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Link to: Decontamination: Problems for Discussion


Decontamination


Overview

Decontamination refers to the techniques that reduce the exposure to a drug or toxin by reducing absorption. As will all actions in clinical toxicology decision to proceed with decontamination should be based on a risk/benefit analysis.

Decontamination should always be a lower priority than patient resusciation.

Induced emesis and gastric lavage are techniques that were previously used but are now no longer recommended due to evidence of lower efficacy and higher risk than the other decontamination techniques available.


Activated Charcoal

Porous charcoal has a large surface area that adsorbs most toxins. Most drugs are carbon based and have side chains that may adhere to carbon compounds by either chemical or wek electrostatic forces. It is the preferred method for gastrointestinal decontamination.

Its effectiveness decreases with time. If given within 30 minutes of ingestion, charcoal may decrease the absorption of the ingested compound by up to 70%, this drops to 35% after 1 hour.

The window of effectiveness is generally considered to be within 2 hours for an immediate release preparation and 4 hours for a modified or slow-release preparation. This window may be extended for agents which result in life-threatening toxicity or following massive ingestions where absorption is expected to be delayed.

Drugs not well bound by charcoal include:

  • Hydrocarbons
  • Alcohols
  • Metals, including Li+ and K+
  • Corrosives

The treatment dose of activated charcoal is 50g or 1g/kg activated charcoal PO or via NGT.

In children charcoal may be added to ice cream to make it more palatable.

Complications following activated charcoal include:

  • Vomiting
  • Aspiration
  • Bowel obstruction

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Whole Bowel Irrigation

NSW PIC Procure Document for WBI

WBI physically flushes substances from the gastrointestinal tract using large volumes of polyethylene glycol (PEG) solution until the effluent runs clear.

While WBI is very effective, the practicalities of its implementation have meant that its use is largely limited to specific poisonings where activated charcoal alone is not satisfactory.

It is recommended early following poisoning and should not be used once a patient is unwell with established haemodynamic instability as complications of WBI are more likely in this group.

Drugs amenable to WBI:

  • Sustained release preparations (eg mainly calcium channel blockers)
  • Medications not absorbed by charcoal (eg iron, lithium, potassium)
  • Toxins that can form pharmacobezoars (eg salicylates)
  • Body packers

The treatment dose is 1L/h of PEG solution PO or via NGT or (25mL/kg/h if paediatric patient). It should be continued until the effluent runs clear – which usually occurs following approximately 5L of fluid. Often an antiemetic such as ondansetron or metoclopramide will need to be charted.

Complications of WBI:

  • Normal anion gap metabolic acidosis
  • Aspiration
  • Distraction from resuscitative priorities

Further Reading

  1. Isbister, G. K., and V. V. Kumar. “Indications for Single-Dose Activated Charcoal Administration in Acute Overdose.” Curr Opin Crit Care 17, no. 4 (2011): 351-7. PDF
  2. Juurlink DN. Activated charcoal for acute overdose: a reappraisal. Br J Clin Pharmacol. 2016 Mar;81(3):482-7. doi: 10.1111/bcp.12793. Epub 2015 Nov 9. PMID: 26409027; PMCID: PMC4767212. PDF
  3. Ruben Thanacoody, et al. Position paper update: Whole bowel irrigation for gastrointestinal decontamination of overdose patient. Clinical Toxicology, 2015; 53:1, 5-12, DOI: 10.3109/15563650.2014.989326. PDF
wikitox/decontamination.txt · Last modified: 2024/04/28 23:58 by kharris

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