[Complex airway resistance as a means of characterizing the strength of asthmatic reaction in the guinea pig].

45 guinea pigs sensitized to ovalbumin and 9 controls were challenged with antigenic aerosol. Before and during the challenge oesophageal pressure (Poes), airflow (V) and tidal volume (VT) were measured in anaesthetized (urethane) spontaneously breathing animals. Inspiratory and expiratory lung resistance (RI, RE) and dynamic lung compliance (Cdyn) were obtained according to the method of Neergard and Wirz. Total pulmonary resistance was calculated by different methods. 18 animals responded with a significant asthmatic reaction with an increase of expiratory resistance and a decrease of dynamic compliance. There exists a close hyperbolic relation between RE and Cdyn before and during the asthmatic reaction. The best parameter to characterize the strength of asthmatic response in the anaesthetized guinea pig is delta Poes/VT.