Is gastric lavage indicated in chlorpyrifos (Celphos) or other organophosphate poisoning?

Gastric Lavage in Organophosphate Poisoning: Not Recommended

Gastric lavage should NOT be routinely performed in chlorpyrifos (Celphos) or other organophosphate poisoning, as it poses significant risk to healthcare workers from secondary exposure and has no proven benefit in improving clinical outcomes. 1, 2

Why Gastric Lavage Is Not Recommended

Lack of Clinical Benefit

• The American Academy of Clinical Toxicology and European Association of Poisons Centres state that gastric lavage should not be employed routinely in poisoned patients, as there is no certain evidence that its use improves clinical outcome and it may cause significant morbidity 2
• Even when performed within 60 minutes of ingestion for potentially life-threatening amounts, clinical benefit has not been confirmed in controlled studies 2
• In experimental studies, the amount of toxin removed by gastric lavage was highly variable and diminished rapidly with time 2

Serious Risk of Secondary Exposure to Healthcare Workers

• Healthcare workers performing gastric lavage are at significant risk of secondary exposure from gastric contents and emesis containing organophosphates, with documented cases requiring atropine, pralidoxime, and even intubation for 24 hours 1
• Personal protective equipment is mandatory when handling contaminated gastric contents, as failure to use PPE has resulted in severe illness in healthcare workers 1
• Never allow healthcare workers to handle gastric contents without PPE, as organophosphates in emesis and gastric aspirate can cause severe secondary poisoning 1

Limited Therapeutic Window

• Gastric lavage should not be considered unless the procedure can be undertaken within 60 minutes of ingestion, and even then benefit is unproven 2
• The evidence table from ethylene glycol poisoning (which included organophosphate data) showed gastric lavage was performed in only 47 of 446 cases, suggesting limited real-world utility 3

What Should Be Done Instead

Immediate Decontamination (External Only)

• Remove all contaminated clothing immediately and irrigate the skin thoroughly with soap and water; brush off any powdered chemicals with a gloved hand before irrigation 1
• Ensure proper personal protective equipment (PPE) when caring for patients with organophosphate exposure to prevent contamination of caregivers 1

Avoid Oral Interventions

• Do NOT perform gastric lavage or give activated charcoal unless specifically directed by poison-control services 1
• Avoid giving anything by mouth (e.g., water, milk, activated charcoal) unless explicitly instructed by poison-control personnel, as oral administration can provoke emesis and aspiration without proven benefit 1

Focus on Life-Saving Antidotal Therapy

The priority is immediate pharmacologic treatment, not gastrointestinal decontamination:

Atropine (First-Line, Class 1 Recommendation):

• Adults: 1–2 mg IV immediately, doubling every 5 minutes until bronchorrhea, bronchospasm, and bradycardia resolve 1
• Children: 0.02 mg/kg IV (minimum 0.1 mg, maximum 0.5 mg per dose), doubling every 5 minutes 1
• Typical cumulative requirements: 10–20 mg in first 2–3 hours, some patients need up to 50 mg in 24 hours 1

Pralidoxime (Class 2a Recommendation, Level A Evidence):

• Adults: 1–2 g IV loading dose over 15–30 minutes, followed by continuous infusion of 400–600 mg/hour 1
• Children: 25–50 mg/kg IV loading dose (maximum 2 g) over 15–30 minutes, followed by 10–20 mg/kg/hour continuous infusion 1
• Must be given early before enzyme "aging" occurs (within minutes to hours depending on the specific organophosphate) 1

Benzodiazepines for Seizures:

• Diazepam 0.2 mg/kg IV or midazolam 0.05–0.1 mg/kg IV 1

Early Airway Management:

• Early endotracheal intubation for life-threatening poisoning 1
• Avoid succinylcholine and mivacurium (contraindicated as they are metabolized by cholinesterase) 1

Special Exception: Granular Formulations

The only scenario where prolonged gastrointestinal decontamination might be considered is with granular organophosphate formulations (like granular disulfoton), where delayed absorption from residual granules in the stomach can cause secondary elevation of plasma concentrations 20–56 hours after ingestion 4. However, this requires:

• Repetitive or prolonged gastric and intestinal lavage 4
• Activated charcoal 4
• Continuous intravenous infusion of pralidoxime in addition to atropine 4
• Strict PPE protocols to protect healthcare workers 1

Critical Pitfalls to Avoid

• Never delay antidotal therapy (atropine, pralidoxime, benzodiazepines) to perform gastric lavage 1, 2
• Never perform gastric lavage without full PPE for all healthcare workers involved 1
• Never rely on gastric lavage as a substitute for aggressive pharmacologic treatment 1, 2
• Gastric lavage is contraindicated if airway protective reflexes are lost unless the patient is intubated 2