Changes in cardiac function and cerebral blood flow in relation to peri/intraventricular hemorrhage in extremely preterm infants

Abstract

Objective: To investigate whether changes in cardiac function and cerebral blood flow (CBF) precede the occurrence of peri/intraventricular hemorrhage (P/IVH) in extremely preterm infants.

Study design: In this prospective observational study, 22 preterm infants (gestational age 25.9 ± 1.2 weeks; range 23-27 weeks) were monitored between 4 and 76 hours after birth. Cardiac function and changes in CBF and P/IVH were assessed by ultrasound every 12 hours. Changes in CBF were also followed by continuous monitoring of cerebral regional oxygen saturation (rSO2) and by calculating cerebral fractional oxygen extraction.

Results: Five patients developed P/IVH (1 patient grade II and 4 patients grade IV). Whereas measures of cardiac function and CBF remained unchanged in neonates without P/IVH, patients with P/IVH tended to have lower left ventricular output and had lower left ventricle stroke volume and cerebral rSO2 and higher cerebral fractional oxygen extraction during the first 12 hours of the study. By 28 hours, these variables were similar in the 2 groups and myocardial performance index was lower and middle cerebral artery mean flow velocity higher in the P/IVH group. P/IVH was detected after these changes occurred.

Conclusions: Cardiac function and CBF remain stable in very preterm neonates who do not develop P/IVH during the first 3 postnatal days. In very preterm neonates developing P/IVH during this period, lower systemic perfusion and CBF followed by an increase in these variables precede the development of P/IVH. Monitoring cardiac function and cerebral rSO2 may identify infants at higher risk for developing P/IVH before the bleeding occurs.

Keywords: Arterial oxygen saturation; CBF; CFOE; CO(2); Carbon dioxide; Cerebral blood flow; Cerebral fractional oxygen extraction; Heart rate-corrected velocity of circumferential fiber shortening; LVO; Left ventricular output; MCA; MCA mean velocity; MCA-MV; MPI; Middle cerebral artery; Myocardial performance index; NIRS; Near-infrared spectroscopy; P/IVH; PDA; Patent ductus arteriosus; Peri/intraventricular hemorrhage; RVO; Regional oxygen saturation; Right ventricular output; SVR; SpO(2); Systemic vascular resistance; US; Ultrasound; VCF(C); rSO(2).