When a person has acute respiratory failure, the usual exchange between oxygen and carbon dioxide (CO2) in the lungs does not occur. As a result, the heart, the brain, or the rest of the body cannot get sufficient amounts of oxygen.

Acute respiratory failure occurs when the air sacs of the lungs cannot release enough oxygen into the blood. This can be due to fluid buildup, hardening of the air sac walls, asthma-induced muscle spasms, and many other conditions that affect lung function.

Respiratory failure can cause symptoms such as shortness of breath, a bluish tint in the lips and face, and confusion. If a person thinks they or someone else has it, they should seek immediate medical attention.

In this article, we detail the types of acute respiratory failure, their causes, symptoms, and treatments.

Doctors typically classify acute respiratory failure as one of two types: hypoxemic or hypercapnic.

Hypoxemic respiratory failure

In this type of the condition, there is not enough oxygen in a person’s blood. This is due to a failure in oxygen exchange in the lungs, which can result from swelling of the lungs or fluid buildup.

A person experiencing this will still have stable CO2 levels in their blood.

Hypercapnic respiratory failure

A person with hypercapnic respiratory failure will have higher levels of CO2 in their blood. Their blood oxygen levels may remain steady or be lower than usual.

Hypercapnic respiratory failure occurs when the lungs’ alveoli, or air sacs, cannot adequately excrete CO2 that the body produces.

Acute vs. chronic

Respiratory failure can be acute or chronic. Acute respiratory failure will occur suddenly and require immediate medical attention. This may be due to direct injury or rapid changes in lung function.

By contrast, chronic respiratory failure is an ongoing condition that develops over time and will typically require long-term treatment.

Generally, symptoms of acute respiratory failure depend on the underlying cause and may include changes in a person’s appearance, ease of breathing, and behavior.

The following are examples of possible symptoms:

Acute respiratory failure usually stems from difficulty getting enough oxygen to the lungs, problems removing CO2 from the lungs, or both. This can be due to tissue damage, fluid buildup, muscular spasms, or other physical processes.

Potential causes include:

Determining the cause of acute respiratory failure helps a doctor determine the most appropriate treatments.

The above conditions and events can increase a person’s risk of acute respiratory failure.

Moreover, babies born prematurely with underdeveloped lungs have a higher risk of acute respiratory failure due to pulmonary hypertension and neonatal respiratory distress.

Older adults may also be more likely to experience acute respiratory failure due to an increased susceptibility to infection and a weakening of the lung muscles.

Other risk factors for acute respiratory failure include:

  • recreational alcohol or drug use, which can increase the risk of overdose
  • exposure to irritant chemicals, such as in the workplace
  • severe allergies

To diagnose acute respiratory failure, a doctor will consider a person’s symptoms and often order a range of tests.

These tests may include:

By assessing the gas levels in a person’s blood, a doctor will be able to determine whether acute respiratory failure is hypoxemic or hypercapnic.

Imaging tests will allow them to check for physical obstructions in the lungs, such as:

  • swelling
  • cancerous growths
  • fluid buildups

A doctor may order additional tests to rule out other potential causes of shortness of breath. These tests may include:

Acute respiratory failure can lead to a range of complications, some of which can be fatal. These include:

  • permanent damage or scarring to the lungs
  • infections, such as sepsis
  • heart damage
  • neurological complications from a lack of oxygen
  • kidney damage

Treatments for acute respiratory failure depend on the underlying cause. However, most people with acute respiratory failure are likely to require extra oxygen as an initial course of treatment.

Doctors typically use this method of delivering oxygen until they can slow down the progression of, resolve, or reverse the underlying cause of respiratory failure.

In the short term, an individual may also require:

A doctor may also prescribe medications to sedate a person, making breathing with the ventilator easier to tolerate.

Not all causes of acute respiratory failure, such as trauma, are preventable.

However, in the case of pneumonia and some other airway-related conditions, a person can take some steps to protect their lungs.

These include:

If an individual has a history of lung problems and hospitalization, they should discuss with a doctor strategies to enhance their overall health.

Learn more about how to support lung health here.

Acute respiratory failure is a serious medical condition that has many possible underlying causes.

Symptoms include confusion, rapid breathing, and shortness of breath.

Seek immediate medical attention at the first signs of respiratory failure to prevent the condition from worsening.