What is respiratory failure?
Respiratory failure is a condition where you don’t have enough oxygen in the tissues in your body (hypoxia) or when you have too much carbon dioxide in your blood (hypercapnia). You might also hear people use the term “acute hypoxemic respiratory failure (AHRF)” to describe it.
Respiratory failure is often a medical emergency. Call 911 or seek medical attention right away if you think you’re experiencing respiratory failure.
How respiration works
You can think of respiration as passengers traveling from the air to your tissues. When you breathe in, oxygen molecules travel to your lungs — the passengers arriving at the airport. The oxygen passengers arrive at the “airport gates” — small air sacs around your lungs called alveoli — and are picked up by your blood. They travel through your blood to their final destination in your tissues, like your organs and muscles. You need oxygen to reach its destination to stay alive.
After your blood cells drop off oxygen in your tissues, they have room to pick up carbon dioxide. Your body doesn’t need carbon dioxide (it’s a waste product). If too much of it builds up, there isn’t room in your blood’s transportation system to deliver oxygen. Your blood circulates through your body, back to your lungs, where it drops off carbon dioxide. When you breathe out, you get rid of the unnecessary waste to make room for more oxygen.
If any parts of this system fail, you won’t have enough oxygen to keep your tissues healthy.
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What are the types of respiratory failure?
Respiratory failure can come on suddenly (acute) or over time (chronic). There are two common types: hypoxemic respiratory failure (type 1) and hypercapnic respiratory failure (type 2). Other types include perioperative (related to surgery) respiratory failure (type 3) and respiratory failure due to shock (type 4).
Hypoxemic respiratory failure
Hypoxemic respiratory failure happens when you don’t have enough oxygen in your blood (hypoxemia). Heart and lung conditions are the most common causes. Hypoxemic respiratory failure is also called hypoxic respiratory failure.
Hypercapnic respiratory failure
Hypercapnic respiratory failure happens when you have too much carbon dioxide (CO2) in your blood. If your body can’t get rid of carbon dioxide, a waste product, there isn’t room for your blood cells to carry oxygen.
The most common causes of hypercapnic respiratory failure include heart, lung, muscle and neurological (brain and spinal cord) conditions. Certain medications can also cause it. Hypercapnic respiratory failure is also called hypercarbic respiratory failure.
Perioperative respiratory failure
Perioperative respiratory failure can happen when you have surgery. Anesthesia (medication that keeps you asleep) can keep you from breathing properly. Sometimes, air sacs in your lungs can collapse (atelectasis) and keep oxygen from getting into your blood.
Respiratory failure due to shock
Shock is a condition that causes low blood pressure, fluid in your lungs (pulmonary edema) and other issues that can lead to respiratory failure. Sepsis, cardiac events (like a heart attack) and blood loss can cause shock.
