Lung function changes with initiation of non-invasive ventilation (NIV) in childhood duchenne muscular dystrophy

Abstract

Introduction: The use of non-invasive ventilation (NIV) support in children has increased over the past decade. The aim of this study was to describe and analyse Lung Function (LF) changes with initiation NIV in children with Duchenne Muscular Dystrophy (DMD). Methods: A retrospective clinical audit of children with DMD who were initiated on NIV in the past 10 years was conducted. Serial LF data was collected for individuals in the 4 years before and following NIV initiation. The rates of decline in LF were calculated by fitting a regression model to the combined data using the generalized estimating equations method to allow for repeat measures on patients. The influence of long-term steroid use was explored. Results: 27 male patients with DMD initiated NIV during the study period at median age 14.67 years (IQR 2.41 years). Eight boys (29.6%) were long-term steroid users from a median age 7 years and 6 (22.2%) boys were steroid naive. The age NIV started was 14.26 years (IQR 3.82) for the steroid treated group, and 14.87 years (IQR 2.33) for the steroid naive group, with no statistical difference (p = 0.44). 26 children had >2 PFT before (121 tests), and 26 had >2 PFT after initiating NIV (109 tests). The rate of decline in FVC % predicted pre-NIV was-7.14% (95% CI-8.30 to-6.09) and post-NIV was-5.68% (95% CI-6.91 to-4.46), p < 0.05. The total AHI on diagnostic sleep study had median 8.3 (IQR 12.8) and maximum TcCO2 50.4 mmHg (IQR 8.8). When NIV was initiated a significant reduction in total AHI (p < 0.001) to 1.9 (IQR 3.7) and TcCO2 (p < 0.001) to 46.5 mmHg (IQR 6.1) was seen. 2 of the 27 children were deceased at time of writing. Conclusion: The rates of decline in FVC are higher in boys with DMD prior to NIV than they are following NIV initiation, however, long-term steroid use does not affect the age when NIV is needed in DMD.L6246119392018-11-01 <br />