Pulmonary function and nutritional morbidity in children and adolescents with congenital diaphragmatic hernia

Background: Malnutrition is common among congenital diaphragmatic hernia (CDH) survivors and may result from elevated respiratory effort. We evaluated body mass index (BMI), measured resting energy expenditure (mREE) and pulmonary function test (PFT) results in children and adolescents with CDH to determine if there is a correlation.

Methods: With ethics approval (REB# 1000035323), anthropometrics, indirect calorimetry (IC) results and PFTs were collected from patients 5-17years of age during CDH clinic visits between 2000 and 2016. Malnutrition was defined as BMI z-scores <-2.0; mREE (as percent predicted REE) was measured using IC; z-scores for forced expiratory volume in 1s (FEV1) and forced vital capacity (FVC) were normal if <-1.64.

Statistics: GraphPad Prism 6, San Diego, CA.

Results & discussion: Of 118 patients who attended clinic, 33 had reproducible PFTs, anthropometrics and IC results. Mean BMI z-score was -0.89±1.47 and 24% of patients were malnourished; mean FVC z-score (-1.32±1.39) was within normal range, whereas mean z-scores for FEV₁ (-2.21±1.68) and FEV₁/FVC ratio (-1.78±0.73) were below normal. A correlation was noted between BMI and PFTs (FEV₁ r=0.70, P<0.0001; FVC r=0.74 P<0.0001). Mean mREE was 112%±12% of expected and 67% of patients were hypermetabolic (mREE<110% predicted). IC results did not correlate with z-scores for either FEV₁ (r=0.10, P=0.57); or FVC (r=0.28, P=0.12).

Conclusions: These preliminary results suggest that a correlation is present between BMI and lung function in CDH children and adolescents, whereas lung function does not seem to correlate with mREE.

Level of evidence: II.