Pressure immobilisation technique

Pressure immobilisation technique (PIT) is a first aid technique used in the management of bites and stings from venomous creatures, such as snakes, spiders, and jellyfish. The technique involves the application of a bandage over the bite site and then immobilising the limb or affected area to slow the spread of venom through the lymphatic system. The goal of PIT is to delay the systemic absorption of venom, thereby buying time for the victim to reach medical care and receive appropriate antivenom treatment.

Principles

The pressure immobilisation technique is based on the principle that venom from bites and stings primarily moves through the lymphatic system, rather than the blood circulatory system. By applying pressure to the affected limb and immobilising it, the technique aims to reduce lymphatic flow and prevent the venom from spreading throughout the body. This method is particularly recommended for neurotoxic envenomations, where venom affects the nervous system, such as those from certain species of snakes and the box jellyfish (Chironex fleckeri).

Application

To effectively apply the pressure immobilisation technique, the following steps should be followed:

1. Apply a broad pressure bandage directly over the bite site as soon as possible. The bandage should be as tight as one would apply to a sprained ankle.
2. Extend the bandage both up and down the limb to cover as much of the affected area as possible.
3. Immobilise the limb using a splint or another rigid object to prevent movement.
4. Ensure the patient remains as still as possible and seek medical assistance immediately.

It is important to note that PIT is not recommended for bites from certain creatures, such as spiders in the U.S. (e.g., the black widow and brown recluse), where compression could worsen the condition.

Effectiveness

The effectiveness of the pressure immobilisation technique has been supported by various studies, particularly for snakebites. However, its efficacy can depend on the type of venom and the promptness of application. Incorrect application of the technique can potentially lead to increased discomfort or complications. Therefore, proper training and education on the application of PIT are crucial.

Controversies and Considerations

While widely taught and recommended, the pressure immobilisation technique has its critics. Some argue that in certain cases, such as with highly cytotoxic venoms (which destroy cells), the technique might concentrate venom in one area, potentially causing more local damage. The technique's effectiveness and appropriateness can vary depending on the species involved and the geographical location.

Conclusion

The pressure immobilisation technique is a valuable first aid procedure for managing envenomations from a variety of venomous creatures. When applied correctly, it can significantly delay the spread of venom, providing crucial time for the victim to receive medical care. However, education and proper training in the technique are essential to ensure its effectiveness and to avoid potential complications.

‎