What is the proper procedure for administering a gastric wash with activated charcoal to a patient who has ingested a toxic substance?

Administering Gastric Wash with Activated Charcoal

Activated charcoal should only be administered for known or suspected poisoning within 1 hour of ingestion, and should not be given routinely without direction from a poison control center or emergency medical personnel. 1

Indications for Activated Charcoal

• Indicated for known or suspected acetaminophen overdose within 4 hours of presentation 1
• May be considered if a patient has ingested a potentially toxic substance known to be adsorbed by charcoal up to 1 hour previously 2
• Not effective for binding iron, lithium, alcohols, ethylene glycol, alkalis, fluoride, mineral acids, potassium, acids or bases, organic solvents, inorganic salts, and metals 3

Contraindications

• Do not administer to patients with impaired consciousness without a secured airway due to aspiration risk 4
• Do not use for ingestion of corrosives such as lye, strong acids, petroleum distillates, gasoline, kerosene, paint thinner, cleaning fluid, or furniture polish 5
• Do not administer until after the patient has vomited unless directed by a health professional 5

Proper Administration Procedure

1. Confirm appropriateness: Contact poison control center (800-222-1222 in US) before administration 1

2. Prepare the patient:

   • Ensure patient is fully conscious with intact gag reflex or has a secured airway 4
   • Position patient upright if possible to minimize aspiration risk

3. Prepare the charcoal mixture:

   • Adult dosage: 25-100g (3-12 heaping tablespoons) mixed with a minimum of 8 ounces of water 5
   • Children 10-12 years: 25-50g (3-6 tablespoons) mixed with a minimum of 8 ounces of water 5
   • Children <10 years: 10-25g (1-3 tablespoons) mixed with a minimum of 8 ounces of water 5
   • Mix thoroughly to create a slurry

4. Administration:

   • For conscious patients: Have the patient drink the entire mixture
   • For patients requiring nasogastric tube:
     • Insert orogastric tube (which would also allow lavage if needed) 6
     • Verify proper tube placement
     • Administer charcoal slowly through the tube
     • Flush tube with water after administration

5. Timing considerations:

   • Most effective when given within 1 hour of ingestion 2
   • Effectiveness decreases significantly after 1 hour (47.3% reduction at 30 minutes vs. 21.13% at 180 minutes) 2
   • May still be considered up to 4 hours after acetaminophen ingestion 1

Important Cautions

• Activated charcoal may cause black stools, constipation, and potential intestinal obstruction 3
• It can interfere with medication efficacy by non-specifically binding to medications 3
• Patients with renal impairment may be at higher risk for complications 3
• There is no evidence that administration of activated charcoal improves clinical outcome in all cases 2
• Combination therapy with gastric lavage followed by activated charcoal has not shown additional efficacy compared to activated charcoal alone 7

Follow-up Care

• Monitor for signs of aspiration
• Observe for adequate hydration
• Consider repeat doses only if advised by poison control or for specific scenarios (e.g., sustained-release medications)
• Save the container of the poison if possible for identification 5

Remember that activated charcoal is not a routine treatment for all poisonings and should be used selectively based on the specific toxin, timing, and patient condition under medical guidance.