EFFECT OF HIGH AMBIENT PRESSURE AND OXYGEN-TENSION ON ORGAN BLOOD-FLOW IN THE ANESTHETIZED RAT

  • 1 January 1980
    • journal article
    • research article
    • Vol. 7  (1) , 47-60
Abstract
Cardiac output [CO] and blood flow to major organs were investigated in pentobarbital-anesthetized rats using 85Sr- and 141Ce-labeled microspheres (MS) (15 .+-. 1 .mu.m (SD) injected into the left ventricle. Since MS dissolved in dextran cannot be used in albino rats, the method was evaluated using MS dissolved in Ficoll-70. Two subsequent MS injections were administered to each rat at normal gas atm and atmospheric pressure (Group 1). Homogeneous mixing of MS dissolved in Ficoll-70 and good reproducibility of hemodynamic measurements was demonstrated using ventricular injection. In 3 other series, control measurements were performed in each rat at a normal gas atm and at atmospheric pressure, and in 1 of the following situations: at 5.0 atm absolute (ATA) of ambient pressure and normal O2 tension (PO2 = 0.2 ATA) (Group 2); at an ambient pressure of 5 ATA and high O2 tension (PO2 = 1.0 ATA) (Group 3); and at normal ambient pressure and high O2 tension (PO2 = 1.0 ATA) (Group 4). The inert gas was N2. Cardiac output, heart rate and mean arterial pressure did not change in any group. Renal blood flow fell by 15% (P < 0.05) in all groups except in Group 1. Myocardial and cerebral blood flow increased by 30% (P < 0.05) in groups 2 and 3. Blood flow in the diaphragm fell by 40% (P < 0.001) in Group 4.