Evaluation of the microsphere-method for determination of cardiac output.
Cardiac output was determined by means of radioactive microspheres, 15 +/- 5 microns in diameter. Blood flow in the ascending aorta was measured by an electromagnetic flowmeter. In eight cats thirty-eight simultaneous measurements were made of cardiac output and aortic flow. The observations correlated well (r = 0.89), with a mean difference of 5.2%, probably corresponding to coronary blood flow. Continuous flow recordings showed no alterations in aortic flow during the injections of microspheres; arterial blood pressure and heart rate remained unchanged even after six injections, each consisting of about 2 x 10(5) spheres per kg body weight. Tests for shunting of microspheres were performed and revealed shunt fractions in the systemic circulation of about 8%, with no significant shunting through the lungs. The microsphere method for determining cardiac output is thought to be an accurate method, suitable for small and medium sized animals.
D000818:Animals; D001011:Aorta / Q000502:physiology; D002302:Cardiac Output; D002415:Cats; D002588:Cesium Radioisotopes; D005260:Female; D008297:Male; D008863:Microspheres; D012039:Regional Blood Flow; D012212:Rheology; D013326:Strontium Radioisotopes
D002588:Cesium Radioisotopes; D013326:Strontium Radioisotopes