Respiratory therapy for SMA

Overview
Weak respiratory muscles can make it difficult for people with spinal muscular atrophy (SMA) to cough and clear mucus from their lungs, which puts them at higher risk for severe respiratory infections and complications.

A pulmonologist or respiratory care therapist can train people with SMA or their carers to perform airway clearance techniques (ACTS) to help strengthen coughing and loosen mucus. Many of these therapies can be done at home either manually or with a portable device.

Breathing and respiratory issues are the most common cause of death in children with type 1 or 2 SMA. For this reason, a pediatric pulmonologist should be part of your multidisciplinary SMA care team, consulted as soon as possible after diagnosis.

What does it involve?
Regular respiratory function tests are required for people with SMA-related breathing problems. People with SMA type 1 and 2 are typically evaluated every three to six months; those with type 3 may be seen less often.

During these visits, and specifically when an individual is sick, pulmonologists may recommend one or a combination of manual and mechanical therapies to keep airways clear.

Coughing assistance aims to create a stronger cough, so mucus can be expelled.

Cough assistance therapies may include:

Mechanical cough-assist machine. Also known as an insufflator-exsufflator machine, this non-invasive device blows air into the lungs, then sucks it out quickly. The goal is to mimic a strong coughing effect that increases the amount of mucus expelled. The machine is marketed under various brand names including CoughAssist.

Manual cough assistance. This hands-on technique involves placing gentle upward pressure on a person’s abdomen and diaphragm as they cough. It helps move the diaphragm up and create stronger exhalation and coughing. Mucus that’s released can be suctioned out of the mouth or swallowed.

Mucus mobilization is designed to loosen and expel stuck sputum. Mucus clearance therapies include:

Chest physiotherapy. Also known as manual or mechanical percussion, this technique involves gently clapping on the chest wall (or using a vibrating device) to loosen mucus. Some people with SMA may need it every day, others only when they’re sick.

Postural drainage. This therapy involves placing a child on an incline with pillows or wedges, head lowered, to encourage mucus to move upward. Gravity pulls secretions from lower airways into the upper airways, where they can be removed by suctioning or coughing.

Intrapulmonary percussive ventilation (IPV). This device, marketed under the brand name Percussionaire, pushes small bursts of air and saline mist into the lungs at a set frequency. The continuous flow of air loosens trapped mucus making it easier to cough or suction out.

High frequency chest-wall oscillation (HFCWO). Marketed under various brand names, including InCourage, an HFCWO device is a wearable vest that vibrates to help move out mucus.

Your doctor will discuss how to use respiratory therapies at home, as well as how often they should be used. During an illness, it may be necessary to use respiratory therapies more often.

Intended outcome
The goals of non-invasive ACTs are promoting airway clearance and removing secretions to ease breathing and reduce risk of infections, pneumonia, and other complications.

Results
A 2018 review of the existing evidence for ACTs for people with neuromuscular disorders suggested that these therapies have reduced frequency of infections, pneumonia, and hospitalizations in people with SMA.

Constraints
The use of ACTs is not advisable in people with uncontrolled asthma or bronchospasm, rib fractures, pregnancy, history of lung disease, cervical spine injury, unstable chest pain, or head and neck injury.

The American Association for Respiratory Care (AARC) warns against using vest therapy in the presence of reflux from tube feeding or a recent meal, existing pulmonary disease or surgery, pulmonary edema or embolism, uncontrolled hypertension, or complaint of chest wall pain.

Risks of mechanical cough or airway clearance machines include pneumothorax (air leak in the lungs), worsening reflux, and food entering the airway. Manual cough therapy may be ineffective in people with severe scoliosis.

The cost and availability of respiratory experts in primary care, the geographical location of people needing assistance, and care coordination may lead to poor care quality. Some devices are considered experimental and not covered by insurance.

For more details, visit:
1. Breathing Basics - CureSMA
2. Spinal Muscular Atrophy Medical Management – Muscular Dystrophy Association
3. Airway clearance techniques in neuromuscular disorders: A state of the art review ー Respiratory Medicine
4. The Vest®️ Airway Clearance System 一 Hill-Rom
5. How to use a mechanical insufflator-exsufflator ー Breathe