SAQ 408 – Toxicology – organophosphate poisoning

Toxicology – organophosphate poisoning.

a. Risk assessment

• Agent and formulation.
• Quantity ingested.
• Time since exposure.
• Co-ingestants.
• Patient factors and comorbidities.
• Current features of toxicity.

b. Expected effects

• Cholinergic crisis.
• Muscarinic effects: diarrhoea, urination, miosis, bronchospasm, bronchorrhoea, vomiting, lacrimation, and salivation.
• Nicotinic effects: mydriasis, tachycardia, weakness, hypertension, and fasciculations.

c. Management

• Manage in a well-ventilated area; sophisticated PPE is not usually required after standard decontamination precautions.
• Prioritise airway and breathing, including oxygenation and control of secretions.
• Give atropine for muscarinic toxicity: 1.2 mg IV, doubling every 2 minutes until secretions dry.
• Treat seizures with benzodiazepines, for example midazolam 5 mg IV titrated to effect.
• Give IV normal saline and correct large fluid losses.
• Intubate early if oxygenation or ventilation is not rapidly achieved.
• Discuss pralidoxime with a toxicologist; its role is controversial.