Surgical tourniquets enable surgeons to work in a bloodless operative field by preventing blood flow to a limb. This allows surgical procedures to be performed with improved precision, safety and speed. In venipuncture, small straps are used as partially occluding tourniquets to show the vein more clearly. Tourniquets are widely used in orthopedic and plastic surgery, as well as in intravenous regional anesthesia (Bier block anesthesia) where they serve the additional function of preventing local anesthetic in the limb from entering general circulation.
Pre-modern surgical tourniquets
editAdvances in surgical tourniquets
editIn the early 1980s, microprocessor-controlled pneumatic tourniquets were invented by Dr James McEwen, PhD [1][2]. Automatic tourniquets based on this invention are now standard equipment in operating rooms worldwide, and these systems have significantly improved the safety and convenience of tourniquet use.
Despite many advances in tourniquet technology, tourniquet-related injuries continue to be of concern[3]. High pressures under a tourniquet cuff can cause nerve, muscle and skin injury. Minimizing tourniquet pressure, reducing inflation time and using a microprocessor-controlled pneumatic tourniquet, which allows pressure to be accurately monitored and controlled, reduce the risk of tourniquet-related injury.
Surgical tourniquet equipment
editModern pneumatic tourniquets have three basic components: an inflatable cuff, a compressed gas source, and an instrument which automatically monitors and controls cuff pressure. The cuff is secured around the limb proximal to the operative site. Pressure is exerted on the circumference of the limb by means of compressed gas which is introduced into the tourniquet cuff by a microprocessor-controlled source, via connection tubing. When sufficient pressure is exerted, vessels and arteries beneath the cuff become temporarily occluded, preventing blood flow past the cuff. While the cuff is inflated, the tourniquet system automatically monitors and maintains the pressure chosen by the user. Cuff pressure and inflation time are displayed, and an audiovisual alarm alerts the user to alarm conditions, such as a cuff leak.
References
edit- ^ US patent 4469099, McEwen, James A., "Pneumatic Tourniquet", issued 1984-09-04
- ^ US patent 4479494, McEwen, James A., "Adaptive Pneumatic Tourniquet", issued 1984-10-30
- ^ Murphy CG, Winter DC, Bouchier-Hayes DJ. “Tourniquet injuries: Pathogenesis and modalities for attenuation.” Acta Orthop Belg. 2005; 71(6):635-645.