CPAP vs BiPAP: Differences and How to Choose

What these devices do

In obstructive sleep apnea, the throat muscles relax during sleep and the airway narrows or closes. Breathing stops and starts, and the person wakes briefly many times without realising it.

CPAP and BiPAP devices blow positive-pressure air through a mask. The air acts like a splint that holds the airway open through the night. Diagnosis and pressure settings are a doctor's job, usually based on a sleep study.

CPAP, Auto CPAP and BiPAP compared

CPAP (fixed pressure): one pressure all night, for breathing in and out. Simple, and a good fit once the doctor knows the required pressure.

Auto CPAP (APAP): adjusts pressure automatically within a range the doctor sets, raising it when the airway starts to narrow and lowering it when it is not needed. It suits people whose pressure needs change with sleep position or sleep stage.

BiPAP (bilevel): a higher pressure when breathing in (IPAP) and a lower one when breathing out (EPAP), which makes exhaling easier. S/T mode adds timed backup breaths if the patient does not breathe enough on their own.

In short:

• One known pressure: CPAP
• Pressure needs vary through the night: Auto CPAP
• Difficulty exhaling against pressure, or pressure support needed: BiPAP

The choice is the doctor's. This guide is only meant to help you understand the options.

When doctors choose BiPAP

Doctors often consider BiPAP when:

• The patient cannot tolerate the CPAP pressure they need because exhaling feels hard.
• High pressures are needed, and dropping the pressure on exhalation makes therapy more comfortable.
• The patient has a condition that calls for pressure support, not just keeping the airway open.

BiPAP is used at home and on the ward, but it does not replace a ventilator for patients who need invasive ventilation. Never switch from CPAP to BiPAP, or change the pressure, without talking to the doctor.

Making therapy comfortable

Therapy only works if the device is used every night. Common problems and what helps:

Mask leaks or soreness: masks come in several styles, including nasal masks, nasal pillows and full-face masks. Try different ones until one fits, and tighten the straps just enough, not more.

Dry nose or throat: a heated humidifier helps a lot. The Resvent Auto CPAP has one built in.

Feeling smothered when falling asleep: some devices can start at a low pressure and build up gradually. Ask the doctor about the settings.

Not knowing whether it works: devices that log data, such as the Resvent Auto CPAP II with SD card logging, let the doctor review hours of use and leak and fine-tune the settings.

Hygiene: wash the mask, tubing and water chamber as the manufacturer instructs, and replace consumables on schedule.

Resvent devices we supply

• Resvent CPAP: fixed pressure, 4 to 20 cmH₂O.
• Resvent Auto CPAP: auto-titrating 4 to 20 cmH₂O with an integrated heated humidifier.
• Resvent Auto CPAP II: SD card data logging and enhanced leak compensation.
• Resvent BiPAP: S/T mode, IPAP 4 to 30 and EPAP 4 to 25 cmH₂O.

Thunder Venture Group supplies hospitals, sleep clinics and patients at home, with delivery across all 77 provinces and a set-up walkthrough at handover.

Frequently Asked Questions