Image guided acoustic hemostasis

Previous studies have shown that high intensity focused ultrasound (HIFU) can successfully control visible bleeding from solid organ injuries. This study investigates the ability of ultrasound image‐guided HIFU to arrest occult hemorrhaging in the posterior liver parenchyma using a pig model. The image‐guided HIFU device consisted of an intraoperative imaging probe and a spherically‐curved HIFU transducer with focal length of 3.5 cm, frequency of 3.23 MHz, and focal acoustic intensity of 2350 W/cm². A total of 19 incisions (14 HIFU‐treated and 5 control incisions) were made in five pig livers. The incisions were 30 mm long and 7 mm deep with HIFU application occurring within 20 s of making an incision. Hemostasis was achieved in all treated incisions after a mean ± SD of 65±15 s of HIFU application. The mean blood loss rate of the control incisions initially and after seven minutes was 0.268 and 0.231 mL/s, respectively. Subsequent histological analysis showed coagulative necrosis of liver tissue around the incision which appeared to be responsible for hemostasis. Ultrasound image‐guided HIFU offers a promising method for achieving hemostasis in surgical settings in which the hemorrhage site is not accessible.