The pressure immobilisation technique (PIT) retards the flow of lymph by which venoms gain access to the circulation. It has also been shown that there may be inactivation of certain venoms and venom components when the injected venom remains trapped
in the tissues by the pressure bandage.
The PIT is recommended for application to bites and stings by the following creatures:
All Australian venomous snakes, including sea snakes.
Funnel Web spider.
Pressure Immobilization Technique (PIT) is not to be used on spider or insect bites (except the Funnel web spider).
Patient Factors & Considerations
The Snakebite Bandage (with continuous indicator) is the preferred bandage to achieve optimal compression with the Pressure Immobilisation Technique.
In absence of the snakebite bandage, elastic bandages (10-15 cm wide) can be used and are preferred over crepe bandages. If neither are available, clothing or other material should be used.
The bandage should be applied over existing clothing if possible.
If the bite is not on the limb, firm direct pressure on the bite site may be useful.
Resuscitation takes precedence over the PIT application, however PIT should be applied as soon as possible to minimise further venom flow.
Apply a broad elasticated pressure bandage (10-15cm wide) over the bite site as soon as possible.
Apply a snakebite bandage, commencing at the distal end of the affected limb (i.e. fingers or toes of the bitten limb) and extending upwards, covering as much of the limb as possible.
Apply enough tension to the snakebite bandages so that the continuous indicator forms a 1.5cm x 1.5cm square, rather than a rectangle in it's un-stretched state. This indicates that firm compression is achieved in the limb.
If using elasticated bandages without the continuous compression indicator, the bandage should be firm and tight and you should be unable to easily slide a finger between the bandage and the skin.
Splint the limb.
Keep the patient and the limb completely at rest.
Assess arterial blood follow distal to pressure dressings via cap refill.
Mark on the Pressure Immbobilisation bandage with a marker exactly where the bite site(s) are.