Development of an Ultrasonic Tourniquet System for Surgical Applications

Abstract

An ultrasonic tourniquet system for surgical applications is being developed to dynamically adjust tourniquet cuff pressure for the duration of a surgical procedure to maintain a bloodless surgical field. User intervention is not required during operation, allowing the surgeon to focus on the surgery. Although significant progress has be made in the measurement of preoperative limb occlusion pressure, these methods are not ideal due to their inability to respond to fluctuations in blood pressure and other physiological parameters during surgery, which may result in loss of limb occlusion or more tourniquet pressure than necessary being used. The ultrasound tourniquet system relies on ultrasound measurements to automatically determine the lowest tourniquet pressure required to maintain occlusion of the limb's main artery. A control algorithm determines if there is blood flow underneath the transducers, and increases or decreases the tourniquet pressure so that the depth of penetration of blood in the limb artery is proximal to a predetermined location underneath the cuff. The control algorithm continuously monitors the depth of penetration of the limb artery during surgery in order to account for blood pressure variations and keeps the surgical field clear of blood for the duration of the procedure.