Spinal Muscular Atrophy Randomized Controlled Trial on Cough Techniques
(Patient tailored airway clearance in patients with Spinal Muscular Atrophy: a randomized controlled trial comparing air stacking and mechanical insufflation-exsufflation.)

Spinal Muscular Atrophy (SMA) is a neuromuscular (NMD) with progressive
respiratory muscle weakness, resulting in progressive decline of lung function,
impaired cough with recurrent RTIs and finally respiratory failure. Cough
impairment due to respiratory muscle weakness underlies a cycle of events that
contributes to progressive lung function decline: inadequate cough results in
ineffective airway clearance, leading to mucus plugging, atelectasis, and
respiratory tract infections (RTIs). Recurrent RTIs lead to further respiratory
muscle weakness, with a resulting vicious circle. The shortened life
expectancy in SMA is primarily caused by these respiratory problems.
Impaired airway clearance due to weakness of respiratory muscles is common and
represents a challenge in SMA care. Different guidelines suggest to introduce
airway clearance techniques (ACTs) in patients with NMDs when Peak (Expiratory)
Cough Flow (P(E)CF drops below 270 l/min. A very common way to assist both
inspiration and expiration consists in combining assisted inspiration, using
techniques like air stacking (AS), with manually assisted coughing (MAC).
Mechanical insufflation-exsufflation (MI-E) is another technique, which
combines inspiratory and expiratory aids. There is no evidence which of these
ACTs increases P(E)CF most, and results in reduced number of RTIs in this
vulnerable patients.

The aim of this study is to compare the effect of twice daily MI-E to twice
daily AS with MAC on increase of PECF in patients with SMA with weak cough
over a period of 3 years.

Randomized controlled trial. We hypothesize a greater increase in PECF in
patients treated with MI-E compared to AS with MAC

MI-E or AS with MAC should be used at least twice a day

Patients will be visiting the UMCU Utrecht every 4 to 8 months, which will be
in combination with regular visit. During this visit lung function tests will
be done which are the same as during regular follow up, except from measuring
PECF after performing ACT (MIE or AS with MAC). Patients are also requested to
fill a diary on compliance and patient satisfaction once a month. Both AS as
well as MI-E are treatments used during regular care and there are no concerns
regarding safety. Inclusion of children is necessary, as compromised cough
resulting in respiratory tract infections and respiratory failure, is present
from early childhood. In adult patients with severe lung function restriction
for many years, the compliance of the chest is diminished, resulting in less
lung volume recruitment compared to children with shorter disease duration and
for that reason more compliant chest.