Effects of Obesity and Sex on Ventilatory Constraints during a Cardiopulmonary Exercise Test in Children.

PURPOSE: Ventilatory constraints are common during exercise in children, but the effects of obesity and sex are unclear. The purpose of this study was to investigate the effects of obesity and sex on ventilatory constraints (i.e., expiratory flow limitation (EFL) and dynamic hyperinflation) during a maximal exercise test in children. METHODS: Thirty-four 8-12-year-old children without obesity (18 females) and 54 with obesity (23 females) completed pulmonary function testing and maximal cardiopulmonary exercise tests. EFL was calculated as the overlap between tidal flow-volume loops during exercise and maximal expiratory flow-volume loops. Dynamic hyperinflation was calculated as the change in inspiratory capacity from rest to exercise. RESULTS: Maximal minute ventilation was not different between children with and without obesity. Average end-inspiratory lung volumes (EILV) and end-expiratory lung volumes (EELV) were significantly lower during exercise in children with obesity (EILV: 68.8 ± 0.7%TLC; EELV: 41.2 ± 0.5%TLC) compared with children without obesity (EILV: 73.7 ± 0.8%TLC; EELV: 44.8 ± 0.6%TLC; P < 0.001). Throughout exercise, children with obesity experienced more EFL and dynamic hyperinflation compared with those without obesity (P < 0.001). Also, males experienced more EFL and dynamic hyperinflation throughout exercise compared with females (P < 0.001). At maximal exercise, the prevalence of EFL was similar in males with and without obesity, however the prevalence of EFL in females was significantly different with 57% of females with obesity experiencing EFL compared with 17% of females without obesity (P < 0.05). At maximal exercise, 44% of children with obesity experienced dynamic hyperinflation compared with 12% of children without obesity (P = 0.002). CONCLUSIONS: Obesity in children increases the risk of developing mechanical ventilatory constraints such as dynamic hyperinflation and EFL. Sex differences were apparent with males experiencing more ventilatory constraints compared with females.

A 63-year-old Woman With Rapidly Progressive Interstitial Lung Disease.

CASE PRESENTATION: A 63-year-old Japanese woman with no medical history presented as an outside hospital transfer for further management of acute hypoxemic respiratory failure. Per her family, the patient had developed a rash and intermittent shortness of breath 2 months prior to hospital presentation. The rash was described as an erythematous maculopapular rash located on her proximal arms, chest, and upper eyelids. She saw her primary care physician, who prescribed a course of oral and topical corticosteroids. Despite these symptoms, the patient had an excellent functional status and exercised several times per week without muscle weakness. Two months following the initial presentation, the patient progressively became lethargic, prompting her son to bring her to the hospital for admission and evaluation. While in the hospital, the patient had progressive shortness of breath and developed worsening hypoxemic respiratory failure. Despite broad-spectrum antibiotics, her hypoxemia worsened, requiring intubation. She was subsequently started on 80 mg of IV methylprednisolone three times daily and transferred to our institution for further management. The patient arrived from the outside hospital receiving deep sedation and paralysis. Despite maximal ventilator settings, the patient remained hypoxemic and developed shock requiring multiple vasopressors.