The ventilatory response to carbon dioxide in asthmatic children, measured by the mouth-occlusion method (Pm100)
Cosgrove, J.F.; Neuburger, N.; Levison, H.
Pediatrics 57(6): 952-959
1976
ISSN/ISBN: 0031-4005 PMID: 934752 Document Number: 100194
Ventilatory responses to CO2 varied widely in patients with bronchial asthma; some had a high response despite increased airway resistance. This paradoxical response was studied in 31 asthmatic children and 22 age-matched healthy children. Measurement of the ventilatory response to CO2 with a conventional rebreathing method showed wide variation in the patients, paralleling the degree of their airway obstruction as measured by the 1 s forced expiratory volume and maximal midexpiratory flow rate, but their mean response was similar to that in the control subjects. The ventilatory response was then determined with a new index (PM100), which rose linearly with increasing CO2 concentration. Despite wide variation in the slope of PM100 in the patients, their mean response significantly exceeded normal, confirming that the neurochemical drive was increased in bronchial asthma.