HEMOLYSIS OF ALBUNEX-SUPPLEMENTED, 40-PERCENT HEMATOCRIT HUMAN ERYTHROCYTES IN-VITRO BY 1-MHZ PULSED ULTRASOUND - ACOUSTIC PRESSURE AND PULSE LENGTH DEPENDENCE

The tested hypothesis was that ultrasound-induced hemolysis in blood s upplemented with a microbubble contrast agent varies with ultrasound i ntensity and pulse duration, Human erythrocytes in autologous plasma c ontaining 3.6% v:v Albunex microspheres were exposed to 1.07-MHz ultra sound pulses of 5 to 1000 mu s at SPTP intensities of 0 to 1100 W/cm(2 ), The dependence of hemolysis on the mechanical index (MI) value of t he exposures was also examined, Ultrasound-induced hemolysis: (1) was evident at all pulse/intensity combinations; (2) increased generally w ith increasing pulse duration at constant intensity; and (3) increased with increasing MI at constant pulse duration, For pulses of 10 to 30 mu s, ultrasound-induced hemolysis remained low (less than or equal t o 2%) at MI values < similar to 2 and increased sharply with further i ncrease in MI; for 5-mu s pulses, this abrupt increase in hemolysis wa s associated with a larger MI (approximately 3).