A NEW IN-VIVO METHOD FOR THE DIRECT MEASUREMENT OF NUTRIENT ARTERY BLOOD-FLOW

A new method of directly measuring nutrient artery blood flow using ul trasonic probes is described. These probes have provided reproducible results in our experiments. Advantages of ultrasonic probes include th e direct measurement of blood flow through small arteries, ease of use , accuracy of measurement, applicability to a wide range of vessel dia meters, the capability of chronically monitoring blood flow over time using permanently implanted probes, and the ability to use the method in conjunction with previous methods of bone blood flow measurement. T he method is limited to the extent that only the contribution of the n utrient artery can be measured and total bone blood flow cannot be ass essed. Tibial nutrient arterial flow and cardiac output were measured in adult mongrel dogs. Two experiments were performed: 1) bilateral ba seline tibial nutrient artery blood flow measurements over time and 2) tibial nutrient blood flow comparing inhaled anesthesia (halothane/ni trous oxide/oxygen) and intravenous anesthesia (pentobarbital [Nembuta l]). In 15 mongrel dogs, tibial nutrient artery blood flow averaged 1. 46 +/- 0.72 ml/min (0.09 +/- 0.05 percent of cardiac output and 2.75 /- 1.95 mL/min/100 g of bone). No significant difference in tibial nut rient artery blood flow was observed between animals given intravenous and inhaled anesthesia (P>.05). As a basic research tool, transit-tim e ultrasonic blood flow technology may be useful. The method is relati vely easy to use and may be applied to experimental models designed to investigate various physiologic and pathologic states frequently enco untered in orthopedics leg, shock, sepsis, fractures).