Hemolysis of 40% hematocrit, Albunex(R)-supplemented human erythrocytes by pulsed ultrasound: Frequency, acoustic, pressure and pulse length dependence

The dependence of hemolysis produced by pulsed ultrasound on ultrasound frequency, acoustic pressure and pulse length was explored, Human erythrocytes (40% hematocrit; in Albunex(R)-supplemented autologous plasma) were exposed (60 s) to 20 or 200 mu s pulses of ultrasound at frequencies of 1.02, 2.24 or 3.46 MHz and at peak negative pressures [P-] ranging from 0.0 to similar to 3.0, MPa in 0.5 MPa increments, The duty factor was 0.01. At each frequency, hemolysis increased with increasing acoustic pressure and depended weakly on pulse duration, At relatively high acoustic pressures, hemolysis depended strongly on ultrasound frequency; at lower pressures, the frequency dependence was weaker, The potential clinical significance of ultrasonic hemolysis is discussed. (C) 1997 World Federation for Ultrasound in Medicine & Biology.