Respiratory Care and Ventilation for Spinal Muscular Atrophy

People with spinal muscular atrophy (SMA) have progressive muscle weakness. Chest muscles that support breathing are often especially affected. This can lead to breathing problems because of undeveloped lungs, weak coughing, and higher risk of lung infections. Respiratory failure is a leading cause of death in children with type 1 or 2 SMA.

Respiratory care is an important part of managing SMA. It is led by a pulmonologist (a doctor who specializes in lung care). Respiratory care plans are specific to each person depending on severity. Respiratory care in SMA aims to keep the airway clear and support breathing, especially during sleep.

Why do people with SMA need respiratory care?

Muscle weakness in the chest makes it difficult to cough. A weak cough makes it harder to clear mucus and other secretions from the airway. This can lead to blockages and difficulty breathing. Throat muscle weakness also makes it more difficult to swallow. This increases the risk of breathing liquids or food into the lungs (aspiration) and can lead to lung infection (pneumonia).¹

Chest muscle weakness also prevents lungs from fully developing. Over time, the lungs of children with SMA do not grow to normal size and strength. Muscles normally relax during sleep, which can cause problems for people with SMA. This can cause slow or shallow breathing (hypoventilation) when the lungs do not take in enough oxygen. Hypoventilation during sleep is an early sign of breathing difficulties.¹

What respiratory care is common for people with SMA?

Respiratory care is important for survival and quality of life. Recognizing breathing problems early can help get the best care as quickly as possible.^1,2

After diagnosis, families should discuss a respiratory care plan with their doctor. This doctor will often be a pulmonologist who specializes in lungs and breathing. They will assess breathing and coughing abilities. They will also offer tips to keep the airway clear, perform breathing exercises, and support breathing.²

Children with type 1 SMA usually require more respiratory care than children with type 2 SMA. People with type 3 SMA usually have normal breathing function. However, respiratory care goals are specific to each person with SMA. Some parts of respiratory care include:³

Airway clearance

People with SMA will be tested often for coughing ability. Doctors will suggest ways to improve coughing. For example, a cough machine can be used to improve cough strength by pushing air out of the lungs. Caregivers can also perform manual cough assistance by putting upward pressure on the abdomen during coughing.^1,3

Making mucus looser can also help children with SMA cough out. This is called “secretion mobilization.” Some techniques used to clear mucus from the airways include:^1,3

• Chest physiotherapy – Using hand techniques to loosen secretions
• Postural drainage – Positioning children at an incline to pull secretions from the lungs
• Intrapulmonary percussive ventilation (IPV) – Using air pressure to loosen secretions

Ventilation

People with SMA will be regularly monitored for their breathing during sleep. Doctors and caregivers may perform other tests to monitor lung function, such as chest X-rays or pulse oximetry.³

Many children with SMA need breathing support, or “ventilation.” Ventilation can either be non-invasive or invasive. Non-invasive ventilation uses devices on or outside the body. These techniques are often used during sleep.^3,4

A common non-invasive ventilation technique is bi-level positive airway pressure (BiPAP). The machine provides air pressure through a face mask based on the breathing cycle. Other types of mechanical ventilators are also used.¹

Invasive ventilation uses devices inside the body. A breathing tube is usually attached to a breathing machine (mechanical ventilator). The tube will be placed into the body for direct access to the lungs. Two types of breathing tubes are:^1,3

• Endotracheal tubes, which go through the mouth and are meant for temporary use
• Tracheostomy tubes, which go through a small hole in the neck for long-term use

Talk to your doctor about all ventilation options. Families of children with severe types of SMA may face tough decisions about respiratory care. At some point, non-invasive ventilation may not provide enough support. Whether to maintain long-term invasive ventilation or transition to palliative (comfort-focused) care is a very personal and difficult decision.

Care during colds

Respiratory infections can lead to serious breathing problems for people with SMA. Talk to your doctor about how to provide respiratory care during a cold. Usually, it will include:¹

• Close monitoring of blood oxygen levels
• Cough assistance and secretion mobilization techniques every few hours
• More breathing support than normal

A potentially serious infection is respiratory syncytial virus (RSV). For most children, RSV is like a bad cold. But for children with SMA, RSV can lead to serious breathing problems. A drug called Palivizumab can help prevent RSV infection.⁵