Model analysis of steady-state ventilatory response to CO2 into component factors

A method is described to partition measured values of steady-state ventilatory response into an estimation of the blood flow in the respiratory controller and the sensitivity of the controller to CO2 assuming proportional control. The analysis is derived from the describing equations of a computer model and leads to the definition of a grid of lines emanating from a hypothetical reference point at negative ventilation and zero central nervous system metabolism. Data from the literature reporting differences in CO2 response among normal subjects and changes in resting ventilation and cerebral blood flow with age are reinterpreted from this perspective. Use of a structural model to interpret physiological data is shown to give a different meaning to data reduction in contrast to interpretation using statistical models like regression.