The Effect of Added Dead Space on Optimal Neuro-Muscular Drive and Respiratory Signals under Hypercapnia

Abstract

The problem concerning the nature and the function of the dead space is of basic importance for the fullcomprehension of the respiratory physiology and pathophysiology. To study the effect of an imposed external deadspace on the optimal respiratory control system, we simulated the optimal neuro-muscular drive and respiratorysignals, including instantaneous airflow and lung volume profiles, with dead space loading under hypercapnia. Thedead space measurement model by Gray was employed and the human respiratory control simulator based on anoptimality hypothesis was implemented. The ventilatory control simulations were performed with external dead spaceloading of 0, 0.4 and 0.8 liters under rest condition (PICO2=0%) and CO2 inhalation of 3% to 7%. The optimization ofthe respiratory signals and model behavior of the optimal respiratory control under dead space loading andhypercapnia were verified and found to be in general agreement with experimental findings.