Pressure Immobilisation Technique: Why It Works for Snakebite and Venomous Bites
Pressure Immobilisation Technique: Why It Works for Snakebite and Venomous Bites
The pressure immobilisation technique is a first aid method used to slow the spread of venom after certain bites and stings. A firm bandage is applied over the bite area and along the entire limb, and the limb is then immobilised with a splint. This slows lymphatic movement, which helps delay venom travelling through the body until medical treatment is available.
What Is the Pressure Immobilisation Technique?
The Pressure Immobilisation Technique (often called PIT) is a first aid method used in Australia to manage certain venomous bites and stings.
The technique involves two key steps:
• applying a firm pressure bandage over the bite area and along the limb
• immobilising the limb with a splint to prevent movement
Together, these steps help slow the movement of venom through the body.
Unlike treatments designed to remove venom, the pressure immobilisation technique works by slowing its spread.
Why the Pressure Immobilisation Technique Works
Many venoms, including those from Australian snakes and some marine animals, spread through the lymphatic system rather than immediately entering the bloodstream.
The lymphatic system moves fluid slowly through vessels located in body tissues.
Unlike blood circulation, which is pumped by the heart, lymph movement relies heavily on muscle activity and movement.
When someone moves the affected limb, muscle contractions push lymph through the vessels and can speed up the spread of venom.
Applying pressure with a bandage compresses lymph vessels and slows this movement.
Immobilising the limb prevents muscle activity from pumping venom through the lymphatic system.
This combination can significantly delay venom circulation until medical care is available.
When the Pressure Immobilisation Technique Is Used
Pressure immobilisation is recommended for bites and stings where venom affects the nervous system and spreads through lymphatic pathways.
Examples include:
• snake bites
• funnel web spider bites
• blue-ringed octopus bites
• cone shell stings
These venoms can cause serious symptoms if they spread quickly through the body.
Slowing the spread of venom is the goal of first aid.
When Pressure Immobilisation Should NOT Be Used
The pressure immobilisation technique is not used for every bite or sting.
For example, some bites and stings cause significant local tissue damage rather than spreading venom through the lymphatic system.
In these cases, tightly bandaging the limb could worsen tissue injury.
This is why correct identification of the type of bite or sting and following current first aid guidelines is important.
First aid training helps people understand when to use pressure immobilisation and when another response is more appropriate.
How to Apply the Pressure Immobilisation Technique
If a venomous bite or sting is suspected, the general steps are:
Keep the person calm and still.
Call emergency services.
Apply a firm bandage directly over the bite area.
Continue bandaging up the entire limb from the fingers or toes upward.
Immobilise the limb with a splint if possible.
Keep the person as still as possible until medical help arrives.
The bandage should be firm but not so tight that it cuts off blood circulation.
The goal is pressure on the tissues, not a tourniquet.
Why the Person Should Remain Still
Movement can significantly increase the speed at which venom spreads through the lymphatic system.
Walking, moving the limb, or unnecessary activity can pump venom through the body more quickly.
Keeping the person still and immobilising the limb helps slow venom movement.
This delay can provide valuable time for emergency services to arrive and for hospital treatment to begin.
Common First Aid Mistakes After a Snakebite
Some traditional or movie-style treatments can actually increase the risk of harm.
Avoid:
• washing the bite area
• cutting the wound
• attempting to suck out venom
• applying a tourniquet
• applying ice
Washing the bite area can remove traces of venom that hospitals may use to identify the species involved.
Learn the Correct First Aid Response
Understanding why first aid techniques work helps people respond more confidently in real emergencies.
At REACHAU, First Aid training focuses on both the skills and the reasoning behind them, helping people stay calm and make better decisions when emergencies occur.
Our nationally recognised courses include training in managing envenomation and other life-threatening emergencies.
Courses include:
Visit https://reachau.com.au to view upcoming courses and training locations.
Frequently Asked Questions
What does the pressure immobilisation technique do?
The pressure immobilisation technique slows the spread of venom through the lymphatic system by compressing lymph vessels and preventing movement of the affected limb.
How tight should the bandage be?
The bandage should be firm and similar in pressure to a bandage used for a sprained ankle. It should not stop blood flow.
Should the bandage be removed once applied?
No. The bandage should remain in place until medical professionals remove it in a controlled environment.
Why is pressure immobilisation used in Australia?
Many Australian venomous animals produce venoms that spread through lymphatic pathways. Slowing lymph movement helps delay venom circulation.
