Effects of Pressure- And Volume-controlled Ventilation on Pulmonary Ventilation and Gas Exchange in Obstructive Lung Disease: A Comparative Study

Chronic obstructive pulmonary disease (COPD) is one of the leading causes of death in the world. Its pathophysiological hallmark is expiratory flow limitation. But it's unclear whether pressure-controlled ventilation (PCV) or volume-controlled ventilation (VCV) has a lower risk of barotrauma and which one can provide more adequate gas exchange for the patients. In this study, the effects of PCV and VCV on pulmonary ventilation and gas exchange were compared for COPD patients with expiratory flow limitation by modeling the pulmonary ventilation and the gas exchange during mechanical ventilation. It is found the peak transpulmonary pressure was similar between PCV and VCV, indicating the two modes may have similar risk of barotrauma. The transmural pressure of collapsible airways increased more rapidly at the beginning of inspiration in PCV than in VCV. And the partial pressures of oxygen and carbon dioxide were similar between PCV and VCV. The results suggest that the two modes seem to be equally suited for COPD patients with expiratory flow limitation. But PCV may open collapsed airways earlier.