Introduction Continuous positive airway pressure (CPAP) therapy is the standard treatment for obstructive sleep apnoea (OSA), however, patients frequently have sub-optimal long-term adherence. We hypothesised that bilevel positive airway pressure (BPAP) therapy may improve adherence and outcomes in patients who cannot tolerate CPAP.

Methods Patients with OSA who had sub-optimal CPAP usage (<4hours/day) and were referred to our sleep centre between 2014–2017 for BPAP were included. Age, gender, body-mass-index (BMI), co-morbidities, CPAP use and reasons for failure, Epworth Sleepiness Score (ESS), sleep study data, spirometry data and average maximum nightly compliance were recorded.

Results We included 52 patients with OSA who required CPAP>15cmH20 (71% male, age 58 (15) years, BMI 42.6 (10.1) kg/m2, AHI 51.1 (30.4)/hour); 62% had respiratory co-morbidities affecting nocturnal breathing (COPD, OHS). CPAP was used for 199 (106–477) days prior to referral. Reasons for CPAP failure were intolerance of pressures (23%), uncontrolled symptoms (23%), mask problems (21%), adverse effects (13%), claustrophobia (8%), co-morbidities (8%), and other issues (4%). Lower expiratory positive airway pressures (EPAP) were needed to control nocturnal breathing compared to CPAP (10 (8–12) vs 16.8 (15.7–19.2) cmH20, p=0.001) and patients achieved better adherence (7.0 (4.0–8.5) vs 2.5 (1.6–6.7) hours/night, p=0.028) and better symptom control (ESS 4.0 (1.0–7.0) vs 10.0 (6.0–17.0) points, p=0.039) on BPAP.

Discussion In patients with OSA with limited success on CPAP therapy, BPAP is better tolerated and achieves sufficient respiratory and symptom control.