The use of structured light plethysmography in children with neuromuscular disease

Abstract

Background: Children with neuromuscular disorders (NMD) require non-invasive ventilation (NIV) and cough assist (CA) technology to live longer. The new SLP measures chest wall expansion allowing measurement of relative contribution to ventilation of both the right versus left lung and the chest versus abdomen. To use Structured Light Plethysmography (SLP) to optimise chest expansion therapies (optimising NIV or CA) we need to know the repeatability and relative contribution of right versus left and chest versus abdomen in controls and patients. Methods: Repeated SLP tidal breathing relative contribution of right versus left chest wall and total chest versus abdomen movement was measured in 15 controls and 22 NMD patients. Results: The mean normal Right versus Left contribution was 50/50% (most extreme 47/53%) with tight repeatability. In patients (some with scoliosis) the range was wider (50-69%) with less repeatability. The mean normal chest contribution was 59/41% (chest/abdomen) with evidence of greater abdominal contribution (55/45%, chest/ abdomen) in patients. We studied one child with NMD and scoliosis immediately before, during and after NIV therapy. In this child the Right contribution was 43% and the Left was 57%. While on NIV the contributions became 50/50%. There was no change in the chest/abdominal contributions. Conclusion: SLP tidal breathing measurement looks a promising tool for optimising NIV and CA settings in children with NMD.