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

PURPOSE

To develop equations to predict therapeutic continuous positive airway pressure (CPAP) 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). CPAP was obtained manually through a visual analysis of autoCPAP data (CPAP) and automatically using the 95th percentile pressure (CPAP). 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/m and 32 ev/h, respectively. Predictors for CPAP (M1) were BMI, NC, AHI and type of interface (R: 0.19); and for CPAP (M2), BMI, AHI and mask (R: 0.09). Error and precision between the formulas and CPAP were: 0 (CPAP/CPAP), and - 3.2 to 3.2 (CPAP) and - 4 to 4 cm HO (CPAP). CPAP was higher with oronasal mask (10 vs. 9 cm HO, p < 0.01). Accuracy defined as; a difference ± 2 cm HO between estimated CPAP and CPAP was greater in M1 than in M2 (79% vs. 64%, p < 0.01).

CONCLUSION

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