Cell damage by lithotripter shock waves at high pressure to preclude cavitation

Acoustic cavitation has been implicated as a cause of cell damage by lithot ripter shock waves, particularly under in vitro conditions. When red blood cells were exposed to shock waves (from an electrohydraulic lithotripter) w hile under high hydrostatic pressure (> 80 atm), cell lysis was dramaticall y reduced over that seen at atmospheric pressure, which is consistent with damage due to acoustic cavitation, However, even at > 120 atm of pressure, lysis was still 97% above that of cells not exposed to shock waves, reveali ng significant damage that apparently was due to mechanisms other than cavi tation, Hydrostatic pressure alone did not cause cell lysis, and shock-wave -dependent damage occurred when the cells were in fluid suspension, or when they were centrifuged to the end of the vial. Shock-wave damage at high pr essure increased with increasing shock-wave number, and was seen at 24 and 20 kV, but not at 16 kV, This shock-wave damage at high pressure makes up a noteworthy portion of the total cell injury seen at atmospheric pressure ( about 10% at 24 kV), suggesting significant noncavitational injury to cells in vitro. Because cavitation occurs far more readily in vitro than in vivo , the noncavitational damage seen in the present study could represent a su bstantial portion of cell injury seen in vivo with shock-wave lithotripsy, (C) 1999 World Federation for Ultrasound in Medicine & Biology.