Objectives: To develop a model for the calculation of pulmonary blood flow (Q̇p) and blood flow through intrapulmonary arteriovenous anastomoses (Q̇IPAVA) 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 noninvasive measures of cardiac output (Q̇t) in young and healthy men.
Results: It was possible to precisely calculate Q̇p and Q̇IPAVA 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 under heavy exercise, Q̇p decreased slightly (97.56% of Q̇t), and Q̇IPAVA represented 2.44% of Q̇t.
Instead, in hypoxia at heavy exercise, Q̇p decreased significantly (85.25% of Q̇t), and Q̇IPAVA increased significantly (14.75% of Q̇t), equal to Q̇IPAVA of 3.48 L/min.
It was possible to demonstrate a negative contribution of Q̇IPAVA directly to pulmonary gas exchange efficiency.
Furthermore, the model immediately identifies incorrect Q̇t measurements.
Conclusions: This new mathematical model is precise in calculating Q̇p and Q̇IPAVA.
The required data are obtained through noninvasive instruments, which are easy to use and widespread in all hospitals. Q̇p differs significantly from Q̇t 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.