OPTIMAL RESPIRATORY CONTROL SIMULATION AND COMPARATIVE STUDY OF HYPERCAPNIC VENTILATORY RESPONSES TO EXTERNAL DEAD SPACE LOADING

• Published in: Journal of mechanics in medicine and biology Vol. 14; no. 2; pp. 1450014 - 1-1450014-24
• Main Authors: LIN, SHYAN-LUNG, GUO, NAI-REN, CHEN, TSUNG-CHI
• Format: Journal Article
• Language: English
• Published: Singapore World Scientific Publishing Company 01.04.2014; World Scientific Publishing Co. Pte., Ltd
• Subjects: Carbon dioxide; Comparative studies; Computer simulation; Control simulation; Dyspnea; Human; Inhalation; Mathematical models; Optimization; Organic chemistry; Patients; Predictions; Respiration; Signal monitoring; respiratory control; CO2 inhalation; Ventilatory response; optimality; dead space
• ISSN: 0219-5194; 1793-6810
• DOI: 10.1142/S0219519414500146

There has been considerable research effort regarding ventilatory responses to breathing with an imposed external dead space, and inhalation of fixed levels of CO2 by human subjects. A human respiratory control model incorporating the optimality hypothesis can successfully demonstrate ventilatory responses to both chemical stimuli and muscular exercise. In this study, to verify the model behavior of the optimal chemical–mechanical respiratory control model, we simulated the ventilatory control under dead space loading and CO2 inhalation. The simulation was provided by a LabVIEW® based human respiratory control simulator and signal monitoring system. The dead space measurement was described with two distinct models, derived from Gray and Coon, and predicted behaviors with corresponding ventilatory responses were investigated and compared with experimental findings. While both dead space models produced satisfactory predictions on simulated optimal $\dot{V}_{E}$ versus PaCO2, $\dot{V}_{A}$ versus PaCO2, F versus PICO2, VT versus PICO2, VD-total versus VT, VD-total/VT versus VT, $\dot{V}_{E}$ versus VT and $\dot{V}_{A}$ versus VT relationships, Gray's model provided better correlation and more consistent results throughout most of the ventilatory responses. The study of relative behavior of respiratory signals and comparative relationship of the ventilator responses between dead space loading during rest and CO2 inhalation will certainly provide valuable understanding of increases in central respiratory motor command output of human respiratory control, which is also associated with Dyspnea on exertion, and give potential clinical perspective to realize the impaired ability to excrete CO2 in patients diagnosed with acute respiratory distress syndrome.