Auto-adjusting CPAP Titrations at Home and Correlation between an Automatic Algorithm and the Hoffstein Formula

ABSTRACT

Introduction: Continuous positive airway pressure (CPAP) has proven to be effective in the treatment of obstructive sleep apnea/hypopnea syndrome (OSAHS). Effective pressure is traditionally acquired with a polysomnography (PSG). The performance of unconventional strategies, such as auto-adjusting positive airway pressure (APAP) and titration formulas (Tf) varies according to the population where they are applied. Objective: To describe the APAP titration and correlate the mean airway pressure (Meanp), the Effp and the Hoffstein and Mateika Tf pressure (Hofff). Results: We included 192 patients, 52 female (27%) and 140 male; age, 60.2 years old ± 11.7 and BMI (body mass index) of 33.8 ± 6.7 kg/m2. The apnea-hypopnea index (AHI) was 33.1 ± 16.6 in females and 36.5 ± 16 in males (p > 0.24); and 190 cases (98.9%) had an AHI > 15 ev/hour. Mean compliance with APAP was 380 minutes ± 101 in females and 370 ± 91.2 in males (p > 0.54). Less than 10% of the population presented unacceptability criteria. We found a correlation between the Meanp and the Effp; rho 0.73 (95% CI [confidence interval] 0.57-0.84) p < 0.001. However, between the Effp and the Hofff ß 0.519 and r2 0.269 (p < 0.001) there was an underestimation by Hofff - 1.98 cm H2O (95% CI, 1.48-2.49) and intraclass correlation index 0.60 (95% CI 0.47-0.80) p < 0.0001. Conclusions: A high proportion of patients titrate at home with APAP without supervision and with acceptability criteria. We did not find a suitable correlation between the Hofff and the Effp in our population