249 Red Cell Volume Determination in Anaemic Fetuses and Newborn Infants Inquiring Transfusion, Using Flow Cytometry: Dilution Principle

Abstract

To evaluate the effects of inotropic suppon on cardiac function and blood pressure in preterm hypotensive infants, we compared 56 preterm infants with respiratory distress syndrome (RDS) (Fi0,>40%) to 27 preterm infants without RDS at 8-72 h of age. In the controls. mean 5 SEM birth weight was 1285+47 g, gestational age 30.95.3 wks, mean blood pressure (MBP) 4551 mm Hg, CO 3192 11 ml/minikg, and systemic vascular resistance (SVR) 132 + 7 mm H a ' / minkg.In the RDS group, these values were 1050+45 g @<0.001). 28.95.4 wks @=0.002). 3621 mm Hg @<0.001). 358515 ml/min/kg, and 10728 mm HgE1/min/kg. 26 (46%) RDS infants received dopamine, in 12 (21%) combined with dobutamine, and 29% had a MBP 530 mm Hg. CO in hypotensive and normotensive RDS infants was similar. In the RDS group, MBP was 37+3 mm Hg and SVR 243251 mm Hg/L"/min/kg in the low CO @50 mVminkg) subgroup and 32+2 mm Hg and 5 2 9 mm HgK1/minkg in the high CO k 4 1 0 mVmin/kg) subgroup (p<0.001 vs controls). Treatment of RDS infants with dopamine or dopamine + dobutamine raised MBP to values similar to those not receiving inotropic support but addition of dobutamine significantly increased CO and reduced SVR. These data indicate that whereas dopamine mainly affects blood pressure, dobutamine added onto dopamine simultaneously increases CO, leading to a reduction in SVR. In f e t u s e s with Rh haemolytic disease and i n anaemic i n f a n t s helps ~s e s s m e n t of Tx need and allows blood volume c a l c u l a t i o n . Neonates' CV can be measured a t Tx using d l l u t i o n of autologous HbF by donor d u l t Hb, provided a t l e a s t 20% of the Hb is f e t a l . W e report an nalogous method, using 0 . 1 m l blood samples, based on FACSetermined f a l l s i n RhD positive c e l l s a t Tx with D negatlve e l l s . E he methods give comparable r e s u l t s (Neither the ranked pair l f f e r e n c e s nor t h ? medlan of the two samples were s i g n i f~c a n t l y i f f e r e n t ; "=lo, p (0.05).0ur new method is r e l l a b l e a f t e r smallerolume Tx than possible using the Hb F d l l u t l o n method. Thls nvestigatlon i s placing Tx schedules i n these patlents o n a more a t i o n a l b a s l s than previously possible. Aleid G. van Wassenaer*,**, Joke H. Kok*, Jan J . M . de Vijlder** Departments of *neonatology and **experimental p e d i a t r i c endocrinolog y , Academic Medical Centre, Amsterdam, The Netherlands. BACKGROUND: Transient hypothyroxinemia i 6 a very frequent occurring phenomenon i n very pretenn infants. Low T4 l e v e l s a r e r e l a t e d t o poor developmental outcome. However, T4 treatment i n very pretenn i n f a n t e i s s t i l l controversial. Aln: To improve developmental outcome a t 24 months. Preliminary analysis of c l i n i c a l outcome is now presented. KETHODS: 193 i n f a n t s <30 wks GA were randomly assigned t o T4(T)-o r placebo(P) treatment, which was s t a r t e d 12-24 h r s a f t e r b i r t h i n a dosage of 8 pg/kg birthweightlday during t h e f i r s t 6 weeks a f t e r b i r t h . RESULTS: The...