82 A Low Mean Blood Pressure in Extremely Low Birth Weight Infants in the First Week is not a Risk Factor for Neurodevelopmental Problems at Age 2 Years

Abstract

Background: Hypotension may cause poor perfusion and ischaemia. It is not known what BP is too low to maintain adequate tissue perfusion. We have previously measured the distribution of BP in a database of 1230 infants (238 <1000g) over the first week of life. We examined whether a low mean blood pressure (mBP) in extremely low birth weight (ELBW), (<1000g) was associated with later abnormal neurodevelopment.Methods: From 9/1997 to 10/2002, all ELBW infants were included who had continuous intravascular BP measurements. For each infant, each 6 hr period over the first 7 days of life was given a z score related to the total population. Small for gestational age (SGA) infants (n=32) and infants with >50% missing data (n=23) were excluded. The neurodevelopment (motor and communication skills, hearing, vision and overall development) of surviving infants was scored at two years corrected age - normal 1, mild problems 2, moderate 3, severe 4, dead 5. Severity of disability was plotted against the mBP Z-score and the Kruskal-Wallis test was used to compare groups.Results: Data were available for 62 infants - gestation 25.2 weeks (SD 1.30) birthweight 756g (SD 140), 37 were male, 36 received inotropes. 18 died, and 4 were lost to follow up. At 2 year follow up, 15 (38%) had developmental delay, 9 (23%) motor and 17 (43%)communication difficulties, 11 (28%) visual and 2 (5%) hearing problems. There was no significant relationship between the mBP in the first week and the presence or degree of any neurodevelopmental parameter at the age of 2 years.Conclusion: In this series we could define no relationship between mBP in the first week of life and neurodevelopmental outcome at 2 years of age.