title: Assessment of responsiveness to carbon dioxide in patients with chronic airways obstruction by rate of isometric inspiratory pressure development.
abstract: 1. Responsiveness to CO2 was measured in forty patients with chronic airways obstruction in terms of ventilation and rate of isometric inspiratory pressure change [(dP/dt)max]. 2. The ventilatory response was below the normal range in eighteen out of twenty-two patients with normal arterial CO2 tensions and in all of eighteen patients with CO2 retention. 2. The (dP/dt)max. response was distributed throughout the normal range in all but one of the patients with normal arterial CO2 tension. In all the patients with CO2 retention the (dP/dt)max. response was either at or below the lower limit of the normal range. 4. Although the ventilatory responses correlated significantly with FEV1 there was no such correlation for the (dP/dt)max. responses. 5. The (dP/dt)max. response showed a significant negative correlation with Pa,CO2. 6. It is believed that the (dP/dt)max. response to CO2 can be used to assess central CO2 responsiveness in subjects with airways obstruction independently of mechanical factors limiting their ventilation.
mesh_terms: D000368:Aged; D000402:Airway Obstruction / Q000175:diagnosis / Q000503:physiopathology*; D002245:Carbon Dioxide; D002648:Child; D006801:Humans; D006935:Hypercapnia / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D010313:Partial Pressure; D012119:Respiration
chemical_list: D002245:Carbon Dioxide