Mechanical limitation during CO2 rebreathing in young patients with cystic fibrosis.
The aim of the study was to determine whether a decrease in the ventilatory response to carbon dioxide (CO2) in children with cystic fibrosis (CF) is related to a mechanical limitation of the respiratory muscle capacity. The ventilatory response during CO2 rebreathing was performed in 15 patients (mean forced expiratory volume in 1 s (FEV1): 37 +/- 21% predicted, mean arterial CO2: 41+/- 5 mmHg). The slope of the minute ventilation normalised for weight per mmHg CO2 increment correlated negatively with respiratory muscle output, assessed by the oesophageal (p = 0.002), the diaphragmatic pressure time product (p = 0.01), and the tension time index (p = 0.005). In addition, this slope was correlated with dynamic lung compliance (p < 0.0001) and FEV1 (p = 0.03) but not with airway resistance and maximal transdiaphragmatic pressure. Therefore, an excessive load imposed on the respiratory muscles explains the blunting of the ventilatory response to CO2 in young patients with CF.
Fauroux
Brigitte
B
Pediatric Pulmonary Department, Armand Trousseau Hospital, Assistance Publique-Hôpitaux de Paris, Paris, France. Brigitte.fauroux@trs.ap-hop-paris.fr
Nicot
Frédéric
F
Boelle
Pierre-Yves
PY
Boulé
Michèle
M
Clément
Annick
A
Lofaso
Frédéric
F
Bonora
Monique
M
D000293:Adolescent; D000328:Adult; D002245:Carbon Dioxide / Q000494:pharmacology*; D002648:Child; D003550:Cystic Fibrosis / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008297:Male; D012123:Pulmonary Ventilation / Q000187:drug effects*; D012119:Respiration / Q000187:drug effects*; D012132:Respiratory Muscles / Q000187:drug effects*
D002245:Carbon Dioxide