Modeling rapidly adapting pulmonary stretch receptor activity to step-wise and constant pressure inflation of the lungs.

Rapidly-adapting pulmonary stretch receptors (RAPSRs) provide the central nervous system with information regarding the rate of lung inflation, lung compliance and the sensation of dyspnea. Other than satisfying parameters of an adaptation index to constant pressure lung inflation for identification, no mathematical model has been ascribed to the stimulus-response relationship of lung volume-pressure to RAPSR activity. Herein, linear, power, polynomial and non-linear (four parameters logistic) models are tested for the best "goodness of fit" line of RAPSR activity to step-wise lung inflation to four times tidal volume and constant pressure inflation to 10, 20, 30 and 40 cm H2O of the lungs of guinea pigs and dogs. Goodness of fit was determined by evaluating coefficient of determination (R2) and visual inspection. The best "goodness of fit" is one of a non-linear symmetrical, stimulus-response function.