Chapter 18 - Cerebral haemodynamics in the human newborn studied by electrical impedance - methodology

Abstract

Publisher Summary This chapter discusses the cerebral hemodynamics in the human newborn studied by electrical impedance. The development of a safe method to study the cerebral circulation in the newborn remains a priority, especially in the investigation of the causes of periventricular hemorrhage in the preterm infant. It is apparent that changes in volume will produce changes in electrical impedance. Thus the changes in blood volume which occur within the head during each cardiac cycle will give rise to cardiac-synchronous changes superimposed on the basal component of cerebral electrical impedance. The variations in resistivity will also contribute to changes in electrical impedance. This combined with the complex fluid dynamics of the head in the newborn means that the cardiac-synchronous pulsatile impedance component is multifactorial in its origins. It is shown that an index of cerebral blood flow derived from the cardiac-synchronous changes signal shows a significant correlation with the estimates of cerebral blood flow (CBF) given by the method of strain-gauge venous occlusion plethysmography. Signal shows a significant correlation with the estimates of CBF given by the method of strain-gauge venous occlusion plethysmography.