Microsphere estimates of blood flow: Methodological considerations

Journal Article · Mon Feb 01 04:00:00 EST 1988 · American Journal of Physiology; (USA)

OSTI ID:6868108

von Ritter, C; Hinder, R A; Womack, W; Bauerfeind, P; Fimmel, C J; Kvietys, P R; Granger, D N; Blum, A L ^[1]

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1. Univ. of the Witwatersrand, Johannesburg (South Africa) Louisianna State Univ. Medical Center, Shreveport (USA) Universitaire Vaudois (Switzerland)

The microsphere technique is a standard method for measuring blood flow in experimental animals. Sporadic reports have appeared outlining the limitations of this method. In this study the authors have systematically assessed the effect of blood withdrawals for reference sampling, microsphere numbers, and anesthesia on blood flow estimates using radioactive microspheres in dogs. Experiments were performed on 18 conscious and 12 anesthetized dogs. Four blood flow estimates were performed over 120 min using 1 {times} 10{sup 6} microspheres each time. The effects of excessive numbers of microspheres pentobarbital sodium anesthesia, and replacement of volume loss for reference samples with dextran 70 were assessed. In both conscious and anesthetized dogs a progressive decrease in gastric mucosal blood flow and cardiac output was observed over 120 min. This was also observed in the pancreas in conscious dogs. The major factor responsible for these changes was the volume loss due to the reference sample withdrawals. Replacement of the withdrawn blood with dextran 70 led to stable blood flows to all organs. The injection of excessive numbers of microspheres did not modify hemodynamics to a greater extent than did the injection of 4 million microspheres. Anesthesia exerted no influence on blood flow other than raising coronary flow. The authors conclude that although blood flow to the gastric mucosa and the pancreas is sensitive to the minor hemodynamic changes associated with the microsphere technique, replacement of volume loss for reference samples ensures stable blood flow to all organs over a 120-min period.

• OSTI ID: 6868108
• Journal Information: American Journal of Physiology; (USA), Journal Name: American Journal of Physiology; (USA) Vol. 254:2; ISSN 0002-9513; ISSN AJPHA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
ALKALI METAL ISOTOPES
ANESTHESIA
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
BLOOD FLOW
BODY
CARDIOVASCULAR SYSTEM
CERIUM 141
CERIUM ISOTOPES
CHROMIUM 51
CHROMIUM ISOTOPES
DAYS LIVING RADIOISOTOPES
DOGS
DYNAMIC FUNCTION STUDIES
ELECTROMAGNETIC RADIATION
ELECTRON CAPTURE RADIOISOTOPES
EVEN-ODD NUCLEI
GAMMA RADIATION
HEART
INTERMEDIATE MASS NUCLEI
INTERNAL CONVERSION RADIOISOTOPES
IONIZING RADIATIONS
ISOMERIC TRANSITION ISOTOPES
ISOTOPES
MAMMALS
MEMBRANES
MICROSPHERES
MUCOUS MEMBRANES
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
ORGANS
RADIATIONS
RADIOASSAY
RADIOISOTOPES
RARE EARTH ISOTOPES
RARE EARTH NUCLEI
RUBIDIUM 103
RUBIDIUM ISOTOPES
SCANDIUM 46
SCANDIUM ISOTOPES
SECONDS LIVING RADIOISO
VERTEBRATES
VOLUME