Effects of varying hematocrit on intestinal oxygen uptake in neonatal lambs

Journal Article · Mon Apr 01 00:00:00 EST 1985 · Am. J. Physiol.; (United States)

OSTI ID:5609501

Holzman, I R; Tabata, B; Edelstone, D I

The authors chronically catheterized 15 newborn lambs (9.5 +/- 2.8 days) and measured intestinal blood flow (Qi) by the radionuclide microsphere technique at hematocrit levels ranging from 10 to 55%. Seven animals were made progressively anemic and eight polycythemic by means of exchange transfusions. Using the Fick principle, they calculated intestinal oxygen delivery (Di O/sub 2/), oxygen consumption (Vi O/sub 2/), and oxygen extraction. Initial base-line values were Qi = 195.5 ml . min-1 . 100 g intestine-1, Di O/sub 2/ = 22.1 ml . min-1 . 100 g-1, Vi O/sub 2/ = 4.8 ml . min-1 . 100 g-1, and O/sub 2/ extraction = 22.5%. As the hematocrit was lowered, Di O/sub 2/ decreased and O2 extraction increased and vice versa when the hematocrit was raised. Vi O/sub 2/ remained constant, but Qi did not correlate with changes in hematocrit. However, intestinal blood flow, as a percent distribution of total blood flow, decreased with lower hematocrit levels. At no time was there any evidence of anaerobic metabolism as measured by excess lactate production. The data indicate that the intestines of neonatal lambs are capable of maintaining their metabolic needs over a wide range of oxygen availability induced by a changing hematocrit. The primary mechanism is through alteration of oxygen extraction. Within the range of the experiments, no critically low oxygen availability was attained at which anaerobic metabolism became significant.

• Research Organization: Univ. of Pittsburgh School of Medicine, PA
• OSTI ID: 5609501
• Journal Information: Am. J. Physiol.; (United States), Vol. 248
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
INTESTINES
BLOOD FLOW
OXYGEN
UPTAKE
ANEMIAS
DYNAMIC FUNCTION STUDIES
METABOLISM
NEONATES
RADIOISOTOPES
SHEEP
ANIMALS
BODY
DIGESTIVE SYSTEM
DISEASES
DOMESTIC ANIMALS
ELEMENTS
GASTROINTESTINAL TRACT
HEMIC DISEASES
ISOTOPES
MAMMALS
NONMETALS
ORGANS
RUMINANTS
SYMPTOMS
VERTEBRATES
551001* - Physiological Systems- Tracer Techniques