Liver hemostasis using high-intensity focused ultrasound

Liver hemorrhage, the major cause of death in hepatic trauma, is notoriously difficult to control. We report on the use of high-intensity focused ultrasound (HIFU) to arrest the bleeding from incisions made in rabbit livers. A HIFU transducer, with a spherically curved aperture of 6.34 cm² area, a focal length of 4 cm and a frequency of 3.3 MHz was used. In approximately 94% of the incisions, the hemorrhage was reduced to a slow oozing of blood in less than 2 min. The maximum temperature of liver tissue around the incision area, during HIFU application was measured to be 86°C. The mechanism of hemostasis, confirmed by histological examination, appears to be coagulative necrosis of a volume of liver tissue around the incision. We believe that acoustic hemostasis, with the unique characteristic of 'volume cauterization,' offers a novel method for the management of liver hemorrhage and, thus, has major clinical implications.