Abstract
ABSTRACT: Blood viscosity is an important determinant of blood flow resistance. Because a substantial part of flow resistance arises in small arteries and arterioles with diameters of 100 μm and less, rheologic properties of blood from preterm infants (24 to 36 wk of gestation), full-term neonates, and adults were measured in glass tubes with diameters of 50, 100, and 500 μm for a wide range of adjusted feed hematocrits (0.15–0.70). At each of the feed hematocrits, blood viscosity decreased when going from a 500–μm tube to a 50–μm tube. The viscosity reduction increased with increasing hematocrit. Moreover, the viscosity reduction was more pronounced in the neonates than in the adults. At a hematocrit of 0.70, the viscosity reduction averaged 56% in preterm infants, 50% in full-term neonates, and 39% in adults (p < 0.005). However, the viscosity reductions at a hematocrit of 0.30 were only 35, 29, and 19%, respectively (p < 0.05). In all four groups, blood viscosity increased exponentially with increasing hematocrit. The steepness of the hematocrit-viscosity curves decreased with decreasing tube diameter and with decreasing maturity of the infants. Erythrocyte transport efficiency (hematocrit/blood viscosity) was calculated to estimate the optimal hematocrit (i.e. hematocrit with maximum erythrocyte transport). In 500-Ann tubes, the optimal hematocrit was about 0.40 in all of the groups. In 100–μm tubes, the optimal hematocrit was 0.44 ± 0.05 in the adults and 0.52 ± 0.04 in the neonates (p < 0.05). In 50–μm tubes, the optimal hematocrit was 0.51 ± 0.04 in adults and 0.60 ± 0.05 in the neonates. There was no significant difference in the optimal hematocrit among preterm and full-term infants. Our results suggest that the strong viscosity reduction at high hematocrits may help to maintain oxygen transport in polycythemic neonates.
Similar content being viewed by others
Article PDF
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Linderkamp, O., Stadler, A. & Zilow, E. Blood Viscosity and Optimal Hematocrit in Preterm and Full-Term Neonates in 50– to 500–μm Tubes. Pediatr Res 32, 97–102 (1992). https://doi.org/10.1203/00006450-199207000-00019
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1203/00006450-199207000-00019
This article is cited by
-
Early versus delayed umbilical cord clamping in infants with congenital heart disease: a pilot, randomized, controlled trial
Journal of Perinatology (2015)
-
Oxidative stress markers and micronutrients in maternal and cord blood in relation to neonatal outcome
European Journal of Clinical Nutrition (2014)
-
Whole-blood viscosity in the neonate: effects of gestational age, hematocrit, mean corpuscular volume and umbilical cord milking
Journal of Perinatology (2014)
-
Effects of Intralipid infusion on hemorheology and peripheral resistance in neonates and children
Pediatric Surgery International (2005)