References: Fauroux et al, 1998
Respir Physiol Neurobiol. 2006 Oct 27;153(3):217-25. Epub 2005 Dec 27.
Mechanical limitation during CO2 rebreathing in young patients with
cystic fibrosis.
Fauroux B, Nicot F, Boelle PY, Boulé M, Clément A, Lofaso F, Bonora M.
Pediatric Pulmonary Department, Armand Trousseau Hospital, Assistance
Publique-Hôpitaux de Paris, Paris, France.
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.