How Safe Are Non-Pneumatic Tourniquets?
Pneumatic tourniquets are commonly used in surgery to safely
establish a bloodless surgical field in a portion of a limb over
a time period suitably long for the performance of a surgical
procedure. It is estimated that at least 15,000 surgical
procedures are performed each day on limbs with the benefit of
pneumatic tourniquet systems. The introduction and widespread use
of automatic tourniquet systems, with microcomputer control and
improved pneumatic cuff designs, has greatly reduced the reported
severity and number of tourniquet-related hazards and injuries[1-3].
It is well established in the medical literature that the
probability of tourniquet-related injuries increases as
tourniquet pressure increases, and as the pressure gradients near
the edges of tourniquet cuffs increase eg[2,4-8,10,13].
The widespread adoption and use of such automatic tourniquets
employing microprocessor technology, together with improved
designs of pneumatic tourniquet cuffs, has greatly improved the
safety, accuracy and reliability of tourniquets in surgery. The
resulting decrease in the number of reported hazards and
incidents was accompanied by a reduction in risk class by the
(US) FDA: in 1996, the FDA classified pneumatic tourniquets as
Class I medical devices (indicating that they present minimal
harm to the user and do not present a reasonable source of injury
through normal use), and the FDA thereafter exempted pneumatic
tourniquets from its (510k) pre-market notification and clearance
procedures. Modern pneumatic tourniquets are used in an estimated
15,000 orthopaedic and non-orthopaedic surgical procedures daily
in the US and elsewhere, facilitating surgery by reliably
establishing a bloodless surgical field with relative safety.
Pneumatic tourniquets have recently been developed for
military and emergency use, based on surgical designs proven to
be safe and effective over many years. Such pneumatic devices are
deployed in Afghanistan and Iraq and in other pre-surgical
emergency settings. Pneumatic military tourniquets are more
commonly used by medics than by individual soldiers in combat,
but both types are designed to be suitable for rapid, one-handed
self-application in the field. In a recent study, the early use
of both types of military tourniquets (pneumatic and
non-pneumatic) when shock was absent was strongly associated with
saved lives, pre-hospital use was also strongly associated with
lifesaving, and no limbs were lost due to use of these military
tourniquets. In another paper reporting on the
same study, pneumatic military tourniquets were rated 92%
effective and non-pneumatic tourniquets were rated 79% effective.
|Fig. 1 Narrow, non-pneumatic strap
tourniquet designed for one-handed self
application in certain military settings.
||The comparatively narrow, non-pneumatic tourniquet
straps were developed to be very small in size and light
in weight so they could be carried in backpacks by all
soldiers, and were developed to be suitable for rapid
one-handed self-application by wounded soldiers in combat
situations. While effective in helping to stop
potentially fatal arterial blood flow in combat, such
narrow non-pneumatic tourniquet straps may produce
hazardously high, inconsistent and uncontrolled pressures
around limbs and may further produce high pressure
gradients near the strap edges.
Very recently, it has been suggested by some that
non-pneumatic tourniquets, including elastic bandages, elastic
rings and non-elastic straps might be employed in pre-hospital
civilian use and even in surgery, as they were in the 19th
century. The uncritical acceptance and use of such non-pneumatic
tourniquets in non-military settings and in surgery for extended
periods, without investigation of applied pressure levels and
applied pressure gradients and with limited evidence of their
safety, may unnecessarily increase the incidence of
tourniquet-related injuries in surgical patients to earlier
levels, and may expose users in civilian settings to potential
legal liability for non-military users.
Non-pneumatic tourniquet devices for stopping arterial
bleeding may not be as safe as pneumatic tourniquets in civilian
settings, where pneumatic tourniquets with proven safety and
efficacy are available and where one-handed self-application is
not an essential consideration. A recent study confirmed that
non-pneumatic tourniquet straps and non-pneumatic elastic rings
produce substantially higher applied pressures and higher
pressure gradients when selected and used to stop arterial
bloodflow according to manufacturers instructions (see Fig.
|Fig. 2 Applied pressures and pressure
gradients typically produced by (a) a modern pneumatic
surgical tourniquet cuff, (b) a non-pneumatic,
non-surgical military tourniquet designed for
self-application on the battlefield, and (c) a
non-pneumatic elastic ring designed in an attempt to
combine exsanguination and tourniquet functions. Higher
levels of pressure and higher pressure gradients are
associated with higher probabilities of patient injuries,
|Such higher pressure levels and higher pressure
gradients are associated in the clinical literature with
higher probabilities of patient injuries. Additional
caution is suggested by a recent anecdotal report of
possible nerve, muscle, and soft tissue injuries
associated with a commercial, non-pneumatic elastic ring
recently developed for use as a surgical tourniquet and
tourniquets have proven to be effective in stopping
arterial bleeding in combat situations, as have narrow,
light-weight non-pneumatic tourniquet straps.
|Fig. 3 Narrow, non-pneumatic elastic
ring tourniquets produce substantially higher
applied pressures and higher pressure gradients.
|Fig. 4 Wide, pneumatic tourniquets
have proven safety, lower pressures and lower
||For both of these types of military tourniquets,
small size, light weight and the requirement that they be
suitable for one-handed self-application are essential
considerations. However, for civilian pre-hospital
applications and civilian surgical applications these are
not considerations. Thus to minimize potential legal
liability, much further investigation is warranted before
there is uncritical acceptance and use of non-pneumatic
tourniquet straps, or non-pneumatic elastic tourniquet
rings, when pneumatic tourniquets with proven safety,
lower pressures and lower pressure gradients are
References for educational viewing only
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