BiPAP vs CPAP: differences, indications & price

BiPAP vs CPAP: what are the differences and when to choose each?

CPAP (continuous positive airway pressure) is the reference treatment for obstructive sleep apnea. But some patients require more sophisticated therapy: BiPAP (BiLevel Positive Airway Pressure), which operates with two distinct pressure levels. Understanding the difference between these two devices is essential for making the right therapeutic choice.

How does CPAP work?

A CPAP delivers a single constant pressure (or variable in the case of auto CPAP) during both inhalation and exhalation. This pressure keeps the upper airways open and prevents the collapses responsible for obstructive apneas. It is the first-line treatment for the vast majority of sleep apnea patients.

How does BiPAP work?

A BiPAP device delivers two different pressures:

• IPAP (Inspiratory Positive Airway Pressure): higher pressure during inhalation to keep airways open
• EPAP (Expiratory Positive Airway Pressure): lower pressure during exhalation to ease breathing out

The difference between IPAP and EPAP (called "pressure support" or PS) can be adjusted to match each patient's ventilation profile. Some BiPAPs include a backup breathing rate for patients whose spontaneous respiration is insufficient.

Comparison table: CPAP vs BiPAP

Who needs a BiPAP?

BiPAP is prescribed in specific situations where CPAP is insufficient or not tolerated:

• High CPAP pressure (above 14-15 cmH₂O): some patients find it hard to exhale against such high pressure. BiPAP reduces expiratory pressure, improving comfort and adherence.
• Central sleep apneas (CSA): unlike obstructive apneas, central apneas result from a failure of the brain's respiratory control. Certain BiPAP-ST or adaptive servo-ventilation (ASV) devices are indicated here.
• COPD (chronic obstructive pulmonary disease): COPD patients often experience nocturnal hypoventilation that benefits from BiPAP's inspiratory support.
• Obesity hypoventilation (Pickwick syndrome): severely overweight patients may hypoventilate at night, where BiPAP is more appropriate.
• Neuromuscular diseases: ALS, muscular dystrophy, advanced multiple sclerosis - BiPAP helps support failing respiration.
• CPAP intolerance at high pressure: when the patient can no longer tolerate exhaling against high pressure, BiPAP can be considered.

BiPAP subtypes for central apneas

• BiPAP-S (Spontaneous): triggered by the patient's spontaneous breathing - for patients who breathe on their own
• BiPAP-ST (Spontaneous-Timed): includes a backup rate if breathing stops - for patients at risk of central apneas
• BiPAP-ASV (Adaptive Servo-Ventilation): continuously adjusts pressures to treat complex central apneas, including Cheyne-Stokes syndrome

Who decides: CPAP or BiPAP?

Your pulmonologist or sleep specialist prescribes the appropriate device type based on your diagnosis. If you feel discomfort exhaling with your current CPAP, do not directly purchase a BiPAP without a consultation - your doctor may first explore other solutions (pressure reduction, EPR feature, adapted mask).

CPAP devices available at VivaRespire

• ResMed AirSense 11 AutoSet
• Philips DreamStation 2
• Löwenstein Prisma SMART Auto

Browse our auto CPAP and BiPAP / BiLevel categories.

Reimbursement and convention in Belgium

In Belgium, the RIZIV/INAMI convention provides access to a CPAP or BiPAP device on loan from an accredited centre - the patient never owns the device. VivaRespire offers direct purchase outside the convention, making you the owner of your equipment. For full details: CPAP reimbursement Belgium.