A Mathematical Model for Quantification of Pulmonary and Intrapulmonary Arteriovenous Anastomoses Blood Flow

Abstract

Objectives: To develop a model for the calculation of pulmonary blood flow (Qp) and blood flow through intrapulmonary arteriovenous anastomoses (QIPAVA) under multiple physiological conditions. Methods: A mathematical model was developed into which many experimental physiological parameters were input. Data were obtained simultaneously from arterial blood gases, metabolic measures, and non-invasive measures of cardiac output (Qt) , in young and healthy men. Results: It was possible to precisely calculate Qp and QIPAVA at rest, and at moderate (50% of VO2max ) and heavy exercise ( 90% of VO2max ), in both normoxia (FIO2= 0.2093) and acute hypoxia (FIO2 = 0.125). In normoxia at heavy exercise, Qp decreased slightly (97.56% of Qt) and QIPAVA represented 2.44% of Qt . Instead in hypoxia at heavy exercise, Qp decreased significantly (85.25% of Qt) and QIPAVA increased significantly (14.75% of Qt), equal to QIPAVA of 3.48 L/min. It was possible to demonstrate a negative contribution of QIPAVA directly on pulmonary gas exchange efficiency. Furthermore, the model immediately identifies incorrect Qt measurements. Conclusions: This new mathematical model is precise in calculating Qp and QIPAVA. The required data are obtained through non-invasive instruments, easy to use and widespread in all hospitals. Qp differs significantly from Qt under some physiological conditions. The application of this model in the medical field is expected to enable further advancements in scientific research and clinical practice.