644 Red Cell Sequestration in Preterm Infants

Abstract

P e d i a t r i c s . SUNP. U p s t a t e MedicalCenter. Syracuse. New York. h e p o l y o l o r s o r b i t o l pathway h u , been demonstrated i n human e r y t h r o c y t e s and s c c o u n t s f o r 2 t o 3 p e r c e n t o f g l u c o s e metabolism a t p h y s i o l o g i c g l u c o s e c o n c e n t r a t i o a e . The flow through t h i s pathway is r e g u l a t e d by t h e d i e n t g l u c o s e c o n c a t r a t i o n . A t h i g h g l u c o s e c o n c e n t r a t i o n s , t h e a c c u m~h t i o n o f s o r b i t o l and f r u c t o s e is a s s o c i a t e d w i t h a decreased concen-t r a t i o n of p y r w a t e , i n c r e a s e i n t h e l a c t a t e / p y r u v a t e r a t i o and a c c u r m l a t i o n of t h e t r i o s e phosphates.These changes a r e f e l t t o r e f l e c t a l t e r a t i o n s i n t h e NADINADH r a t i o . To d i r e c t l y tut t h i s h y p o t h e s i s r e d c e l l s f r m 12 normal a d u l t s a n d 1 2 newborn i n f a n t s were i n c u b a t e d a t 5 and 50 . 1 1 g l u c o s e f o r p e r i o d s o f 3 h o u r s and NAD and NALM c o n c e n t r a t i o n # were determined by t h e method o f S a n d e r e t a 1 (Anal. B i o c h e~. , 71:29, 1976) i n conj u n c t i o n w i t h measurements o f l a c t a t e and p y n n a t e . At 0 t h e NADINADH r a t i o s a v e r a g e d 5.9 in the a d u l t s and 6.8 i n the newborns.A f t e r 3 h o u r s o f i n c u b a t i o n the W / W r a t i o s rose to 11.2 and 16.0 r e s p e c t i v e l y a t 5 mM g l u c o s e b u t w e r e 24.7 and 47.2 a t t h e 50 d l g l u c o s e c o n c e n t r a t i o n . Changes i n NADINADH r a t i o s p a r a l l e l e d changes in t h e p y m v a t e t o l a c t a t e r a t i o s . These o b s e r v a t i o n s v a l i d a t e t h e u s e o f t h e l a c t a t e / p y r w a t e r a t i o a s an i n d i r e c t l e u u r e of the NAD/NADii r a t i o and demons t r a t e t h e e f f e c t s of g l u c o s e c o n c e n t r a t i o n on the r e d o x p o t e n t i a l o f t h e c e l l a r d i a t e d v i a t h e .orbit01 pathvay. RED CELL SEQUESTRATION IN PRETERM INFANTS. C h a r l e s L644 Paxson, Jr., Jav W. Dirksen, Merton A. Quaife. UNMC Omaha, Neb. (spon. by G.C. Rosenquist) No p r e v i o u s s t u d i e s have e v a l u a t e d t h e r e s p o n s e of r e d c e l l volume (RCV) t o blood t r a n s f u s i o n (Tx) i n h y p o t e n s i v e p r e t e r m i n f a n t s . We measured RCV i n 69 h y p o t e n s i v e i n f a n t s w i t h r e s p i ra t o r y d i s t r e s s syndrome (RDS) u s i n g Tc-99m and 51 Cr r e d c e l l l e v e l i n g .A l l p a t i e n t s r e c e i v e d Tx i n amounts e s t i m a t e d by i n it i a l RCV t o b e s u f f i c i e n t t o r e s t o r e t h e volume t o normal (55-60 mllkg).Following Tx, RCVs were r e p e a t e d i n 27 p a t i e n t s ; 2-7 s e r i a l v a l u e s were o b t a i n e d .S i x t y -f i v e i n f a n t s responded t o Tx w i t h a r i s e i n blood press u r e (BP) a n d l o r RCV; 4 had no r i s e i n RCV ( 3 e x p...