BiPAP Machines (BiLevel) for Sleep Apnea

How BiPAP Machines Work

Where a standard CPAP machine delivers one continuous pressure all night, a BiPAP machine uses two distinct pressure settings that alternate with every breath. The higher pressure — called IPAP (inspiratory positive airway pressure) — supports your airway as you breathe in. The lower pressure — EPAP (expiratory positive airway pressure) — makes breathing out noticeably easier by reducing resistance. This dual-pressure design makes BiPAP therapy significantly more comfortable for people who require higher pressures, or for those whose breathing pattern doesn't respond well to continuous fixed pressure.

BiPAP is most commonly prescribed for central or complex sleep apnoea, obstructive sleep apnea requiring high pressure, obesity hypoventilation syndrome (OHS), and respiratory conditions such as COPD. Some BiPAP models also include a backup respiratory rate — a setting that triggers a breath if the machine detects that breathing has paused or slowed, which is particularly important for central sleep apnea management.

Understanding BiPAP Therapy Modes

BiPAP machines are available in several different modes, and your prescription will specify which one is right for your condition:

BiPAP S (Spontaneous) — The most common mode for obstructive sleep apnea. The machine delivers bilevel pressure in response to your own breathing efforts, with no backup rate. Suitable when the patient can reliably initiate their own breaths.

BiPAP ST (Spontaneous-Timed) — Includes a timed backup breathing rate, delivering a breath if none is detected within a set interval. Used for central sleep apnea, COPD, and conditions where breathing may stop or become insufficient without intervention.

BiPAP Auto (ASBF / VAuto) — An auto-adjusting bilevel mode that varies both IPAP and EPAP within prescribed ranges in response to breathing in real time. Often prescribed for complex sleep apnea or when optimal pressure levels aren't yet fully determined.

Your prescribing specialist will specify the appropriate mode and pressure settings for your machine. Once you've placed your order, you can upload your prescription through our website and we'll configure the machine before dispatch. For further guidance, visit our CPAP machines FAQ.

Frequently Asked Questions

What is the difference between BiPAP and CPAP?

A CPAP machine delivers one constant pressure throughout the night. A BiPAP machine delivers two alternating pressures — a higher pressure on the inhale and a lower pressure on the exhale. This makes BiPAP significantly more comfortable for people who need higher therapy pressures, as exhaling against continuous high pressure can be difficult and disruptive to sleep. BiPAP is also the appropriate therapy for certain conditions that CPAP doesn't address effectively, including central sleep apnea and sleep-related hypoventilation. If you've been prescribed CPAP but are finding exhalation uncomfortable, it's worth speaking with your sleep specialist about whether bilevel therapy might be more suitable — alternatively, some patients find that an Auto Pressure (APAP) machine with an expiratory pressure relief feature resolves the issue without requiring a BiPAP.

Do I need a prescription to buy a BiPAP machine in Australia?

Yes — a prescription is mandatory for BiPAP machines. Unlike auto pressure or fixed pressure CPAP machines, BiPAP therapy involves more complex pressure settings (IPAP, EPAP, and where applicable, a backup rate) that must be specified by a qualified sleep specialist or respiratory physician based on your diagnosis. Once you have your prescription, you can upload it through our website and we'll programme your machine to the prescribed settings before it ships. If you're accessing therapy through NDIS or DVA, our team can assist — get in touch with us to discuss your options.

How do I know which BiPAP mode I need?

Your sleep specialist or respiratory physician will specify the required mode — S, ST, or Auto — as part of your prescription, based on your diagnosis and the results of your sleep study. You don't need to determine this yourself. If you've been given a prescription that specifies a BiPAP device but you're unsure which mode it refers to, contact the clinician who issued it for clarification before purchasing. Our team is also happy to assist you interpret your prescription details — visit our FAQ or get in touch directly.