Overview
Respiratory failure is a condition in which the level of oxygen in the blood becomes dangerously low or the level of carbon dioxide in the blood becomes dangerously high.
Respiratory failure happens when the capillaries, or tiny blood vessels surrounding your air sacs, cannot properly exchange carbon dioxide and/or oxygen.
There are two types of respiratory failure: acute and chronic.
Acute respiratory failure happens suddenly. It occurs due to a disease or injury that interferes with the ability of the lungs to deliver oxygen or remove carbon dioxide. In most cases, acute respiratory failure can be fatalTrusted Source if not treated quickly.
Chronic respiratory failure has multiple causes. It can occur when the airways narrow or become damaged over time. It can also occur with conditions that cause the respiratory muscles to weaken over time.
- Conditions that block the airways, damage lung tissue, weaken the muscles that control breathing, or decrease the drive to breathe may cause respiratory failure.
- People may be very short of breath, have a bluish coloration to the skin, and be confused or sleepy.
- Doctors use a fingertip sensor (pulse oximetry) to detect low levels of oxygen and blood tests to detect high levels of carbon dioxide in the blood.
- Oxygen is given.
- Sometimes people need the help of a machine to breathe (mechanical ventilation) until the underlying problem can be treated.
Acute respiratory failure is a medical emergency that can result from
- Long-standing lung disease that suddenly gets worse
- Severe lung disease that develops suddenly in otherwise healthy people
Causes
Almost any condition that affects breathing or the lungs can lead to respiratory failure. Respiratory failure can occur in two ways:
- The level of oxygen in the blood becomes too low (hypoxemic respiratory failure).
- The level of carbon dioxide in the blood becomes too high (hypercarbic respiratory failure).
Low oxygen level (hypoxemic respiratory failure)
An abnormality of the lung tissue, such as acute respiratory distress syndrome, severe pneumonia, an abundance of fluid in the lungs (for instance, due to heart failure or kidney failure), or lung scarring, is a frequent cause of hypoxemic respiratory failure. The natural ability of the lung tissues to absorb oxygen from the air is interfered with by such anomalies.
When a blood clot stops a lung artery, for example, irregular blood flow across the lungs can also result in hypoxemic respiratory failure (pulmonary embolism). The normal ability of the lung tissues to absorb oxygen is not affected by this illness, but oxygen cannot be adequately removed from the air without blood flowing to a portion of the lungs.
High carbon dioxide level (hypercarbic respiratory failure)
With hypercarbic respiratory failure, the level of carbon dioxide is too high usually because something prevents the person from breathing normally. Common examples of such causes include the following:
- A low level of thyroid hormone (hypothyroidism)
- Sleep apnea
- Sedation due to an overdose of opioids or alcohol
- Blockage or narrowing of the airways
- Injury to the lungs
- Damage to bones and tissues around the lungs
- Weakness of muscles that normally inflate the lungs
The unconscious urge that propels people to breathe is diminished by hypothyroidism, sleep apnea, an overdose of alcohol or opiates, and all of these conditions. Disorders (such asthma and chronic obstructive pulmonary disease) and inhaled foreign particles can cause blockage or narrowing of the airways. Breathing obstruction and hypercarbic respiratory failure can result from injuries to the chest or lungs, as well as from weak chest muscles (as in persons with myasthenia gravis, Guillain-Barre syndrome, or amyotrophic lateral sclerosis [ALS]).
Low oxygen levels are common in people who are having trouble breathing, but if they do not also have a lung tissue problem, they are not regarded as having hypoxemic respiratory failure.
Who is at risk for acute respiratory failure?
- smoke tobacco products
- drink alcohol excessively
- have a family history of respiratory disease or conditions
- have an injury to the spine, brain, or chest
- have a compromised immune system
- have chronic respiratory conditions, such as lung cancer, COPD, or asthma
What Causes Respiratory Failure?
| Underlying Problem | Cause |
|---|---|
| Abnormality of the chest wall | A chest wound, deformities resulting from chest surgery, injury, extreme obesity, or scoliosis |
| Abnormality of lung tissue | Acute respiratory distress syndrome (ARDS), a drug reaction, pneumonia, pulmonary edema (excess fluid in the lungs) due to heart failure or kidney failure, pulmonary fibrosis, radiation, sarcoidosis, or widespread tumors |
| Airflow obstruction | Asthma, bronchiectasis, bronchiolitis, chronic obstructive pulmonary disease (COPD), cystic fibrosis, or inhaled foreign objects |
| Muscle weakness | Amyotrophic lateral sclerosis (ALS), certain strokes, Guillain-Barré syndrome, muscular dystrophy, myasthenia gravis, polio, polymyositis, or spinal cord injury |
| Poor breathing (decrease in the drive to breathe) | Drug or alcohol intoxication, hypothyroidism, obesity, or sleep apnea |
Symptoms
Similar symptoms are frequently present in hypoxemic respiratory failure and hypercarbic respiratory failure. Most people have severe breathing problems. Shortness of breath and cyanosis, a bluish colouring of the skin in light-skinned persons, as well as gray or whitish coloring in the mouth, around the eyes, and under the nails in dark-skinned people, are symptoms of low oxygen levels in the blood. Confusion and sleepiness are caused by low oxygen levels, high carbon dioxide levels, and rising blood acidity.
If the urge to breathe is normal, the body will attempt to expel carbon dioxide by breathing deeply and quickly. This breathing rhythm, however, could be ineffective if the lungs are unable to operate correctly. Ultimately, the heart and brain begin to malfunction, causing irregular heart rhythms (arrhythmias) and eventual death by sleepiness (often to the point of unconsciousness).
The cause can affect some respiratory failure symptoms. People may be exceedingly tired, breathe too slowly, and gently fall into a coma if their desire to breathe is aberrant (for instance, after taking too much alcohol or sedatives).
Diagnosis
- Measurements of the amount of oxygen and carbon dioxide in the blood
- Chest x-ray and other tests to determine the cause
On the basis of the symptoms and results of the physical examination, a doctor can detect respiratory failure.
Pulse oximetry, a method that measures blood oxygen levels without drawing blood, involves applying a sensor to a finger or earlobe.
When a test on a sample of blood obtained from an artery reveals a dangerously low level of oxygen and/or a dangerously high quantity of carbon dioxide, it is concluded that the patient has respiratory failure.
To identify the cause of respiratory failure, examinations including chest x-rays and others are frequently performed.
Complications
Because acute respiratory failure means your organs are not receiving the oxygen-rich blood they need to function, complications can involve multiple organ systems. Acute respiratory failure can oftenTrusted Source be fatal.
Pulmonary complications, or those affecting the lungs, can include:
- pulmonary embolism
- pulmonary fibrosis
- pneumonia
- pneumothorax (collapsed lung)
Other complications can include:
- gastrointestinal hemorrhage
- renal (kidney) failure
- hepatic (liver) failure
Treatment
- Supplemental oxygen
- Mechanical ventilation
- Treatment of the cause
People with acute respiratory failure are treated in an intensive care unit (ICU).
Any oxygen deficiency in persons with respiratory failure is treated with additional oxygen. Depending on how much oxygen is required, either a face mask or a small plastic prong put in the nose (a nasal cannula) can be used to administer oxygen. Usually, more oxygen than is required is provided at first, and then the amount is decreased.
Those with hypercarbic respiratory failure can improve their lung ventilation (and lower their carbon dioxide levels) by using mechanical ventilation. A device (ventilator) is used in mechanical ventilation to assist airflow into and out of the lungs.
Doctors often try noninvasive methods first, but invasive mechanical ventilation may be necessary unless respiratory failure resolves rapidly with noninvasive treatment. Most people with respiratory failure are treated with both supplemental oxygen and some kind of mechanical ventilation.
The underlying disorder causing the respiratory failure must be treated. For example, antibiotics are used to fight pneumonia caused by bacterial infection, and bronchodilators are used in people with asthma to open the airways. Other drugs may be given, for example, to decrease inflammation or treat blood clots.