Anestéziológia a intenzívna medicína 1/2023

Inhomogeneous lung damage − theory of the influence of the time factor on gas exchange in the lungs

In this research report, authors describe time-related factors on gas exchange in non-homogenously affected lungs. Main focus is put on inspiratory time, expiration time in relation to the changing time constants (τ). Using a mathematical model, authors describe the distribution of inhaled gas in a mathematical 5-compartment heterogenous lung model with different properties of each compartment in terms of resistance of compliance. Dependence of respiratory rate on the time constant is also shown with proof that each of the differently affected lung compartments requires a different respiratory rate for optimal filling. In conclusion, in non-homogenously affected lungs, there is also heterogenous distribution of inhaled gas and such distribution is chaotic (while changing over time). As a results, there is therapeutic potential for variable mechanical ventilation to decrease ventilation inequalities and improve aeration.

Keywords: inhomogeneous lung damage, chaotic ventilation, variable ventilation