What is the treatment for a patient with paraquat poisoning?

Treatment of Paraquat Poisoning

Immediately remove all contaminated clothing, thoroughly wash exposed skin, avoid supplemental oxygen unless SpO2 falls below 85%, contact poison control immediately, and consider multiple-dose activated charcoal only after airway protection—gastric lavage is not routinely recommended. 1, 2, 3

Critical Initial Actions

Rescuer and Healthcare Worker Safety

• Wear protective clothing and gloves when handling the patient, contaminated materials, or body fluids (including vomit) to prevent secondary exposure. 1, 3
• Healthcare workers must use appropriate personal protective equipment throughout patient care. 1

Immediate Decontamination

• Remove all contaminated clothing and jewelry immediately to prevent continued dermal absorption. 1, 2
• Thoroughly wash all exposed skin areas with soap and water. 1, 3
• In pediatric patients, use warmed shower water at lower pressure with heat lamps and blankets to prevent hypothermia during decontamination. 2

Expert Consultation

• Contact poison control centers immediately for expert guidance and maintain continuous contact for evolving treatment recommendations. 1, 2, 3

Gastrointestinal Decontamination

What NOT to Do

• Do not perform routine gastric lavage—this is not standard practice for paraquat poisoning. 2, 4
• Gastric lavage should not be performed as it provides no clear benefit and delays more effective interventions. 4

Preferred Decontamination Method

• Administer multiple-dose activated charcoal (15-20g every 6 hours) or Fuller's earth ONLY after securing the airway and achieving hemodynamic stability. 2, 3, 5, 4
• Activated charcoal and Fuller's earth work through adsorption of the toxin and may prevent some absorption. 2, 5
• Never attempt decontamination without first ensuring airway protection due to significant aspiration risk. 2

Oxygen Management: The Most Critical Pitfall to Avoid

Unique Oxygen Targets

• Administer supplemental oxygen ONLY if oxygen saturation falls below 85%. 1, 2, 3
• Target oxygen saturation of 85-88%—significantly lower than typical critical care targets. 1, 2, 3
• Reduce or stop oxygen therapy if saturation rises above 88%. 1, 2, 3

Rationale for Restrictive Oxygen Use

• Supplemental oxygen dramatically worsens paraquat toxicity by accelerating paraquat-induced lung injury through increased free radical production and lipid peroxidation. 1, 2, 3
• Paraquat generates reactive oxygen species that cause cellular damage via lipid peroxidation, and high oxygen concentrations amplify this mechanism. 4
• This is the most important deviation from standard critical care practice and a common fatal error. 1, 2

Supportive Care

Standard Interventions

• Provide standard airway management if respiratory distress develops. 1, 3
• Treat hypotension and dysrhythmias according to standard protocols. 1, 3
• Administer benzodiazepines for seizures or severe agitation if they occur. 1
• Focus on correction of metabolic derangements. 3

Extracorporeal Treatments

Limited Efficacy

• Hemodialysis and hemoperfusion have been attempted but show no clear improvement in survival rates. 5, 4
• These elimination methods are unlikely to change the clinical course because paraquat is rapidly distributed into tissues within 12-24 hours. 4
• One case series reported favorable outcomes with daily conventional hemodialysis combined with immunosuppression, but this represents very weak evidence. 6

Immunosuppression and Antioxidants

Widely Practiced but Unproven

• Immunosuppression with dexamethasone, cyclophosphamide, and methylprednisolone is widely practiced but evidence for efficacy is very weak. 4
• Antioxidants such as N-acetylcysteine might be beneficial through free radical scavenging and anti-inflammatory actions, but there are no published human trials demonstrating efficacy. 5, 4
• The case fatality remains very high in all centers despite large variations in treatment approaches. 4

Prognosis

Key Prognostic Indicators

• The most important prognostic indicator is the quantity of paraquat absorbed, as shown by plasma paraquat concentration. 5
• Plasma paraquat concentrations, urine and plasma dithionite tests, and clinical features provide a good guide to prognosis. 4
• The absence of caustic burns in the upper digestive tract indicates a better prognosis. 5
• Death usually occurs within 2 days of ingestion of 50 mg/kg, though at lower doses death may be delayed for several weeks. 5

Common Pitfalls

• Do not delay airway protection to perform gastrointestinal decontamination. 2
• Do not provide supplemental oxygen liberally—this is uniquely harmful in paraquat toxicity. 2, 3
• Do not use gastric lavage routinely when activated charcoal is the evidence-based alternative. 2, 4
• Do not assume renal failure alone indicates a fatal outcome, though it develops in the majority of patients who eventually die. 5