Is gastric lavage recommended for paraquat poisoning?

Gastric Lavage for Paraquat Poisoning

Gastric lavage is NOT recommended as a routine decontamination method for paraquat poisoning; instead, multiple-dose activated charcoal (15-20g every 6 hours) should be considered only after airway protection and hemodynamic stabilization. 1

Why Gastric Lavage Should Be Avoided

Current guidelines explicitly recommend against routine gastric lavage for poisoning cases, including paraquat. 2 The evidence shows that:

• Activated charcoal or Fuller's earth are the preferred decontamination agents rather than mechanical gastric lavage, as they work through adsorption of the toxin rather than physical removal 1, 3
• Gastric lavage should only be considered in the earliest phases (within hours) of mushroom poisoning as an example of when it might have utility, but this is not standard for paraquat 4
• The critical window for any gastrointestinal decontamination is extremely narrow, and mechanical lavage has not been shown to improve survival in paraquat poisoning 5

Recommended Decontamination Approach

The priority is activated charcoal or Fuller's earth, NOT gastric lavage:

• Remove contaminated clothing immediately and thoroughly wash exposed skin to prevent continued dermal absorption 1, 6
• Consider multiple-dose activated charcoal (15-20g every 6 hours) only after securing the airway and achieving hemodynamic stability 1
• Fuller's earth, activated charcoal, and resins may prevent some absorption but must be given very early 3
• Never attempt decontamination without first ensuring airway protection, as aspiration risk is significant 2

Critical Management Priorities Beyond Decontamination

The evidence strongly indicates that decontamination methods (whether lavage or charcoal) have limited impact on survival, which depends primarily on the amount ingested 5:

Oxygen Management - The Most Critical Intervention

• Avoid supplemental oxygen unless SpO2 falls below 85%, and reduce or stop oxygen if saturation rises above 88% 1, 6
• Target oxygen saturation of 85-88% because paraquat toxicity is dramatically worsened by high oxygen concentrations through increased free radical production 1, 6
• This is counterintuitive but evidence-based: oxygen accelerates paraquat-induced lung injury 1

Prognostic Indicators

The following factors determine outcome far more than decontamination method 5:

• Plasma paraquat concentration within first 24 hours (survival likely if ≤2.0 mg/L at 4h, ≤0.6 mg/L at 6h, ≤0.3 mg/L at 10h)
• Amount ingested (>50 mg/kg is almost universally fatal within 72 hours; 35-50 mg/kg causes delayed death from pulmonary fibrosis)
• Absence of caustic burns in the upper digestive tract indicates better prognosis
• Route of exposure (inhalation/dermal has much better prognosis than ingestion)

Additional Treatment Considerations

• Contact poison control centers immediately for expert guidance 6
• Hemoperfusion or hemodialysis may be attempted for massive ingestions but have not clearly improved survival rates 3, 5
• Immunosuppressive therapy (steroids and cyclophosphamide) should be considered, though evidence is limited 7
• Antioxidant therapy including deferoxamine (100 mg/kg/24h) and continuous acetylcysteine infusion (300 mg/kg/day for 3 weeks) may be beneficial when combined with early decontamination 8

Common Pitfalls to Avoid

• Do not delay airway protection to perform gastrointestinal decontamination 2
• Do not provide supplemental oxygen liberally as you would in other poisonings—this is uniquely harmful in paraquat toxicity 1, 6
• Do not rely on decontamination alone—the amount ingested determines outcome more than any treatment intervention 5
• Do not use gastric lavage routinely when activated charcoal is the evidence-based alternative 1, 2