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

To develop equations to predict therapeutic continuous positive airway pressure (CPAP_T) based on home-based CPAP titration, including the type of interface used.

Retrospective study conducted in adult patients with obstructive sleep apnea (OSA) who used home-based autoCPAP titration (AutoSet S10, ResMed^®). CPAP_T was obtained manually through a visual analysis of autoCPAP data (CPAP_V) and automatically using the 95th percentile pressure (CPAP_P95). 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.

We included 702 patients (174 women), median age, BMI and AHI of 58 years, 32 kg/m² and 32 ev/h, respectively. Predictors for CPAP_v (M1) were BMI, NC, AHI and type of interface (R²: 0.19); and for CPAP_P95 (M2), BMI, AHI and mask (R²: 0.09). Error and precision between the formulas and CPAP_T were: 0 (CPAP_V/CPAP_P95), and - 3.2 to 3.2 (CPAP_V) and - 4 to 4 cm H₂O (CPAP_P95). CPAP_V 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 CPAP_T was greater in M1 than in M2 (79% vs. 64%, p < 0.01).

In both models, calculated error was close to zero. CPAP_V (± 3.2 cm H₂O) showed more precision than CPAP_P95 (± 4 cm H₂O). With M1 (CPAP_V), 79% of patients could start CPAP with reasonable accuracy (error of ± 2 cm H₂O).