How should I manage a patient who presents within one hour of acute paraquat ingestion?

Management of Acute Paraquat Poisoning Within One Hour of Ingestion

Immediately remove all contaminated clothing, perform thorough skin decontamination with soap and water, administer activated charcoal (15-20g) after securing the airway, and strictly limit oxygen supplementation to maintain SpO2 between 85-88% only if it falls below 85%. 1, 2, 3

Immediate Decontamination (First Priority)

External Decontamination

• Remove all contaminated clothing and jewelry immediately to prevent continued dermal absorption, as this is a critical first step that directly impacts toxin load 1, 2
• Thoroughly wash all exposed skin areas with soap and water using warmed water at lower pressure to prevent hypothermia 1
• Healthcare workers must wear appropriate personal protective equipment including gloves and protective clothing when handling the patient or contaminated materials 2

Gastrointestinal Decontamination

• Administer activated charcoal (15-20g) or Fuller's earth as the preferred decontamination method rather than gastric lavage, as these agents work through adsorption of the toxin 1
• The American College of Medical Toxicology specifically recommends against routine gastric lavage for paraquat poisoning 1
• Only perform gastrointestinal decontamination after securing the airway and achieving hemodynamic stability, as aspiration risk is significant 1
• Consider multiple-dose activated charcoal (15-20g every 6 hours) after initial dose 1

Critical Pitfall: Do not delay airway protection to perform gastrointestinal decontamination—airway security takes absolute precedence 1

Oxygen Management (Uniquely Important in Paraquat)

Restrictive Oxygen Strategy

• Target oxygen saturation of 85-88%, which is dramatically lower than typical critical care targets 2, 3
• Only administer supplemental oxygen if SpO2 falls below 85% 1, 2, 3
• Reduce or stop oxygen therapy if saturation rises above 88% 2, 3
• Supplemental oxygen dramatically worsens paraquat toxicity by increasing free radical production and accelerating lung injury through enhanced oxidative stress 1, 3

Critical Pitfall: Do not provide supplemental oxygen liberally as you would in other poisonings—this is uniquely harmful in paraquat toxicity and represents a common management error 1

Supportive Care and Monitoring

Immediate Actions

• Contact poison control center immediately for expert guidance and maintain continuous contact for evolving recommendations 1, 2
• Provide standard airway management if respiratory distress develops 2
• Treat hypotension and dysrhythmias according to standard protocols 2
• Administer benzodiazepines for seizures or severe agitation if they occur 2

Monitoring Parameters

• Maintain continuous oxygen saturation monitoring with strict adherence to 85-88% target 3
• Monitor renal function, hepatic function, and acid-base status, as metabolic acidosis and altered organ function at presentation are associated with significantly higher mortality 4

Additional Treatment Considerations

Extracorporeal Therapies

• Hemoperfusion may improve survival when available and should be considered early, as one study showed 36% survival in patients who received hemoperfusion compared to those who did not 4
• Renal replacement therapy may be needed for acute kidney injury but has not shown independent mortality benefit 4

Immunosuppression

• While no specific antidote exists for paraquat, some evidence suggests methylprednisolone (500mg daily for 5 days) may provide survival benefit, though this is based on case reports and observational data 5, 4
• Antioxidants including N-acetylcysteine and vitamin E have been used in case reports with variable success 6

Prognostic Factors

Duration of presentation is the most critical modifiable factor—patients who survived presented significantly earlier (median 14 hours) compared to those who died (median 48 hours) 4. Within the one-hour window described in this question, you have the optimal opportunity to impact outcome through aggressive decontamination.

Other poor prognostic indicators at presentation include metabolic acidosis, altered renal function, and altered hepatic function 4. Age, gender, and occupation do not significantly correlate with mortality 4.

The mortality rate for paraquat poisoning remains extremely high (88% in recent studies) despite optimal management, emphasizing the critical importance of prevention and immediate aggressive treatment 4, 7.