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Changes in the hemodynamics of the brain and the growth of the child
Last reviewed: 23.04.2024
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Changes in the hemodynamics of the brain associated with the growth and development of the child
The indices of cerebral blood flow of a healthy newborn are determined, first of all, by gestational age and by the presence (or absence) of a hemodynamically significant functioning arterial duct. Persistence of the latter is accompanied by a discharge of blood into the small circle of blood circulation with depletion of blood flow in the vessels of the brain, which is characterized by a low diastolic rate, and sometimes a change in systolic velocity. Normally, with an increase in gestational, postnatal age and weight during the first months of life, gradual increase in LSC scores, a decrease in PI and MI in the arteries, and an increase in average speed in large venous reservoirs are noted. The greatest changes occur on the first 2-4 days of life, which is associated with the closure of fetal communications and a gradual decrease in the resistance of cerebral vessels.
Indices of blood flow through the intracranial arteries, obtained on the basis of a dynamic study of newborns at 1-7 days of life in uncomplicated early neonatal period in term donors and "conditionally healthy" premature infants, depending on the gestational age, did not reveal any significant differences and may be taken for the norm.
However, when interpreting the dopplerography of cerebral vascular vessels, it is necessary to take into account not only the weight, gestational and postnatal age of the child, but also the influence of such factors as hematocrit, partial pressure of oxygen and carbon dioxide, blood glucose concentration, and circulating blood volume. The hemodynamically significant open arterial duct leads to left-right shunting of the blood and impoverishment of the flow to the head, which is expressed in a sharp decrease in diastolic velocity (sometimes even retrograde casting during diastole) and high IR values.
With age, an increase in the linear velocity of blood flow through the veins and sinuses of the brain is noted.
When qualitatively evaluating the nature of the Doppler, it is necessary to pay attention to its monophasic spectrum in the Galen vein and thalamo-striatal vein and the presence of pulsations (pseudoarterial nature) in the brain sinuses. The pseudoarterial nature of the blood flow in the Venus Galena may indicate the presence of signs of venous dyscirculation, which subsequently leads children with perinatal encephalopathy to development at the age of 3-4 months of life of hypertensive hydrocephalic syndrome.
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