Numerical estimation of optimal limits of cerebral blood flow and oxygen partial pressure in brain tissue of preterm infants

Abstract

Background and Objective: For normal brain function, a sufficient supply of oxygen to resident cells is essential. A lack of oxygen delivery can cause irreversible neuronal damage within minutes. This situation is especially critical for preterm infants and can lead to lifelong mental and motor disabilities. Although cerebral blood flow (CBF) and tissue partial pressure of oxygen (PtO₂) provide important information on oxygen delivery and consumption in the brain, appropriate clinically suitable measuring techniques are still lacking. Methods: Mathematical modeling of cerebral oxygen transport is a promising complementary approach for the assessment of PtO₂ in the brain tissue of newborns. A nonlinear model of oxygen transport from capillaries to tissue was coupled with the cerebrovascular model for CBF calculation in preterm infants. The advantage of this mathematical method lies in its ability to estimate CBF and PtO₂ from routinely measured parameters such as mean arterial blood pressure, hematocrit, arterial carbon dioxide and oxygen partial pressure. Results: The combined model was applied to estimate optimal limits of CBF and PtO₂ in the brain tissue of preterm infants with gestational ages between 23 and 32 weeks of pregnancy using optimal values of medical parameters from clinical routine. Conclusions: The calculated optimal values can be used as additional parameters to assess the health condition of patients during the neonatal period.