Use of high-intensity focused ultrasound to control bleeding

Objective: High-intensity focused ultrasound (HIFU) has been shown to be ef fective in controlling hemorrhage from punctures in blood vessels. The obje ctive of the current study was to investigate the capability of HIFU to sto p bleeding after a more severe type of vascular injury, namely longitudinal incisions of arteries and veins. Methods: The superficial femoral arteries, common femoral arteries, carotid arteries, and jugular veins of four anesthetized pigs were exposed surgica lly. A longitudinal incision, 2 to 8 mm in length, was produced in the vess el. HIFU treatment was applied within 5 seconds of the onset of the bleedin g. The HIFU probe consisted of a high-power, 3.5-MHz, piezoelectric transdu cer with an ellipsoidal focal spot that was 1 mm in cross section and 9 mm in axial dimension. The entire incision area was scanned with the HIFU beam at a rate of 15 to 25 times/second and a linear displacement of 5 to 10 mm . A total of 76 incisions and HIFU treatments were performed. Results: Control of bleeding (major hemosatsis) was achieved in all 76 trea tments, with complete hemostasis achieved in 69 treatments (91%). The avera ge treatment times of major and complete hemostasis were 17 and 25 seconds, respectively. After the treatment, 74% of the vessels in which complete he mostasis was achieved were patent with distal blood flow and 26% were occlu ded. The HIFU-treated vessels showed a consistent coagulation of the advent itia surrounding the vessels, with a remarkably localized injury to the ves sel wall. Extensive fibrin deposition at the treatment site was observed. Conclusion: HIFU may provide a useful method of achieving hemostasis for ar teries and veins in a variety of clinical applications.