Cushing's syndrome were more prevalent in the BPAP group. The BMI (body mass index) value of the patients in the BPAP group (35,88 ± 7,08) was statistically significantly higher compared to the value in the CPAP group (30,47 ± 6,27) (p<0,001). When the groups were compared in terms of the first night's polysomnography data, the BPAP group had statistically significantly higher Total AHI value (55,41 ± 28,76 vs. 31,39 ± 21,35, respectively; p<0,001) and Non-REM AHI value (56,28 ± 29,54 vs. 32,33 ± 22,21, respectively; p<0,001) compared to the CPAP group. Additionally, the BPAP group had statistically significantly higher oxygen desaturation index value (52,27 ± 30,03 vs. 29,81 ± 23,96, respectively; p<0,001) and percentage of sleep time spent below SPO2 90 value (64,92 ± 34,49 vs. 39,49 ± 34,09, respectively; p<0,001) compared to the CPAP group. Furthermore, the BPAP group had statistically significantly lower average SPO2 throughout the night value (84,11 ± 8,67 vs. 89,43 ± 3,40, respectively; p<0,001) and lowest SPO2 throughout the night value (67,62 ± 12,49 vs. 77,53 ± 8,95, respectively; p<0,001) compared to the CPAP group. In the logistic regression analysis conducted to identify independent variables that could predict the need for BPAP treatment in OSAS patients, BMI (OR: 1,114; 95% CI: 1,024–1,213; p=0,012) and the percentage of sleep time spent below SPO2 90 (OR: 1,021; 95% CI: 1,008–1,035; p=0,002) were identified as statistically significant independent variables. Conclusion: In our study, compared to the CPAP group, the BPAP group had more comorbidities, and the values of BMI, Total AHI, Non-REM AHI, oxygen desaturation index, and percentage of sleep time spent below SPO2 90 were higher, while the values of average SPO2 throughout the night and lowest SPO2 throughout the night were lower. BMI and the percentage of sleep time spent below SPO2 90 were identified as independent variables in predicting the need for BPAP treatment. Although these parameters, especially BMI and the percentage of sleep time spent below SPO2 90, are considered potential predictors of CPAP failure and the need for BPAP treatment, prospective, multicenter studies with larger sample sizes are needed in the future.