Tourniquets: villain or hero?
.Christian thrash heavy metal band formed in 1989. Their first album was called ‘Stop the bleeding’…
Case: The team are called to a freeway scene where a motorcyclist has hit a tree. The victim is obviously shocked and has a reduced GCS. His left leg has been severed just below the knee and the stump is bleeding profusely. The amputated portion of his limb is 10 metres away in the grass verge. The HEMS team apply a MAT* to the left thigh and then intubate and ventilate the victim. They perform bilateral thoracostomies prior to transfer by helicopter to a trauma centre. He is taken straight to theatre where the orthopods perform an above knee amputation. Before the HEMS team leave, the Crewie is asked to pick up the severed portion of the left leg. When they ask what they should do with it, the paramedic suggests he put it in the ‘boot’?!!?
Challenge: When, why and how to correctly apply a pre-hospital tourniquet.
Tourniquets fall from grace: (Not the rock band!?!)
- Majority of external haemorrhage can be controlled by direct pressure.
- Previously tourniquets have been used inappropriately when not clinically indicated.
- Preventing arterial blood flow to a limb will result in ischaemia.
- Continuous application > 2hrs can result in permanent nerve injury, muscle injury, vascular injury and skin necrosis.
The general conclusion is that a tourniquet can be left in place for up to 2hrs with little risk of permanent ischaemic injury. However the majority of the literature looks at pneumatic tourniquets in elective theatre cases with normovolaemic patients.2
Lakstein found a 5% complication rate in 110 applications of a pre-hospital tourniquet and identified a mean ischaemic time of 78 minutes with no complications.3 None of the complications resulted in limb loss.
Learning Points: Tourniquets are an effective means of arresting life-threatening external haemorrhage from limb injury.4 The new military trauma paradigm teaches; control of catastrophic haemorrhage takes priority over airway and breathing assessment.5
- Extreme life-threatening limb haemorrhage or limb amputation/ mangled limb.
- Life-threatening limb haemorrhage not controlled by simple methods.
- To allow immediate management of airway or breathing problems. (then reassess need in circulatory assessment).
- Point of significant haemorrhage not peripherally accessible, e.g. entrapment.
- Major incident or multiple casualties with extremity haemorrhage and lack of resources.
- When benefits of preventing death from hypovolaemic shock by cessation of ongoing external haemorrhage is greater than the risk of limb damage or loss from ischaemia caused by tourniquet use.6
- Re-perfusion injury: inflammation induced injury of previously hypo-perfused areas and organ damage from systemically released mediators.
- Increased bleeding from distal tissues when venous outflow is obstructed but arterial blood flow is inadequately occluded.
- After resuscitation of the hypotensive patient, a higher systolic pressure may re-start bleeding.
- Periodical loosening, in an attempt to reduce limb ischaemia, has lead to incremental exsangination.
- A properly applied tourniquet is painful and this has led to inadequate tightening or premature removal.
- Familiarise yourself with your own kit. In our case, the *Mechanical Advantage Tourniquet by Pyng Medical.
- 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.7
- Placement of the tourniquet as distal as possible, but at least 5 cm proximal to injury.
- Spare joints as much as possible, ideally onto exposed skin.
- Effectiveness determined by cessation of external haemorrhage, not by presence or absence of a distal pulse.
- Slight oozing may still occur especially if there is medullary bone blood flow.
- If ineffective, tighten or reposition.
- Still ineffective, consider a second tourniquet placed just proximal to the first.
- Application time should be recorded and device should be removed in theatre.
Consider exposing the tourniqueted limb to the environment to allow cooling or artificially trying to achieve local hypothermia.8
Summary: Use a commercial tourniquet in specific pre-hospital situations.9 Make sure the intervention has been effective and document the application time. Get the victim to a trauma theatre as soon as possible.
“Sentio aliquos togatos contra me conspirare”