Invasive breathing support for SMA

Overview
If noninvasive ventilation (NIV) does not provide enough respiratory support, people with respiratory issues due to spinal muscular atrophy (SMA) may need greater assistance breathing.

With invasive ventilation, a breathing tube is inserted into the body and attached to a mechanical ventilator, also known as a breathing machine. The ventilator helps the person with SMA breathe easier, or breathe more fully than they can on their own.

Decisions to use invasive breathing support are based on the needs of the person with SMA and the course of care chosen. For parents of children with SMA, it’s important to discuss the child’s potential quality-of-life issues with the doctor before opting for this type of breathing support.

In some cases, implantation of the vertical expandable prosthetic titanium rib (VEPTR) may be an option to avoid ventilator dependence. VEPTR is a surgically implanted, FDA-approved expandable device that creates space in the child’s chest so lungs can develop more fully.

What does it involve?
There are two main types of invasive breathing support: an endotracheal tube and a tracheostomy.

An endotracheal tube is inserted through the mouth - or a small hole in the neck - into the lungs, and connected to a ventilator. Known as intubation, it’s typically used with children who need ventilation for shorter periods, such as an illness. The advantage of this tube is that it can be placed in an airway without surgery.

For a tracheostomy, a breathing tube called a “trach” is surgically inserted by making a small hole in the child’s neck, bypassing the mouth and vocal cords, and going directly to the airway (trachea). Trach tubes are used for children who need ventilators for longer periods.

The ventilator machine uses pressure to blow air or a mixture of gases (like oxygen and air) into the lungs. The child can either exhale (breathe out) the air on their own, or the ventilator can exhale for them.

While on a ventilator, a health care team will check the levels of oxygen and carbon dioxide (blood gases) in the child’s body to determine how well the ventilator is working for them. Based on test results, the ventilator's airflow and other settings may be adjusted.

A nurse or respiratory therapist may also suction the breathing tube to remove mucus from the lungs. Suctioning can cause coughing and shortness of breath for several seconds, which can be relieved with extra oxygen.

Nutrients may be fed through a tube inserted into a vein. If on a ventilator for a long time, the child may receive food through a nasogastric, or feeding, tube. The tube may go through the nose or mouth, or directly into the stomach or small intestine, via a surgical incision.

Intended outcomes
The goal of pulmonary intervention in infants with type 1 SMA is to improve quality of life and not necessarily to prolong life. A commitment to lifelong, full-time ventilatory support is an individual choice for the child's family which must be discussed with a multi-disciplinary team including palliative care. A key goal of palliative care is to prevent pediatric intensive care unit stays and avoid tracheotomy, if possible.

Results
There are no clinical trials evaluating outcomes of invasive ventilation in children with SMA. Studies demonstrate that long-term survival is possible, but type of SMA, as well as age at diagnosis, can affect outcomes and must be considered in combination with different ventilation options.

Constraints
Any surgery carries risks including blood clots, blood loss, infection, breathing problems, reactions to medication, and heart attack or stroke during the surgery.

The endotracheal tube can cause damage and irritate the mouth and throat if left in the airway more than a few days to week. A tracheostomy can cause loss of speech and dependency on a ventilator. It also limits socialization and attendance at school. Both types of breathing tubes can damage vocal cords. Using a ventilator also can put the child at risk for lung damage and oxygen toxicity.

A serious and common risk is ventilator-associated pneumonia. Sinus infections are common with endotracheal tubes. Breathing tubes also make it harder to cough. Coughing helps clear airways of lung irritants that can cause infections.

For more details, visit:
1. Breathing Risks – Cure SMA
2. Ventilator Support - National Institutes of Health (NIH)
3. Spinal Muscular Atrophy - Neurologic Clinics
4. Vertical Expandable Prosthetic Titanium Rib (VEPTR) ー Children’s Hospital of Philadelphia
5. Breathing Basics – Cure SMA
6. Spinal muscular atrophy and home ventilation ーCanadian Journal of Respiratory, Clinical Care, and Sleep Medicine