Daytime predictors of nocturnal hypercapnic hypoventilation in children with neuromuscular disorders

Abstract

Objectives To examine objective daytime predictors of nocturnal hypercapnic hypoventilation (NHH) and identify a forced vital capacity (FVC) z‐score cut off that predicts NHH using the 2012 Global Lung Function Initiative (GLI) reference equations in pediatric neuromuscular patients. Design Single‐centre retrospective medical record review. Setting Tertiary pediatric hospital in Australia. Patients Children (<18 years old) with a neuromuscular disorder (NMD) who had a diagnostic sleep study over a 5‐year period. Results Fifty children were included, median age 11.9 years (interquartile range [IQR]: 4.5–14.3). The majority of children had a diagnosis of Duchenne Muscular Dystrophy (32%). NHH was diagnosed in 18 children (36%). Multivariate logistic regression analysis performed for the entire cohort confirmed a statistically significant association between NHH and scoliosis (odds ratio [OR]: 3.3, p = 0.03), but not age (OR: 1.01, p = 0.26), body mass index z‐score (OR: 0.86, p = 0.26) or use of a wheelchair for mobility (OR: 1.25, p = 0.72). For the subset of 29 children who had spirometry testing (median age 12.9 years [IQR: 10.2–14.3]), FVC z‐score was the only statistically significant predictor of NHH (OR: 0.45, p = 0.02). NHH was predicted by an FVC z‐score <−3.24 (sensitivity 78%, specificity 73%), or FVC <60% predicted (sensitivity 78%, specificity 73%). There was a strong positive correlation between FVC and forced expiratory volume in 1 s z‐scores (rp = 0.98, p = 0.00) and FVC and peak expiratory flow z‐scores (rp = 0.72, p = 0.00). Conclusion Children with a NMD and scoliosis or a lower FVC z‐score have increased odds of having NHH.

Daytime predictors of nocturnal hypercapnic hypoventilation in children with neuromuscular disorders—The Holy Grail

“…Whilst the results presented by Frohlich et al 14 In terms of pulmonary function, the results of this study also showed that the expiratory muscle strength (expressed as mean peak expiratory flow) was significantly reduced in the presence of NHH, suggesting an associated higher risk of ineffective cough in these patients.…”

“…Whilst the results presented by Frohlich et al 14 add relevant information to the clinical management of children with NMD, some aspects of the current study highlight how complicated it is to obtain a straightforward association between pulmonary function decline and NHH.…”

“…In their retrospective study, Frohlich et al 14 have tried to identify an FVC z-score cut-off, using the 2012 Global Lung Function Initiative reference equations in pediatric NMD to predict NHH, which was defined as per the 2012 American Academy of Sleep Medicine (AASM) criteria a transcutaneous CO 2 (TcCO 2 ) >50 mmHg for over 25% of total sleep time (TST). 17 The authors included 50 patients.…”

“…The study by Frohlich et al 14 addresses relevant clinical questions, however, some longstanding issues are very current and still remain open.…”

Pediatric pulmonology year in review 2022: Sleep medicine

“…However, the studies also highlighted some limitations of using the FVC score alone to detect NHH and recommended early screening for NHH even in individuals with FVC > 50%. Frohlich et al 41 found that scoliosis and a decrease in FVC were important predictive factors for NHH. Children with an FVC z‐score <−3.24 had a sensitivity and specificity of 78% and 73%, respectively, for the detection of NHH.…”