Previous recommendations regarding the "safe" period of tourniquet hemostasis were based largely on studies of ischemia distal to the tourniquet. This study quantitatively analyzed skeletal muscle injury induced beneath and distal to a pneumatic tourniquet applied to the hindlimbs of rabbits for 1, 2, or 4 hours with a cuff inflation pressure of 125, 200, or 350 mm Hg. Technetium Tc 99m pyrophosphate incorporation after systemic injection (Tc 99 uptake) and correlative histology were used to evaluate tissue damage 2 days after tourniquet application. Compared with the contralateral control limbs, compression and ischemia induced statistically significant increases in Tc 99 uptake in the thigh and leg regions of all groups. Pyrophosphate incorporation was significantly greater in the thigh region than in the leg region after 2 hours of compression in the 200 and 350 mm Hg pressure groups and following 4 hours of compression in all pressure groups. Focal and regional fiber necrosis and degeneration were observed in thigh muscles after 2 hours of tourniquet compression. Two hours of continuous tourniquet application at clinically relevant cuff inflation pressures induced significant skeletal muscle necrosis beneath the tourniquet. Use of the lowest possible inflation pressure for a limited duration should minimize the degree of tissue injury caused by tourniquet application.
Bibliographical noteFunding Information:
From the Division of Orthopaedics and Rehabilitation, University of California, San Diego, Calif.; the Department of Anatomy and Department of Hand Surgery, University of Umei, Sweden; the Department of Orthopaedics, Gothenburg University, Sweden; and the NASA Ames Research Facility, Moffett Field, Calif. Supported by The Veterans Administration, NIH (AM-25501 and AR-07484); the Orthopaedic Research and Education Foundation, the Swedish Medical Research Council, Gothenburg University and the Institute for Applied Biotechnology, Gothenburg, Sweden; and by the Zimmer Corporation. Received for publication June 18, 1990; accepted in revised form Sept. 15, 1990. No benefits in any form have been received or will be received from a commercial party related directly or indirectly to the subject of this article. Reprint requests: Robert A. Pedowitz, MD, Division of Ortbopaedics and Rehabilitation (H-894), University of California, San Diego Medical Center, 225 Dickinson St., San Diego, CA.