Organophosphate PoisoningICU / resuscitation

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Cholinergic (DUMBELS): salivation, lacrimation, bronchorrhea, miosis

ABCDE

Staff PPE + decontaminate; airway/secretion control; atropine titrated; pralidoxime.

  1. First: Decontaminate skin/clothing
  2. Atropine IV — titrate to dry secretions / clear bronchorrhea
  3. Add: Pralidoxime (2-PAM) — reactivates cholinesterase

Order set

  • Decontaminate (PPE)
  • Atropine titrated to secretions
  • Pralidoxime
  • Airway/secretion management
  • Benzos for seizures

Escalate / ICU

  • Bronchorrhea / respiratory failure
  • Large atropine requirement
  • Seizures / coma

Criteria

AdmitAll symptomatic
ICURespiratory failure, large atropine needs
IntubateBronchorrhoea/respiratory failure
VentilateRespiratory failure
DischargeSecretions dry, stable off atropine, observed for intermediate syndrome

Never

  • Delay intubation in bronchorrhea/respiratory failure or coma — intubate EARLY; AVOID succinylcholine (prolonged paralysis via inhibited pseudocholinesterase) — use rocuronium for RSI
  • Under-dose pralidoxime — 2 g (≥30 mg/kg) IV over 20–30 min, then ≥8 mg/kg/h (≈650 mg/h) infusion, continued ≥24 h after atropine no longer needed (WHO/Eddleston)
Clinical detail — differentials, red flags, pitfalls, disposition
Red flags
  • Bronchorrhoea/respiratory failure
  • Bradycardia
  • Seizures
Differentials
  • Carbamate poisoning
  • Nerve agent
  • Cholinergic crisis
Common mistakes
  • Under-dosing atropine — endpoint = dry chest + HR >80, NOT pupils/miosis
  • Contaminating staff
  • Succinylcholine for RSI (prolonged paralysis) — use rocuronium
  • Missing intermediate syndrome — surveil neck-flexion/respiratory weakness 24–96 h; counsel on delayed polyneuropathy
Disposition & follow-up

ICU; large atropine requirements; observe 24–96 h for intermediate syndrome (neck-flexion/respiratory weakness); counsel on delayed polyneuropathy.

Discharge package
Medications
Follow-upObserve for intermediate syndrome; occupational review
Warning symptomsWeakness, breathing difficulty (days later)
💊 Treatment detail — doses & preparation
Atropineantimuscarinic
DoseBradycardia: 0.5 mg IV q3–5 min (max 3 mg). Organophosphate: 1–2 mg IV bolus, double q5 min until secretions dry, then infusion 10–20% of loading dose/h
Preparation1 mg/mL ampoule undiluted; organophosphate needs many mg — stock 10+ ampoules
MonitorHR, secretions, pupils (not a target in OP); tachycardia, urinary retention
Pralidoximecholinesterase reactivator
Dose2 g (≥30 mg/kg) IV over 20–30 min, then ≥8 mg/kg/h (≈650 mg/h) infusion (or 1 g q1h), continued ≥24 h after atropine no longer needed (WHO/Eddleston)
Preparation1 g vial in 20 mL water, then further dilute for infusion
MonitorGive WITH atropine (atropine first); most effective early before ageing
Lorazepambenzodiazepine
DoseStatus: 0.1 mg/kg IV (max 4 mg/dose), may repeat ×1
Preparation4 mg/mL vial dilute 1:1 with NS; slow push
MonitorRR, SpO₂; flumazenil caution in chronic users
📖 WHO / poisons-centre guidanceReviewed July 2026

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