Hazards of Narrow, Non-Pneumatic Elastic Ring tourniquets
Hazards and injuries associated with elastic ring tourniquets
A recent report of a serious injury and a death associated with the use of a non-pneumatic, elastic ring tourniquets provides motivation for reviewing the underlying mechanism of tourniquet-related hazards and injuries, and for establishing tourniquet safety guidelines for minimizing the probability of such injuries. Elastic, non-pneumatic tourniquets have been associated with numerous reports of serious and irreversible injuries to nerves, muscles, blood vessels and soft tissues since the late 1800s (eg [1-8]). The level of pressure applied by elastic non-pneumatic cuffs, and the pressure gradients produced when used as tourniquets or exanguinators, is not known to, or controllable by, clinical users. However, many published reports show that such injuries largely result from the application of unnecessarily high tourniquet pressure levels, well above the minimum pressure needed to stop arterial blood flow (eg [9-12]), and from the application of cuffs producing a high pressure gradient along a patient’s limb (eg [11, 13, 14]).
Figure 1: Elastic ring tourniquet on an arm. Note the narrow elastic ring applying high pressure and high pressure gradient to the underlying limb. Learn about hazards of high pressures and high pressure gradients.
The introduction of pneumatic tourniquets has allowed the tourniquet pressure level to be known, regulated, and maintained (eg [10, 14-16]). Additionally, more recent improvements in the design of certain pneumatic tourniquet cuffs reduce the pressure gradient produced by the cuff on the underlying limb to be reduced, thus reducing another mechanism of injury. (eg [13,17-21]). It is now well established in the clinical literature, and by decreasing reports of the incidence and severity of pneumatic tourniquet injuries, that lower tourniquet pressure levels, and lower tourniquet pressure gradients beneath cuffs, are associated with lower probabilities of tourniquet-related injuries (eg [22]). Elastic and other non-pneumatic tourniquets which do not provide for the monitoring, control and minimization of tourniquet pressure levels and pressure gradients are hazardous for surgical usage (eg [1]). In contrast, new personalized tourniquet instruments allow the optimal “limb occlusion pressure” (LOP) to be identified for each patient, surgery, application (etc, from definition [14]). Optimal tourniquet safety results when LOP is routinely used to establish lowest tourniquet pressures in conjunction with tourniquet cuffs that produce lowest cuff pressure gradients. Published evidence and evolving clinical practice guidelines recognize that employing such low tourniquet pressure levels and cuffs producing low tourniquet pressure gradients lowers the probability of tourniquet-related hazards and injuries.
Figure 2: A comparison of applied pressures and pressure gradients typically produced by (a) a modern pneumatic surgical tourniquet cuff, (b) a non-pneumatic, non-surgical strap-type tourniquet and (c) a non-pneumatic elastic ring designed to combine exsanguination and tourniquet functions. Each tourniquet was selected and applied as recommended by the respective manufacturer to stop arterial bloodflow in an upper limb. Higher levels of pressure and higher pressure gradients are associated with higher probabilities of patient injuries. Reproduced from McEwen J., Casey V., (2009). CMBEC32. Calgary, Canada; 2009 May 20-22 [13].
Sources
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[7] Moldaver J. Tourniquet paralysis syndrome. AMA archives of surgery. 1954 Feb 1;68(2):136-44.
[20] McEwen JA, Inkpen K, Younger A. Thigh tourniquet safety. Surgical Technologist. 2002;34(7):8-19.