Diagnosis & Treatment — First aid / lay people
General problems
- Fear,
- collapse, loss of consciousness.
- Calm the patient.
- Place the patient in a stable lateral position, or possibly the Trendelenburg position (shock position).
Anxiety (fear of death) plays an important role following accidents with venomous animals and has an additional negative influence on the clinical course after an accident.
Loss of consciousness after an accident with a venomous animal can have many causes. It is important to place the patient in a stable lateral position to avoid aspiration. If peripheral circulatory failure is present, the shock position may improve the patient's condition. If resuscitation is necessary, it is only in exceptional cases that lay people will be sufficiently well trained to be able to intervene.
How can absorption and circulation of the venom be delayed?
Elapids (Micrurus sp., Micruroides euryxanthus):
- Compression-immobilisation method or comparable methods and splinting of the bitten extremity.
- Avoid pressure points when applying the splint (padding). Transport the patient.
Crotalids:
- Immobilisation of the bitten extremity using a splint (piece of wood or something similar).
- Avoid pressure points when applying the splint (padding). Transport the patient.
The risks of the compression-immobilisation method limit its use to elapid bites (Micrurus fulvius, Micruroides euryxanthus), which are uncommon. Identification of these snakes is simple even for lay people. Micrurus sp. and Micruroides euryxanthus are distinctive due to their typical markings and colouring. Local swelling is minor or absent.
The compression-immobilisation method or comparable methods should not be used for crotalid bites. They intensify the local effects of the venom and result in increased tissue damage (Hardy 1992b). Furthermore progressive swelling underneath a bandage of this type may critically compromise the arterial blood supply.
Average time between the bite and death
Elapids (Micrurus sp): 4–6 h (respiratory failure) (Rosenfeld 1971).
Micrurus fulvius: 8–24 h (respiratory failure) (Willson 1908, McCollough and Gennaro 1970).
Crotalids (rattlesnakes):
- <1 h to several hours (prolonged hypotensive/hypovolaemic shock),
- days (haemostatic or infectious complications) (Dart et al. 1992).
Crotalids (Bothrops asper and Lachesis sp.): several days (Rosenfeld 1971) (these data do not take into account early fatalities due to autopharmacological effects of the venom).