PURPOSE: Effective CPAP pressure can significantly vary night to night in some patients with Obstructive Sleep Apnea (OSA), depending on body position, alcohol or benzodiazepines consumption, sleep architecture and upper airway permeability. Auto-CPAP machines (ACPAP) are useful to effectively titrate therapeutic pressure.Objective: To determine the variability of mean ACPAP pressures required in 6 consecutive nights on ACPAP in patients with OSA.
METHODS: Patients with polysomnographic (PSG) diagnosis of moderate to severe OSA, treated at home during 6 nights with ACPAP. Pressure profiles, mean and 90th percentile (P90) ACPAP pressure and every night usage were analyzed. The difference between the biggest and the lowest values of mean ACPAP pressure in different nights (rank) was calculated for every subject. Patients were classified in two groups according to their pressure rank, with a cutoff of 2 cmH2O. Both populations were compared.
RESULTS: 177 patients were recruited, 86.4% males, age 55.01 ± 13.3 y/o, BMI 33.7 ± 8.4, AHI 51.2 ± 21.8 ev/h. Patients used their CPAP 5.85 ± 1.28 hs/n with a P90 9.28 ± 2.43 cmH2O. 98 subjects (55.4%) presented a difference in mean CPAP pressure ≥ 2 cmH2O and even 47 of them (26.5%) ≥ 3 cmH2O. When we compared both populations we only found a bigger requirement of CPAP pressure (P90 10.0 vs. 8.3cmH2O; p=0.0001) in patients with a difference ≥ 2cmH2O.
CONCLUSION: More than a half OSA patient have significant variability in ACPAP pressure requirements night to night in a 6 night follow-up.
CLINICAL IMPLICATIONS: These data should be taken into account especially in patients with poor clinical response or a bad compliance, basically if they were titrated in one night basis.
DISCLOSURE: Facundo Nogueira, No Financial Disclosure Information; No Product/Research Disclosure Information