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Tourniquets are an effective means of arresting life‐threatening external haemorrhage from limb injury. Their use has not previously been accepted practice for pre‐hospital civilian trauma care because of significant concerns regarding the potential complications. However, in a few rare situations tourniquet application will be necessary and life‐saving. This review explores the potential problems and mistrust of tourniquet use; explains the reasons why civilian pre‐hospital tourniquet use may be necessary; defines the clear indications for tourniquet use in external haemorrhage control; and provides practical information on tourniquet application and removal. Practitioners need to familiarise themselves with commercial pre‐hospital tourniquets and be prepared to use one without irrational fear of complications in the appropriate cases.
Tourniquets are an effective means of arresting life‐threatening external haemorrhage from limb injury. However, their use remains a subject of much debate, with many unanswered questions and significant concerns regarding the potential complications from their use.1 For these reasons tourniquets are often discouraged in contemporary pre‐hospital civilian trauma care.
The first reported use of a tourniquet for haemorrhage control after wounding was by a French army surgeon called Etienne Morel in 1674. The term tourniquet originated from the French “tourner” meaning “to turn”. Before this, tight bandages proximal to wounds were being used by surgeons as an aid to amputation as early as 1517.2
In 1874 Lister described the use of a tourniquet in elective civilian practice to obtain a bloodless field during the excision of a tuberculous wrist joint.2 Indeed the majority of knowledge today regarding tourniquet use comes from elective theatre cases for orthopaedic or vascular surgery.
By 1916 the complications of tourniquet use were being identified and the Royal Army Medical Corp Journal stated “we are inclined to think that tourniquets are an invention of the Evil One”.3 However, recent military data have estimated that 10% of all battlefield deaths are caused by extremity haemorrhage (accounting for 60% of preventable deaths)4 and analysis of data from the Vietnam war found that 7% of combat deaths may have been prevented by the use of a limb tourniquet.5 In a 4 year period of tourniquet use by the Israeli Defence Force there were no reported deaths from uncontrolled limb haemorrhage among 550 injured patients.6
Even in civilian traditional teaching, Advanced Trauma Life Support (ATLS) recommends that in the presence of major arterial haemorrhage “the judicious use of a pneumatic tourniquet may be helpful and lifesaving”.7
This article aims to:
Ovid Medline (R) 1966 to August Week 1 2006 using terms exp Tourniquets/AND [exp Hemorrhage/OR haemorrhage.mp OR bleeding.mp OR exsanguination.mp] AND limit to (Humans and English language). PubMed using the mesh terms “Tourniquets” AND “Hemorrhage”. The Cochrane Database of Systematic Reviews 2006 Issue 3 using term “Tourniquets” found no relevant articles.
It is likely that the use of tourniquets for external haemorrhage control may have fallen out of vogue for the following reasons:
The military have been at the forefront of reintroducing tourniquet use into modern practice. The new military trauma paradigm teaches that control of catastrophic haemorrhage takes priority over airway and breathing assessment.13 Effective modern combat body armour means that extremity trauma now accounts for the highest anatomical distribution of injury. In the combat setting high velocity penetrating trauma and blast injury are common, resulting in extensive wounding and mangled extremities.14 Soldiers require a rapid system of haemorrhage control which can be self applied while under fire. The requirement for continued use of a tourniquet is then reassessed when the fire‐fight is won.
In contrast in civilian practice the medical practitioner is generally working in a safe environment (not “under fire”) with early access to definitive care; furthermore, the common mechanisms of non‐battle injury do not normally produce catastrophic external haemorrhage.
However, there are a number of examples where tourniquet use may be applicable in civilian practice:
Indications for tourniquet use will be rare in the civilian pre‐hospital environment. In the majority of cases external haemorrhage will be controlled by applying a stepwise approach (fig 11).
However, immediate application of a tourniquet may be justifiable in the following examples:
The pre‐hospital practitioner should be familiar with a particular commercial tourniquet that has been proven in studies to be effective, rather than using an improvised device that has been demonstrated to take more time to apply or may lead to an increased risk of complications.16,17,18
With a wide availability of commercial tourniquets there have been several experimental studies using human volunteers comparing different types.16,17,18,19 User characteristics such as ease of self‐application under fire are largely inapplicable in the civilian pre‐hospital setting (the exception being tactical firearms police).
However, the physical characteristics of a tourniquet are relevant. The tourniquet must completely and consistently occlude arterial blood flow. The pressure required to occlude blood flow in a limb increases exponentially with the circumference of the limb. For this reason significantly more tension is required to occlude the arterial blood supply of a leg compared to an arm.
There is also an inverse relationship between tourniquet width and the minimal pressure required to occlude arterial blood flow. However, as width increases the amount of tissue that must be compressed increases, requiring an increased effort to produce tension. Also, as the width of the strap increases, the strap tends to bow, transmitting relatively more pressure to the centre rather than the edges and therefore reducing functional width.20
The UK Defence Medical Services selected the Combat Application Tourniquet (CAT, North American Rescue Products, Inc, USA) for operational use after experimental studies showed 100% effectiveness in occluding distal arterial flow using human volunteers.16Figure 22 shows the CAT tourniquet applied to the lower limb.
Principles of tourniquet application include: placement of the tourniquet as distal as possible, but at least 5 cm proximal to injury; sparing joints as much as possible; and ideally applied directly onto exposed skin to avoid slipping.6
Effectiveness of tourniquet use will be determined by cessation of external haemorrhage and not by the presence or absence of a distal pulse. If it is ineffective the tourniquet should be tightened or repositioned. If the tourniquet is still ineffective (unlikely) the health care provider may consider a second tourniquet placed just proximal to the first. Slight oozing may still occur in a limb amputation despite effective application if there is medullary bone blood flow.20
The time of application should be recorded and handed over to the receiving emergency department staff.
The practice of exposing the limb to cold environmental temperatures was credited for successful limb salvages after prolonged tourniquet applications (>8 h) in the second world war.21 Local hypothermia has been studied experimentally and suggested as a method to prolong tourniquet times before muscle ischaemia in elective models of tourniquet use in limb surgery.22 In animal studies on rats reducing the limb temperature to 4°C by application of cold gel packs was found to protect against tourniquet neuropathy after 3 h of tourniquet use.23 In animal studies on pigs, in the group with skin temperatures reduced to a mean of 9.3°C and muscle temperatures reduced to a mean of 16°C, after 3 h tourniquet application, a reduction in muscle damage was found in the local hypothermia group.24 Exposing the limb with a tourniquet to the environment to allow cooling or artificially trying to achieve local hypothermia may therefore be a consideration in situations with prolonged evacuation times to definitive care.
Assuming that the tourniquet has been applied for the correct indications a decision will need to be made regarding its continued use. This will depend on several factors including: whether the external haemorrhage is from an isolated injury; if the other injuries have been stabilised; the current haemodynamic status of the patient; estimated journey time to hospital; and the medical resources available. If transit time is expected to be <1 h, the tourniquet should remain in situ until the patient is in the operating theatre where direct surgical control of haemorrhage can be undertaken.
If the transit time is >1 h and if there is an isolated injury (or the other life‐threatening injuries have been managed adequately) and the patient has stable vital signs, a “trial of tourniquet conversion” may be attempted. It is possible that after a period of time of reduced arterial flow from tourniquet use, clotting will have occurred sufficiently to arrest haemorrhage, allowing simpler methods to be effective and reducing the complications from continued tourniquet use. Before release of the tourniquet the practitioner should have secured wound packing (including haemostatic agents) and application of direct pressure over the bleeding point (with windlass dressing). If careful release of the tourniquet then results in a return of uncontrollable external haemorrhage, the tourniquet should be replaced and not removed until the patient is in the operating theatre (a “tourniquet of last resort”).
The practitioner should select the most appropriate hospital for the patient and relay an alert message to the emergency department to facilitate expeditious transfer to the operating theatre if necessary. Remember to give the time of tourniquet application in handover and remind the emergency department that it is present, particularly in patients with multiple injuries. Hospital staff should be strongly discouraged from removing the tourniquet until the patient is in theatre.
Any amputated limb should ideally be transported with the patient to hospital even if it appears unsalvageable as tissue may be utilised for skin cover and reconstruction of the stump (this will rarely be practical or appropriate in the military setting).
In rare situations tourniquet application will be necessary and lifesaving in the civilian pre‐hospital setting. Tourniquets are no longer only considered as a “last resort” device. Practitioners should familiarise themselves with this simple piece of equipment and be prepared to use it in appropriate cases without an irrational fear of complications.
Competing interests: None declared