Correlation of Blood Pressure Level with Survival and Intraventricular Hemorrhage in Extremely Low Birth Weight Infants during the First Three Days of Life

Abstract

Purpose: Volatile systemic blood pressure and resultant unstable cerebral perfusion are thought to be the major causes of intraventricular hemorrhage (IVH) and death in extremely low birth weight (ELBW) neonates. We examined the immediate postnatal blood pressure level of ELBW infants to correlate blood pressure with neonatal mortality and degree of IVH.Method: This study was performed by retrospective review of medical records of ELBW (＜1000 g) infants admitted to our neonatal intensive care unit (NICU) between 1999 and 2002. Patients with culture-proven perinatal sepsis or major congenital anomalies were excluded. Patients were considered to have hypotension if they received a fluid bolus or vasopressors during the first 72 hours of life to elevate blood pressure.Results: Hypotensive and non-hypotensive infants were similar in birth place, mode of delivery, gender and birth weight. There was a statistical trend of lower gestational age (p=0.05) and lower Apgar score at 1 minute (p=0.07) in the hypotensive group. Infants with lower Apgar scores at 5 minutes (p=0.01) were significantly more likely to have hypotension. There was a significant association between hypotension, grade III-IV IVH (p=0.01) and death (p＜0.01). Using multivariate logistic regression, we found neonatal mortality was the independent factor associated with hypotension.Conclusions: ELBW neonates' blood pressure is often low after birth and increases steadily during the first 72 hours of life. Hypotension in the immediate postnatal period is closely related to neonatal death in ELBW infants. Further studies are needed to understand the underlying mechanisms.