AN EXPERIMENTAL STUDY OF PRESSURE LOSSES THROUGH CATHETERS,

In an effort to quantify the pressures necessary to pump blood through surgical catheters during extracorporeal blood-pumping procedures, tests were performed in which water was pumped through a number of different test catheters. Water was used because of the problem of obtaining sufficient quantities of blood for such a purpose. The test catheters were constructed so that the effect of internal diameter, length of the reduced diameter section, and shape of the area transition region could be studied. The tests were made under both steady and pulsed flow conditions. The results showed that for small diameter catheters, pressures as high as 2850 mm Hg are necessary to obtain steady flows of 4 lmin of water. For blood, the corresponding pressures would be even higher. The pulsed flow results did not show any clear trends in comparison with the steady flow results, but this may be due in part to the test circuit employed. Author