Gastric Lavage is Contraindicated in Zinc Phosphide Ingestion
Do not perform gastric lavage (stomach wash) in zinc phosphide poisoning cases, as this procedure can worsen clinical outcomes and increase phosphine gas exposure to healthcare workers. 1
Why Gastric Lavage Should Be Avoided
The primary concern with zinc phosphide ingestion is the liberation of highly toxic phosphine gas when the compound contacts gastric acid. 2, 3 Gastric lavage poses several critical dangers:
- Increased gas production: Introducing fluid into the stomach accelerates the hydrolysis reaction, generating more phosphine gas 4
- Healthcare worker exposure: The procedure releases phosphine gas into the environment, creating a vapor hazard for medical staff 5
- Aspiration risk: Patients may be obtunded or develop altered mental status, making airway protection during lavage extremely hazardous 3, 6
- Worsening clinical condition: Mechanical manipulation can promote absorption and systemic distribution of the toxin 1
Recommended Decontamination Approach
Instead of gastric lavage, the evidence supports alternative decontamination strategies:
- Do not induce vomiting under any circumstances, as this worsens the clinical condition 1
- Consider polyethylene glycol for whole bowel irrigation if radiopaque material is visible on abdominal X-ray and the patient presents early 7
- Ensure adequate ventilation of the treatment area to prevent phosphine gas accumulation and secondary exposure to staff 5
Critical Clinical Pitfalls
Asymptomatic presentation does not indicate safety. A documented case showed sudden cardiac arrest 19 hours after ingestion in a completely asymptomatic patient with normal vital signs and laboratory tests. 7 This underscores several key points:
- Initial mild gastrointestinal symptoms (nausea, vomiting, abdominal pain) occur in 100% of cases but do not predict severity 4
- Cardiotoxicity can manifest suddenly without warning, even after an apparent latent period 7, 6
- Continuous cardiac monitoring is essential, as myocarditis and sudden cardiac arrest are leading causes of death 3, 7, 6
Essential Supportive Management
Since no antidote exists for zinc phosphide poisoning, treatment focuses on aggressive supportive care: 2, 3
- Airway management: Prepare for rapid intubation, as pulmonary edema and respiratory failure develop quickly 3, 6
- Circulatory support: Anticipate shock, hypotension (40% of cases), and cardiovascular collapse requiring vasopressors 6, 4
- Metabolic correction: Address metabolic acidosis (present in 60% of cases) with appropriate fluid resuscitation 4
- Cardiac monitoring: Check cardiac enzymes serially and maintain continuous ECG monitoring for at least 24-48 hours 7
Healthcare Worker Protection
Given the risk of secondary phosphine gas exposure to medical personnel:
- Use appropriate personal protective equipment including organic vapor filters for air-purifying respirators when managing these patients 5
- Increase ventilation in treatment areas immediately 5
- Avoid direct contact with emesis and gastric contents without proper protection 5
The mortality rate in zinc phosphide poisoning ranges from 25-40% in reported case series, with death resulting from pulmonary edema, cardiovascular collapse, or delayed cardiotoxicity. 3, 4 The absence of specific antidotal therapy and the unpredictable timing of deterioration make aggressive supportive care and continuous monitoring the cornerstones of management.