CIRCULATORY CHANGES IN THE DOG PRODUCED BY ACUTE ARTERIOVENOUS FISTULA

Abstract

Acute circulatory changes were studied in 20 dogs after the introduction of an arteriovenous fistula between the right femoral artery and vein. Different anesthetic agents were used and their importance discussed. Studies of the dynamics of circulation indicate that the following changes occur when the fistula is open: (a) there is a reduction of the systolic, diastolic and mean arterial pressure; (b) the heart rate is faster; (c) there is a vasoconstriction in the periphery outside of the fistula circuit and the returning venous flow from these areas is decreased; (d) the central venous pressure remains unchanged; and (e) cardiac output and stroke volume increase. Compensation for the increased flow of blood through the fistula takes place by the increased cardiac output and the decreased flow of blood from areas outside the fistula circuit.