Most snakes are harmless to humans, but some are venomous. A venomous snake injects venom through its fangs and the bite can be life-threatening. If possible, identifying the type of snake will help medical professionals determine whether the snake is venomous, the type of venom it produces and therefore the best way to help the person who has been bitten.
Guidelines
- Limb injuries should be kept still as much as possible to slow the spread of venom. It may be helpful to immobilise the limb by applying a non-elastic bandage (or using clean clothing such as trousers or shirt). *
- If they are properly trained to do so, first aid providers may use the pressure immobilisation technique, by firmly applying a cotton or rubber pad under a non-elastic bandage for special situations such as remote locations and wilderness environments. *
- A tourniquet should not be applied to snake envenomation because it may not be effective and may result in an extended hospital stay. *
Good practice points
- The person should limit physical activity to prevent the spread of toxins. If the bite is on the person’s leg, they should not walk on the immobilised leg unless no other option is available.
- It is reasonable to keep the injured area at or lower than the level of the heart.
- It is reasonable to remove jewellery, watches or tight clothing to prevent blood flow being restricted if there is swelling.
- In areas with limited resources (e.g., a wilderness or remote environment with longer wait times to EMS), it is reasonable to wash the wound.
- Suction should not be applied to a snakebite because it does not allow complete removal of the venom and it might aggravate the damage to the skin.
- A cold compress should not be applied to a snakebite because this may cause the blood vessels to contract and make the venom spread more quickly through the body.
- The wound should not be rubbed as this may cause the venom to spread more quickly through the body.
- Cutting the wound with a knife to increase bleeding is not recommended. It does not reduce the effect of the venom and aggravates the injury.
Chain of survival behaviours
Prevent and prepare
- Wear appropriate footwear in areas snakes are present.
- Know how to identify local snakes and whether they are venomous.
- Keep away from snakes that you encounter, trying not to disturb them. Do not kill or injure them.
Early recognition
A person with a snakebite may:
- be in pain
- have a visible bite mark
- experience swelling or discolouration of the skin around the area of the bite.
A venomous snake may also cause:
- thirst
- nausea and vomiting
- blurred or double vision
- sensory disturbances or paralysis
- sweating and excessive production of saliva
- a sudden drop in blood pressure, leading to Shock
- Seizures.
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NOTE
If possible and safe to do so, identify the type of snake that bit the person. Do not try to catch the snake. Consider taking a photo or make note of its features for a medical professional to identify.
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First aid steps
- Help the person to lie down in a comfortable position. Advise them to move as little as possible.
- Access emergency medical services (EMS).
- Remove jewellery, watches or tight clothing to prevent blood flow being restricted if there is swelling. Do this while moving the limb as little as possible.
- Monitor the person’s level of response and breathing. Encourage them to remain as still as possible.
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CAUTION
The following actions are not effective and may even cause further harm:
- applying a tourniquet
- sucking out the venom
- applying a cold compress
- rubbing the bite
- cutting the wound with a knife to increase bleeding.
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Local adaptations
- If in an area with limited resources (e.g., a wilderness or remote environment with longer wait times to EMS) immobilise the limb with a non-elastic bandage to reduce the spread of the venom. If a non-elastic bandage is not available, use clothing such as trousers or a shirt.
- If in an area with limited resources (e.g., a wilderness or remote environment with longer wait times to EMS) wash the wound with potable (clean) water and apply a non-elastic bandage to reduce the risk of infection. See Cuts and grazes.
- If necessary, carry the person, for example by making a stretcher or by two people linking their arms to make a chair for the person.
Access help
- It is important to tell medical professionals about the type of snake that bit the person. This will help them provide the best care quickly to the person.
Education considerations
Context considerations
- Contact the local biological centre to find out the types of snakes in the region, whether they are venomous, where to get antivenom and any recommended treatment specific to the types of local snakes.
- Include education on first aid for snakebites in regions where venomous snakes are found or for learners travelling to areas with exotic or venomous snakes.
- Specially trained first aid providers may use the pressure immobilisation technique in special situations such as remote locations and wilderness environments. Ensure adequate guidance and practise of this technique as there is evidence it is often applied with poor outcomes, even by those with specific training. Be clear the technique should only be used in special circumstances.
Learner considerations
- For learners who might be visiting an area where there are snakes, emphasise the importance of research to know what snakes are present and how to avoid them, as well as action to take if bitten.
- For communities who live in places where there are snakes, prevention strategies tend to be well known but first aid treatment seems less well known. Public campaigns to publicise snakebite first aid (immobilisation of the bitten area and loosening restrictive clothing) could be effective (Alcoba et al., 2020).
Facilitation tips and tools
- Introduce this topic with a focus on prevention.
- Emphasise the importance of getting treatment quickly – even if the snake is not venomous, the bite can quickly become infected.
- Use pictures of the most common snakes in the region to increase learners’ ability to identify snakes and raise awareness of the danger.
- Use pictures of the signs and symptoms to help learners to understand the seriousness of snakebites.
- Emphasise that people should not try to catch or kill a snake.
- Dispel myths about snakebite if they are prevalent among the learner audience:
> Do not cut the bite with a knife.
> Do not use a tourniquet.
> Do not suck the bite.
Scientific foundation
Systematic reviews
We used four evidence summaries from the Centre for Evidence-based Practice (CEBaP) for the following topics: pressure immobilisation; tourniquet; cryotherapy and suction for snakebite. CEBaP searches on irrigation or washing a snakebite, and on the application of ice on a snakebite found no relevant studies.
Pressure immobilisation
Pressure immobilisation is a technique that can be achieved in several ways: by using an elastic bandage (applying pressure uniformly around and along the limb), or by firmly applying a cotton or rubber pad under a non-elastic bandage (pressure applied specifically to the injection site, with sufficient firmness). However, these techniques are not easy to be performed by first aid providers, and therefore an evidence summary concerning the feasibility of applying this technique was also developed. (CEBaP, 2019)
Elastic bandage and splint
There is limited evidence from two experimental studies neither in favour of using an elastic bandage and splint nor of using the control (no first aid treatment). A statistically significant decrease of speed of venom spread, using elastic bandage and splint compared to no first aid treatment, could not be demonstrated in two studies. Evidence is of very low certainty and results of these studies are imprecise due to limited sample size and/or large variability of the results (CEBaP, 2019).
Elastic bandage and splint, combined with rest
There is limited evidence from one experimental study in favour of rest with an elastic bandage and splint. It was shown that using an elastic bandage and splint, in combination with rest, resulted in a statistically significant decrease of transit of mock venom, compared to the same treatment while walking. Evidence is of very low certainty and results cannot be considered precise due to limited sample size and/or large variability of results (CEBaP, 2019).
Firm cloth or rubber pad held in place by non-elastic bandage at a certain pressure
There is limited evidence from four experimental studies in favour of using a firm pad (e.g. a cotton cloth, or a rubber pad), held in place with a broad non-elastic bandage under a minimum pressure of 60-70 mmHg. It was shown that using such a pad resulted in a statistically significant decrease of speed of venom spread or transit of mock venom, compared to no treatment. Evidence is of very low certainty and results cannot be considered precise due to limited sample size and/or large variability of results (CEBaP, 2019).
Feasibility of applying pressure immobilisation by lay first aid providers
There is limited evidence from two experimental studies in favour of training first aid providers to apply an elastic bandage. It was shown that training resulted in a statistically significant increase of bandage application with optimal pressure range, compared to written instructions. However, it was shown that first aid provider volunteers did not succeed in a statistically significant higher correct bandage application or achievement of correct pressure, compared to medical volunteers. Evidence is of low certainty and results cannot be considered precise due to limited sample size and large variability of results (CEBaP, 2019).
Tourniquet
There is limited evidence from seven observational studies in favour of not using a tourniquet. It was shown that using a tourniquet resulted in an increase in local swelling, the amount of antivenom required, duration of hospital stay and severity of local envenomation, compared to not using a tourniquet. A statistically significant increase in haemorrhagic syndrome, amount of antivenom required, acute renal failure, acute respiratory failure, death, death or disability, local oedema, envenoming, duration of hospital stay, tissue necrosis, serum venom level before antivenom treatment and incidence of multiple organ dysfunction syndrome, when using a tourniquet, compared to not using a tourniquet, could not be demonstrated. On the other hand, it was shown in another study that using a tourniquet resulted in a statistically significant decrease in the amount of antivenom required, compared to not using a tourniquet. Evidence is of very low certainty and results cannot be considered precise due to limited sample sizes, low number of events and large variability of results (CEBaP, 2019).
Suction
There is limited evidence from one observational study neither in favour of using suction nor not using suction. A statistically significant decrease of deaths or disability, the amount of antivenom required or duration of hospital stay, using suction compared to no first aid, could not be demonstrated. Evidence is of very low certainty and results of this study are imprecise due to the limited sample size, the low number of events and large variability of results or lack of data (CEBaP, 2019).
Education review
We found one paper to embellish educational insight on this topic. Alcoba et al. (2020) conducted a cross-sectional multi-cluster household survey in the Akonolinga health district of Cameroon and found an incidence of 665 snakebites per 100,000 inhabitants in one year. Despite good community knowledge of preventative measures, the researchers found that resulting fatalities, acute complications and chronic disability were associated with consulting traditional healers. Only 3% of people bitten by a snake received antivenom treatment. The authors concluded that there was an urgent need for first aid training for traditional healers and health professionals.
References
Systematic reviews
Centre for Evidence-Based Practice, Belgian Red Cross-Flanders. (2019). Evidence summary Snake bite – Ice. Available from: https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice, Belgian Red Cross-Flanders. (2019). Evidence summary Snake bite – Rinsing the venom. Available from:
https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice, Belgian Red Cross-Flanders. (2019). Evidence summary Snake bite – Suction. Available from:
https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice, Belgian Red Cross-Flanders. (2019). Evidence summary Snake bite – Tourniquet. Available from:
https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Centre for Evidence-Based Practice, Belgian Red Cross-Flanders. (2019). Evidence summary Snake bite – Pressure immobilisation. Available from: https://www.cebap.org/knowledge-dissemination/first-aid-evidence-summaries/
Education references
Alcoba, G., Chabloz, M., Eyong, J., Wanda, F., Ochoa, C., Comte, E., … & Chappuis, F. (2020). Snakebite epidemiology and health-seeking behavior in Akonolinga health district, Cameroon: Cross-sectional study. PLoS neglected tropical diseases, 14(6), e0008334. Full article https://journals.plos.org/plosntds/article?id=10.1371/journal.pntd.0008334&rev=1
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