Respiratory distress syndrome is a potentially life-threatening medical condition where the lungs cannot provide enough oxygen for the rest of the body.

Symptoms of respiratory distress syndrome include:

• blue-coloured lips, fingers and toes
• rapid, shallow breathing
• rapid heartbeat

Types of respiratory distress syndrome

There are two main types of respiratory distress syndrome:

• Neonatal respiratory distress syndrome affects newborn babies.
• Acute respiratory distress syndrome can affect people of any age.

Neonatal respiratory distress syndrome

Neonatal respiratory distress syndrome (NRDS) affects premature babies. It can occur if a baby is born before their lungs are fully developed and capable of working properly.

It is estimated that half of all babies born before 28 weeks of pregnancy will develop NRDS.

Acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) mainly affects adults. It occurs when a person’s lungs become seriously damaged and filled with fluid, affecting their ability to breathe in oxygen.

The damage can occur because of:

• an injury to the lungs or a lung infection, such as pneumonia or flu
• an infection that spreads from another part of the body into the blood and then into the lungs (this is a common cause of ARDS)

ARDS mainly affects people over 75 years of age. 

Read more about the causes of respiratory distress syndrome.

Treatment and outlook

Most babies with NRDS can be successfully treated with a medication called artificial surfactant, which helps restore normal lung function. Many cases of NRDS can be prevented by treating the baby before birth with a medication called betamethasone. As a result, death from NRDS is very rare.

ARDS is treated using a ventilator to assist breathing while the underlying cause is treated. As people with ARDS are usually very ill in the first place, there is a high risk of complications, which lead to death in a third of cases. 

Read more about treating respiratory distress syndrome. 

Neonatal respiratory distress syndrome

The symptoms of neonatal respiratory distress syndrome (NRDS) are usually noticeable immediately after birth and get worse over the following 48 to 72 hours.

Symptoms of NRDS include:

• blue-coloured lips, fingers and toes
• rapid, shallow breathing
• flaring nostrils
• a grunting sound when breathing
• the skin around the ribs and chest can appear pulled in, making the bones of the ribs and chest easily visible

Acute respiratory distress syndrome

It is rare for the symptoms of acute respiratory distress syndrome (ARDS) to develop on their own. ARDS usually develops as a complication of a serious, existing health condition (see causes of respiratory distress syndrome). By the time the symptoms of ARDS begin, most people have already been admitted to hospital for another reason.

Symptoms of ARDS include:

• blue-coloured lips, fingers and toes
• rapid, shallow breathing
• breathing that becomes increasingly laboured and difficult
• rapid heartbeat
• tiredness, which is usually followed by drowsiness or confusion

Neonatal respiratory distress syndrome

Neonatal respiratory distress syndrome (NRDS) is caused when there is not enough of a protective substance called surfactant in the lungs. Surfactant is made up of proteins and fats. It helps keep the lungs inflated and prevents the air sacs in the lungs from collapsing.

Your baby will begin to produce surfactant sometime between week 28 and week 32 of pregnancy. Most babies will have produced enough surfactant to breathe normally by week 35 of pregnancy.

If your baby is born before week 35, they may not have enough surfactant in their lungs. If this happens, every time they take a breath, some of the air sacs will collapse.

If the baby is not treated, a large number of air sacs will collapse, causing oxygen levels in the blood to fall. This can lead to multiple organ failure followed by death.

Acute respiratory distress syndrome

Acute respiratory distress syndrome (ARDS) develops if the lungs become very inflamed due to a severe infection or injury. The inflammation causes the air sacs to collapse and fluid from nearby blood vessels to leak into the lungs.

Over time, the lungs will become so full of fluid that breathing becomes increasingly difficult. If it is not treated, ARDS will eventually cause a total loss of lung function and will lead to death.

The lungs may become inflamed due to:

• pneumonia 
• flu (both seasonal flu and swine flu can trigger ARDS in vulnerable people)
• heart failure 
• severe chest injury
• smoke inhalation
• accidental inhalation of toxic chemicals
• drug overdose
• near drowning
• a piece of food or another object accidentally falling down into the lungs
• acute pancreatitis, where inflammation of the pancreas can spread throughout the body

Lung inflammation may occur following an infection that has spread through the blood to affect the whole body.

Inflammation can also occur if you fracture one of your long bones, such as the thigh bone. If fat particles are released, they can travel up into your lungs.

Neonatal respiratory distress syndrome

If your baby is born prematurely, the medical staff will be aware that there is a risk of neonatal respiratory distress syndrome (NRDS). Therefore, it's likely that your baby will be tested for NRDS shortly after being born.

A physical examination will be carried out to check for the distinctive signs and symptoms of NRDS, such as blue lips or flaring nostrils. Blood tests may then be used to measure the amount of oxygen and carbon dioxide in your baby’s blood.

Pulse oximetry test

A pulse oximetry test can also be used to measure how much oxygen your baby is managing to breathe in. A sensor is put on the baby’s fingertip, ear or toe. This measures how light waves are being absorbed.

Oxygen can affect how light waves are absorbed, so by analysing the results the computer can quickly determine how much oxygen is present in your baby’s blood.

X-ray

X-rays of your baby’s chest may also be taken. If your baby has NRDS, the X-rays of the lung will have a distinctive, cloudy appearance.

Echocardiogram

An echocardiogram may be carried out to assess the state of your baby’s heart and to rule out heart conditions that can sometimes cause similar symptoms to NRDS. An echocardiogram is a type of ultrasound scan that is designed to build up a picture of the inside of the heart.

Acute respiratory distress syndrome

The process for diagnosing acute respiratory distress syndrome (ARDS) is similar to that used for diagnosing NRDS.

Blood tests and a pulse oximetry test are used to measure the amount of oxygen and carbon dioxide in the blood and lungs. A chest X-ray may also be used to check the condition of the lungs.

Neonatal respiratory distress syndrome

Treatment for neonatal respiratory distress syndrome (NRDS) often begins before birth. If a woman is thought to have a significant risk of giving birth before week 35 of pregnancy, she will be given an injection of a steroid medication called betamethasone.

Betamethasone helps stimulate the development of the baby’s lungs. It's estimated that the use of betamethasone prevents NRDS occurring in a third of premature births.

Factors that make premature birth more likely include:

• having a previous history of premature birth
• being pregnant with twins or triplets
• having high blood pressure
• having type 2 diabetes

However, in many cases, women without these factors will give birth prematurely.

Treatment after the birth

If betamethasone is unsuccessful in preventing NRDS or if it was not used, it's likely that your baby will be transferred to an intensive care unit (ICU). Your baby will be attached to a ventilator so that their lung function can be supported.

The type of ventilator used will depend on how severe your baby’s symptoms are. In most cases of NRDS, a continuous supply of oxygen is given through a mask that is fitted to your baby’s face.

Your baby will be given a dose of artificial surfactant to help restore their normal lung function and may be given antibiotics as a precaution.

Your baby will also be given fluids and nutrients through a tube connected to one of their veins. Most babies respond well to treatment and are well enough to leave hospital within five to eight days.

Acute respiratory distress syndrome

If you develop acute respiratory distress syndrome (ARDS), you will probably be admitted to an intensive care unit (ICU) and put on a ventilator to assist your breathing. In some cases, it may be possible to use an oxygen mask to supply you with oxygen.

If you have severe ARDS, a tube will be inserted down your throat and into your lungs through which oxygen is pumped. Fluids and nutrients will be supplied through a tube in your vein.

It will also be necessary to treat the causes of ARDS. For example, if it was caused by an infection, you may be prescribed antibiotics to help fight the infection.

The amount of time you need to spend in hospital will depend on your individual circumstances and the cause of ARDS. Most people respond well to treatment within 72 hours, although it may take several weeks or months before you are well enough to leave hospital.

Neonatal respiratory distress syndrome

Complications of neonatal respiratory distress syndrome (NRDS) may develop shortly after treatment begins (acute) or may persist for many years (chronic).

Acute complications

Air leaks

In some cases of NRDS, the use of a ventilator can cause air to leak out of the lungs and become trapped in the chest cavity.

The pocket of air places extra pressure on the lungs so that blood cannot return from the lungs to the heart. This can cause blood pressure to fall and result in further breathing problems.

Air leaks can be treated by inserting a tube into the chest to draw out the trapped air.

Internal bleeding

Babies with NRDS may experience bleeding inside their lungs (pulmonary haemorrhage) and brain (cerebral haemorrhage).

Both are life-threatening conditions that require emergency surgery to repair any damaged blood vessels and stop the bleeding.

Chronic complications

Bronchopulmonary dysplasia

Bronchopulmonary dysplasia (BPD) is a long-term lung condition that can affect some children with NRDS. It develops when the ventilator used to treat NRDS causes the lungs to become scarred, affecting their development.

Symptoms of BPD include, rapid, shallow breathing and shortness of breath.

Babies with BPD usually require an oxygen mask to help with their breathing. This is usually stopped after a few months when the lungs have developed.

However, children with BPD may require regular medication, such as bronchodilators, to help widen the airways of their lungs and assist with their breathing.

Developmental disabilities

If the brain is damaged during NRDS, either through a lack of oxygen or bleeding, it can lead to long-term developmental disabilities such as:

• learning difficulties
• impaired hearing
• impaired vision

These developmental problems are not usually severe. For example, one survey estimated that 3 out of 4 children with developmental problems only have a mild disability that should not affect their ability to lead a normal adult life.

Acute respiratory distress syndrome

Abnormal lung function

Many people with acute respiratory distress syndrome (ARDS) recover normal lung function within six months. However, in some cases, the lungs may become permanently damaged which can lead to symptoms such as:

• extreme tiredness
• chest pain
• shortness of breath, particularly when being physically active

If you have permanent damage to your lungs, you will be prescribed medication, such as bronchodilators, to help with your breathing. In the most severe cases of ARDS, oxygen therapy, such as using a portable oxygen tank to help with breathing, may be required.

Muscle weakness

Muscle weakness affects most people recovering from an episode of ARDS. This is because spending several weeks in bed and on a ventilator can result in a rapid weakening of the muscles.

Once you are discharged from hospital, it is likely that you will require a course of physical therapy, such as strengthening exercises, to regain your muscle strength.

Mental functions

In many cases of ARDS, brain damage can occur due to the brain being starved of oxygen. This can lead to long-term problems with a person’s mental functions, such as memory and learning.

Common problems in people recovering from ARDS include:

• memory problems, such as difficulty recalling certain words or remembering people’s names
• difficulty concentrating
• low attention span
• problems doing complex mental tasks, such as mental arithmetic

Depression

An episode of ARDS can be traumatic and frightening, and the recovery process can sometimes be stressful and frustrating.

As a result, people who are recovering from ARDS often become depressed. It's estimated that a quarter of people recovering from ARDS have moderate to severe depression.

Signs of depression include:

• feeling down or hopeless for extended periods of time
• having little interest or pleasure in doing things you usually enjoy

Contact your GP for advice if you think you may be depressed.