Formulas to predict continuous positive airway pressure level using a home auto-adjusting device for obstructive sleep apnea treatment.

ABSTRACT

PURPOSE: To develop equations to predict therapeutic continuous positive airway pressure (CPAPT) based on home-based CPAP titration, including the type of interface used. METHOD: Retrospective study conducted in adult patients with obstructive sleep apnea (OSA) who used home-based autoCPAP titration (AutoSet S10, ResMed®). CPAPT was obtained manually through a visual analysis of autoCPAP data (CPAPV) and automatically using the 95th percentile pressure (CPAPP95). Multiple linear regression and K-fold cross-validation were applied. Independent variables were AHI, neck circumference (NC), BMI, and mask. Two formulas were generated based on mask and the Miljeteig and Hoffstein formula. RESULTS: We included 702 patients (174 women), median age, BMI and AHI of 58 years, 32 kg/m2 and 32 ev/h, respectively. Predictors for CPAPv (M1) were BMI, NC, AHI and type of interface (R2 0.19); and for CPAPP95 (M2), BMI, AHI and mask (R2 0.09). Error and precision between the formulas and CPAPT were 0 (CPAPV/CPAPP95), and - 3.2 to 3.2 (CPAPV) and - 4 to 4 cm H2O (CPAPP95). CPAPV was higher with oronasal mask (10 vs. 9 cm H2O, p < 0.01). Accuracy defined as; a difference ± 2 cm H2O between estimated CPAP and CPAPT was greater in M1 than in M2 (79% vs. 64%, p < 0.01). CONCLUSION: In both models, calculated error was close to zero. CPAPV (± 3.2 cm H2O) showed more precision than CPAPP95 (± 4 cm H2O). With M1 (CPAPV), 79% of patients could start CPAP with reasonable accuracy (error of ± 2 cm H2O).