Home Philips CPAP CPAP vs ASV


CPAP and ASV machines are similar but different devices used to treat sleep apnea disorders. ASV machines can reduce apnea events. However, they’re contraindicated and carry risks for certain people. ASV machines can also have serious side effects, and some models have been recalled.

Last Modified: September 7, 2023
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What Are Key Differences Between CPAP and ASV Machines?

Continuous positive airway pressure and adaptive servo-ventilation machines both treat sleep apnea disorders. They use pressurized air but deliver it differently.

A Philips CPAP machine, for example, delivers continuous and fixed air pressure at a level predetermined by a health care professional. An ASV machine monitors the patient’s breathing pattern in real time and dynamically adjusts air pressure to adapt to the user’s needs.

Research indicates that switching from a CPAP to an ASV machine improves adherence and device usage.

How Are ASV and CPAP Machines Similar?

ASV and CPAP machines deliver a continuous flow of pressurized air throughout the breathing cycle to treat various sleep apnea disorders. This continuous flow helps people maintain open airways and reduce or eliminate pauses in breathing.

CPAP and ASV machines are noninvasive treatments delivered through a mask worn over the nose, mouth or both. They don’t require any surgical procedures or invasive interventions.

ASV and CPAP machines can have serious side effects. Some models have been subject to product recalls and lawsuits.

Should I Use an ASV Device?

Doctors primarily recommend ASV machines for individuals diagnosed with specific sleep-related breathing disorders, including:
  • Central sleep apnea
  • Complex sleep apnea
  • Narcotic-induced sleep apnea
  • Sleep apnea related to high altitude
  • Systolic heart failure with Cheyne-Stokes breathing and ejection fraction above 45%.

Doctors may also recommend an ASV device for patients with obstructive sleep apnea who develop central sleep apnea when treated with CPAP, bi-level positive or auto-positive airway pressure.

While sometimes used as alternatives to CPAP machines, ASV machines are also contraindicated for specific cases, including:
  • Individuals with certain severe neuromuscular disorders or respiratory disorders, such as severe restrictive lung disease, that affect respiratory muscles
  • Patients with systolic heart failure who have a left ventricular ejection fraction below 45% and predominant central sleep apnea
  • Patients who are obese, have recently had serious heart or lung surgery and have a low functional residual capacity (the amount of air left in the lungs after a normal exhalation)

The suitability of ASV machines as CPAP machine alternatives should be assessed by a health care professional, taking into consideration the specific diagnosis, medical history and overall health of the patient.

Lawsuit Information
Respiratory problems and multiple types of cancer are among the possible CPAP side effects named in Philips lawsuits.
View Lawsuits

Are ASV Devices Effective?

For the right patients, ASV therapy can effectively treat sleep apnea that’s resistant to CPAP therapy. ASV machines can reduce the number of apnea events and alleviate CPAP machine side effects, leading to better overall sleep quality and daytime functioning.

Research indicates that ASV machines are more protective for patients requiring mechanical ventilation during surgery and more effective at treating opiate-induced central sleep apnea than CPAP machines. 

Studies also found that ASV therapy does not increase the use of health care services in patients with central sleep apnea. However, ASV machines carry serious side effects and risks and are not suitable for all patients with sleep apnea.

Side Effects and Risks of ASV Machines

The side effects of ASV machines are similar to CPAP machines, including stomach bloating and abdominal discomfort, dry eye, ear pressure and pain, reduced face growth in children, insomnia, nasal dryness or inflammation, respiratory infections, skin irritations and tooth chipping or shifting. 

Most side effects are mild and recede over time or with minimal intervention. However, the side effects of Philips CPAP machines prompted a device recall that included Philips ASV machines. The polyester-based polyurethane (PE-PUR) foam used in these devices can break down and pose a potential health risk. The Philips ASV and CPAP recall warns of potentially serious or life-threatening side effects, including:

  • Allergic and skin reactions
  • Airway inflammation, which is especially dangerous for people with lung disease or reduced breathing capacity
  • Asthma
  • Chest pressure
  • Cough
  • Dizziness
  • Headache
  • Hypersensitivity reactions
  • Irritation of the respiratory tract, eyes, nose and skin
  • Nausea or vomiting
  • Organ damage, such as liver problems or kidney problems
  • Respiratory issues
  • Sinus infection
  • Various cancers

Some people who used recalled devices are filing Philips CPAP lawsuits, claiming Philips manufactured a defective device and failed to adequately warn of the risk. 

Talk to your health care provider if you’re experiencing side effects from an ASV machine. They can ensure your equipment functions properly, adjust your machine’s settings and propose alternative treatments.

Please seek the advice of a medical professional before making health care decisions.