Changes in ventilation distribution in children with neuromuscular disease using the insufflator/exsufflator technique: an observational study.

Patients with neuromuscular disease often suffer from weak and ineffective cough resulting in mucus retention and increased risk for chest infections. Different airway clearance techniques have been proposed, one of them being the insufflator/exsufflator technique. So far, the immediate physiological effects of the insufflator/exsufflator technique on ventilation distribution and lung volumes are not known. We aimed to describe the immediate effects of the insufflator/exsufflator technique on different lung volumes, forced flows and ventilation distribution. Eight subjects (age 5.8-15.2 years) performed lung function tests including spirometry, multiple breath washout and electrical impedance tomography before and after a regular a chest physiotherapy session with an insufflator/exsufflator device. Forced lung volumes and flows as well as parameters of ventilation distribution derived from multiple breath washout and electrical impedance tomography were compared to assess the short-term effect of the therapy. In this small group of stable paediatric subjects with neuromuscular disease we could not demonstrate any short-term effects of insufflation/exsufflation manoeuvres on lung volumes, expiratory flows and ventilation distribution. With the currently used protocol of the insufflation/exsufflation manoeuvre, we cannot demonstrate any immediate changes in lung function.