Respiratory failure

Sometimes our lungs cannot do their job.

This means the air we breathe does not get into our blood well. It can also mean bad air stays in the body.

This can make a person feel very confused or sleepy. A person might breathe much faster to try to help. Doctors use special tools to check the blood. They can give extra air to help the body.

This helps the person breathe more easily.

Our lungs help us breathe. They move oxygen into our blood. They also move carbon dioxide out.

Sometimes, this system does not work well. This is called respiratory failure. It means oxygen levels in the blood are too low. This is called hypoxemia. It can also mean carbon dioxide levels are too high. This is called hypercapnia.

There are different types of this condition. Type 1 happens when oxygen is low. This can happen at high altitudes. It can also happen if the lung tissue is damaged. Type 2 happens when both oxygen and carbon dioxide are out of balance. This can be caused by asthma. It can also be caused by problems with muscles.

Doctors look for signs to help. A person might breathe very fast. Their fingers might look bluish. Their fingertips might change shape. This is called clubbing.

Doctors use a test called an arterial blood gas test. This test measures the gases in the blood. They may use a machine called a ventilator to help.

A ventilator is a machine that helps a person breathe.

Our bodies need a constant supply of gases to stay healthy. The respiratory system moves oxygen into the blood and moves carbon dioxide out.

Respiratory failure happens when this gas exchange does not work well. This means oxygen levels in the blood drop too low. This low oxygen state is called hypoxemia. It can also mean carbon dioxide levels rise too high. This buildup is called hypercapnia. When the brain does not get enough oxygen, a person might feel confused or sleepy.

There are different ways this condition works. Type 1 failure happens when oxygen is low but carbon dioxide is normal or low. This can happen at high altitudes where there is less oxygen in the air. It can also happen if lung tissue is damaged by things like pneumonia. Type 2 failure is different because both gases are out of balance. In this type, the body cannot get rid of carbon dioxide. This might happen if the airways are blocked by asthma or if the breathing muscles are weak.

Doctors have identified other specific types as well. Type 3 is a form of Type 1 that happens during or after a surgery. This is often called peri-operative respiratory failure. It can happen because parts of the lung collapse, which is called atelectasis. Type 4 occurs when the body's demand for oxygen is higher than what the heart and lungs can provide. This can happen during shock. These different types help doctors understand exactly what is going wrong.

Doctors look for many signs to help find the cause. A person might breathe much faster than usual. Their skin or lips might look bluish, which is called cyanosis. Sometimes the tips of their fingers change shape; this is called clubbing.

To be sure, doctors use an arterial blood gas test. This is the best way to measure the gases in the blood. They might also use a pulse oximeter to check oxygen levels.

Treating respiratory failure depends on why it started. If an infection is the cause, doctors might use antibiotics. If a person took too much of a drug like an opioid, they might use an antidote called naloxone. For many people, doctors use machines to help them breathe. One tool is a mechanical ventilator.

This machine helps move air in and out of the lungs. Other tools include high-flow oxygen or special masks that provide pressure. Helping the person breathe is the most important first step.

Respiratory failure is a serious medical condition where the respiratory system cannot perform adequate gas exchange. To stay healthy, the body must maintain specific levels of oxygen and carbon dioxide in the blood. In a healthy person, oxygen levels (PaO2) are usually above 80 mmHg (11 kPa). Carbon dioxide levels (PaCO2) are typically less than 45 mmHg (6.0 kPa). When these levels fall out of balance, the body enters respiratory failure. This condition can be acute, meaning it happens suddenly, or chronic, meaning it lasts a long time.

The mechanism of respiratory failure involves the failure to move gases between the air in the lungs and the blood. If oxygen levels in the blood drop, the condition is called hypoxemia. If carbon dioxide levels rise too high, it is called hypercapnia. When the brain does not receive enough oxygen, it can lead to ischemia. This lack of blood flow to the brain can cause an altered state of consciousness, such as confusion or lethargy.

Medical professionals classify respiratory failure into several distinct types. Type 1 respiratory failure is characterized by hypoxemia with normal or low carbon dioxide levels. This type occurs when oxygenation fails. Causes include low ambient oxygen at high altitudes or a ventilation-perfusion mismatch. In a mismatch, parts of the lung receive oxygen but lack enough blood to absorb it. This can be caused by a pulmonary embolism or congestive heart failure. Other causes include diffusion problems from pneumonia or a right-to-left shunt.

Type 2 respiratory failure involves both hypoxemia and hypercapnia. In this type, the body cannot eliminate the carbon dioxide it produces. This is often due to inadequate alveolar ventilation. Common causes include increased airway resistance from asthma or COPD. It can also result from reduced breathing effort due to drug effects or brain stem lesions. Neuromuscular problems, such as Guillain–Barré syndrome, can also prevent the muscles from breathing effectively.

There are also specialized categories known as Type 3 and Type 4. Type 3 is a specific form of Type 1 failure called peri-operative respiratory failure. It is specifically associated with surgery or medical procedures. This often happens because of atelectasis, which is the collapsing of the functional units of the lung. Type 4 respiratory failure occurs when the body's metabolic oxygen demands exceed what the heart and lungs can provide. This often happens during shock, such as cardiogenic or hypovolemic shock.

Doctors use several methods to diagnose the specific cause of the failure. The gold standard is the arterial blood gas (ABG) assessment. This test measures the exact levels of oxygen and carbon dioxide in the blood. Other tools include capnometry, which measures exhaled carbon dioxide, and pulse oximetry. Pulse oximetry measures the fraction of hemoglobin saturated with oxygen. Doctors also look for physical signs like tachypnea, which is a fast breathing rate. They may also notice cyanosis, a bluish color in the fingers or lips, or clubbing of the fingertips.

Treatment focuses on addressing the underlying cause whenever possible. If an infection is the cause, doctors may use antibiotics. If the failure is caused by an opioid overdose, the antidote naloxone is used. For many patients, respiratory therapy is necessary to support breathing. Type 1 failure might require high-flow nasal oxygen or continuous positive airway pressure. Type 2 failure often requires non-invasive ventilation (NIV). In severe cases, doctors use endotracheal intubation and a mechanical ventilator.

The prognosis for respiratory failure varies greatly depending on the cause and how quickly treatment begins. Because the condition can be so severe, it is a major focus of intensive care medicine. One in three hospitalized cases of acute respiratory failure is fatal. Understanding the specific type of failure helps medical teams choose the right tools to restore the balance of gases in the body.