[Study of the respiratory profile in symptomatic asthma patients]

The following indexes were measured in 10 normal volunteers and 25 symptomatic asthmatic patients: --tidal volume (VT), breathing frequency (f), minute ventilation (Ve); --forced expiratory volume in 1 s. (FEV1), vital capacity (VC), residual volume (RV) and partial pressure of 02-C02 in arterial blood (Pa02-C02); --mean inspiratory flow (VT/Ti); --inspiratory duty cycle (Ti/Tt). Our data suggest a "ventilatory pattern" of the asthmatic patients may be characterized by the following features: --increasing of tidal volume (VT) and minute ventilation (Ve); --increasing of the mean inspiratory flow (Vt/Ti); --reduction of inspiratory duty cycle (Ti/Tt). This suggest that the breathing pattern may help to differentiate symptomatic asthmatic patients form patients with chronic obstructive pulmonary disease who have similar degrees of pulmonary hyperinflation, but breathe with faster rates and slightly elevated tidal volumes.