THE EFFECTS of six sympathomimetic drugs upon the cardiac output and blood flow to the hind limbs of dogs have been studied in a model designed to simulate operative or immediate postoperative conditions of slight hypotension without major blood volume deficiency. Decrease in blood pressure in spite of blood volume maintenance may cause concern that blood flow to vital organs is inadequate or that thrombosis may occur following arterial reconstruction. A pharmacologic agent which would reliably increase both blood pressure and blood flow would be useful in these circumstances.
Although blood pressure is a widely used measurement of circulatory status, pressure and flow are not necessarily related, as blood pressure varies with both cardiac output and vascular resistance.1 The principle of "hemometakinesia" also indicates that regional blood flow and vascular resistance may change even though cardiac output and blood pressure remain constant.2 Accordingly, drugs which alter blood pressure
Skinner DB, Camp TF, Austen WG. Use of Vasopressor Agents to Increase Somatic Blood Flow. Arch Surg. 1967;94(5):610-618. doi:10.1001/archsurg.1967.01330110026004