The pressure immobilisation technique is a first aid treatment used as a way to treat spider bite, snakebite, bee, wasp and ant stings in allergic individuals, blue ringed octopus stings, cone shell stings, etc. The object of pressure immobilisation is to contain venom within a bitten limb and prevent it from moving through the lymphatic system to the vital organs. This therapy has two components: pressure to prevent lymphatic drainage, and immobilisation of the bitten limb to prevent the pumping action of the skeletal muscles.
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Evidence
As of 2008, clinical evidence for pressure immobilisation for snakebite was not well established, with clinicians recommending its continued practice for certain snakes (including all snakes in Australia), but calling for further research. See snakebite#Pressure immobilization for details.
Technique
Pressure is preferably applied with an elastic bandage. Alternatively it is possible to wrap much of the limb with an intact long-sleeved shirt, but it is difficult to apply an ideal even pressure with an inelastic fabric, and one shirt may not be long enough. Bandaging begins two to four inches above the bite (i.e. between the bite and the heart), winding around in overlapping turns and moving up towards the heart, then back down over the bite and past it towards the hand or foot. Then the limb must be held immobile: not used, and if possible held with a splint or sling. The bandage should be about as tight as when strapping a sprained ankle. It must not cut off blood flow, or even be uncomfortable; if it is uncomfortable, the person will unconsciously flex the limb, defeating the immobilisation portion of the therapy. The location of the bite should be clearly marked on the outside of the bandages. Some peripheral edema is an expected consequence of this process.
History
The technique was developed in the 1970s by Australian medical researcher Struan Sutherland.
Today, it is the recommended first-aid procedure in Australia for treating most spider bites and all snake bites.