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  1. Clinical Emergency
  2. How to use the VAPAGuide

How to use the VAPAGuide

Framework of the VAPAGuide strategy

emergency assessment & supportive emergency treatment

  • Collecting key information about an illness or injury in a standardised way using the SAMPLE approach, such as exploring acute signs and symptoms and asking about allergies and medications.

  • Employing the ABCDE approach applicable to all medical emergencies. This includes clearing blocked airways, providing respiratory support if a patient stops breathing and administering cardiovascular treatment if circulation or heart function fails, etc.. 

    Comprehensive ABCDE approach
    ICRC Basic Emergency Care: approach to the acutely ill and injured

Specific therapeutics

  • Antivenoms and antidotes are essential for treating envenoming and poisoning. They are particularly indispensable when the effects of venoms and poisons cannot be managed at all, or not effectively, with supportive therapy alone (e.g. unclottable blood and bleeding in snakebite envenoming). 
    Some effects of venoms and poisons can still be managed with supportive treatment if no antivenom is available or fails (e.g. respiratory failure due to venom-induced disabeling of the neuromuscular junction).
  • Specific therapeutics' require identification of the culprit. 
    In most cases of envenoming, the culprit has not been seen at all, has only been seen vaguely, has not been reliably identified, or has not been perceived as a threat.  
    In cases where only monospecific antivenoms are available, selecting the correct antivenom can be challenging. A high degree of certainty must be achieved in identifying the culprit using indirect evidence.
    If polyspecific antivenoms covering the main culprits in a given region are available, it is less demanding.

SCENARIO 1

The culprit has not or only vaguely been seen, not reliably identified or not been perceived as a threat.

This is the most common scenario when venomous animals and humans share an ecosystem.
Accidents can happen at work, at home and at any time of day or night. Since the culprit has not been seen or has only been vaguely seen, has not been reliably identified or perceived as a threat in >90% of accidents, indirect methods must be used to identify the culprit so that specific treatment can be selected and applied and supportive treatment can be planned.

Let us take a snakebite on the Indian subcontinent as an example.

  • The first step would naturally be to identify the species of snake prevalent in the region where the accident occurred.
  • The second step would be to consider the circumstances of the bite and the behaviour of the snake, as these may provide clues.
  • The third step would be taken if the patient exhibits signs and symptoms of envenoming. The pattern and progression of the clinical features (the effects of the venom) provide further clues as to the identity of the snake.


What tools does the VAPAGuide offer to help identify the culprit indirectly?

We will guide you through these tools, focusing on a krait (Bungarus sp.) as a possible cause of envenoming, and highlight ways to rule out other possibilities.

Set of biological tools

Distribution 

 

Biological features

Set of clinical tools

Emergency Flowcharts

The emergency flowcharts help to identify the cause of envenoming based on the presenting clinical signs and symptoms (as in the clinical flowcharts below), and guide immediate emergency medical responses, including specific therapies such as antivenoms. The flowchart includes sections on neurotoxic signs and symptoms, which are prevalent in krait (Bungarus sp.) envenoming.

Clinical Flowcharts

Clinical flowcharts illustrate how signs and symptoms in the various categories of venom effects evolve over time, ultimately leading to organ failure. For example, respiratory failure can be caused by neurotoxic venom effects. The focus here is again on the krait (Bungarus sp.) as a possible cause of envenoming with neurotoxic signs and symptoms. However, other neurotoxic snakes in the region need to be considered. If significant local signs and symptoms are observed simultaneously, a cobra (Naja sp.) or king cobra (Ophiophagus sp.) is the most likely culprit, whereas if bleeding occurs simultaneously, it is most likely to be a Russell's viper (Daboia russelli).

Clinical management

Clinical management provides key questions and guidance on the main diagnostic and therapeutic steps (both supportive and specific) for caring for an envenomed patient in your region/country.

SCENARIO 2

The culprit is known (name of Genus / species) 

go to ‘Search for Animal Names’

The culprit is available for identification

go to ‘Snake available' ‘Morphological Identification’

In both approaches, this leads you to the

'Clinical Entries' sections of the 'Biomedical Database'

The 'Clinical Entries' sections provide diagnostic and therapeutic advice at species level (in the example: ‘Clinic: Bungarus sp.).

Which diagnostic and therapeutic guidance is provided?

  • The VAPA Guide provides the key clinical features and necessary emergency medical responses to envenoming and poisoning worldwide.
  • It is not a textbook on emergency medicine. It assumes solid clinical knowledge and skills. Links to the SAMPLE and ABCDE approaches are provided, but other reliable sources of emergency medicine can also be used.
  • Specific therapeutics: antivenoms and antidotes. 
    A multitude of antivenoms are produced to varying standards. The quality and accessibility of antivenoms that meet appropriate standards varies widely around the world.
    Great efforts are being undertaken to secure appropriate standards (GMP) and access for people in need. 
    WHO: Snakebite envenoming - A strategy for prevention and control
    WHO: Antivenoms
    WHO Snakebite Information and Data Platform 
  • The VAPAGuide does not provide a comprehensive list of the antivenoms available at a national or regional level, nor does it assess their quality or effectiveness. This would be impossible in such a fluid market. 
    The VAPAGuide refers to WHO-approved antivenoms (see above). 
    Antivenoms that are not manufactured to GMP standards or approved by the WHO are used at the attending physician's discretion and responsibility.

Classification of clinical envenoming and poisoning patterns.

We adopted a toxinological approach, relating observable clinical effects to the pathophysiology of envenoming and the primary targets of venoms and poisons in humans.

The following effects were considered:

  • Autopharmacological effects
  • Local effects
  • Haematological effects
  • Neurological effects
  • Muscular effects
  • Cardiac effects
  • Renal effects

This categorisation attempts to distinguish between the primary and secondary effects of venoms and poisons. The primary effects of venom components can inform supportive therapeutic options and immediate life-saving interventions apart from antivenom therapy. And, also, when combined into envenoming patterns, venom effects help identifying a culprit that has not been (clearly) recognized.
This is straightforward in some cases and more challenging in others. For instance, the effects on the neuromuscular junction (i.e. interference with acetylcholine-based neurotransmission) are unambiguous. The subsequent clinical effects — muscular paralysis (including that of the respiratory muscles) leading to respiratory failure — are clearly primary. 
In the case of other venom effects, distinguishing between primary and secondary effects is less clear-cut; the latter being the common final pathway when organ systems fail. Furthermore, the complex mixtures of active substances in venoms in many venomous and poisonous animals still need to be better understood.