991 Capillary Venous Hematocrit Difference in Newborn Infants: Relation to Blood Volume, Peripheral Blood Flow, and Acid Base Status

Abstract

The metabolic responses t o a c o n s t a n t glucose i n f u s i o n (4.3% .2 mglkglrnin) were measured i n 30 prematures, 700-15598. The s t u d y included 1 8 s t r e s s e d i n f a n t s who needed a s s i s t e d v e n t i l at i o n (Grp A) and 12 c o n t r o l s (Grp B). Plasma samples f o r gluc o s e , i n s u l i n , c o r t i s o l , and g l y c e r o l were obtained from cord blood, j u s t p r i o r t o glucose i n f u s i o n a t 2.1+.2 h r (mean + S.E.)

Red Cell Volume Can Be Accurately Determined in Sheep Using a Nonradioactive Biotin Label

“…Second, ex vivo use of 125 I, an intermediate-lived isotope is avoided. Third, the biotin flow cytometric enumeration method is not susceptible to artifacts arising from either dilution (“squeezing”) or concentration (“sludging”) in obtaining venous/capillary blood samples after infusing the labeled RBCs (13, 14) because flow cytometric enumeration depends upon labeled RBCs as a percent of total RBCs rather than as a concentration of label in the blood sample. In contrast, the biotin method using the ( 125 I)streptavidin technique measures the blood concentration of the RBC label and, thus, is analogous to determination of RCV by 51 Cr, 99m Tc, and ( 14 C)cyanate.…”

“…This technique determines labeled RBCs as a percent of total cells rather than as the blood concentration of the biotin label. The flow cytometry technique offers the advantage over the ( 125 I)streptavidin technique and the 51 Cr and ( 14 C)cyanate methods of not being susceptible to concentration (“sludging”) and dilution (“squeezing”) blood sample artifacts encountered with capillary blood sampling frequently performed in newborns (13, 14). …”

Peripheral circulation in the newborn: Interaction of peripheral blood flow, blood pressure, blood volume, and blood viscosity

“…Air-filled [21,31,33,35,36,38,39], water-filled [2, 3, 7--10] and mercury-in-rubber strain-gauge plethysmographs [1,4,11,19,28] have been applied. Mercury-in-rubber strain gauges measure the change in volume of only a small segment of the limb.…”

“…B l o o d viscosity a p p a r e n t l y does n o t influence p e r i p h e r a l c i r c u l a t i o n in the n e w b o r n [3]. I n d i r e c t e v i d e n c e for a r e l a t i o n b e t w e e n p e r i p h e r a l b l o o d f l o w a n d m i c r o c i r c u l a t i o n was p r o v i d e d by the d e m o n s t r a t i o n o f an inverse r e l a t i o n s h i p b e t w e e n the c a p i l l a r y / v e n o u s h a e m a t o c r i t r a t i o a n d p e r i p h e r a l b l o o d f l o w in n e w b o r n infants [28]. T h e i n t e r r e l a t i o n s h i p s b e t w e e n peripheral S i m u l t a n e o u s m e a s u r e m e n t s o f these c i r c u l a t o r y p a r a m e t e r s in newb o r n infants h a v e n o t b e e n r e p o r t e d .…”

Association of neonatal respiratory distress with birth asphyxia and deficiency of red cell mass in premature infants

“…Hypovolaemia, probably one major side effect of intra-partum asphyxia, causes marked reduction of cardiac output [26] and of peripheral blood flow [18,35] in the newborn. Hypoxia may further reduce cardiac output [26] and disturb the microcirculation [20], and this is probably mediated by catecholamines [21]. Hypovolaemia is followed by plasma expansion [35], which means a decreasing oxygen capacity.…”