Toxicologic decontamination (Proceedings)

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Toxicologic decontamination (Proceedings)

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Apr 01, 2008
By dvm360.com staff

General concepts:

The goal of decontamination is to prevent the continued absorption of the toxicant. Owners and staff should be advised to protect themselves from toxic exposure when decontaminating a patient; this principle is particularly true with dermal toxins and toxins that are easily volatilized.

Toxicity

Exposure assessment should always be attempted to estimate the dose compared to the known toxicity of the compound. If the dose approaches the toxic range then vigorous decontamination procedures are justified.

Type of substance

Various chemical of physical properties of individual toxins may indicate or preclude particular decontamination techniques. Examples of such restrictions would be the high risk of aspiration pneumonia following emesis after ingestion of volatile hydrocarbons.

Time since exposure

This is a critical factor. Many studies have exhibited a significant decrease in recovery of toxins with a variety of decontamination techniques as the time from exposure increases.

Species affected

Species differences in both physiology and anatomy often necessitate changes in decontamination techniques used for a similar toxin. Some species for example do not vomit and trying to lavage a rumen is difficult due to the volume involved.

Underlying disease

Some decontamination techniques require stresses both on the animal and various organ systems which would preclude their use in animals with preexisting pathology in those organ systems. An example would be attempting urine alkalization in a patient with underlying renal disease.

Routes of exposure and decontamination methods

Topical:

Ocular

Ocular exposures require copious flushing with water or physiologic saline. Flushing should continue for a minimum of 15 minutes, and sedation maybe necessary in some patients. Multiple flushings are often necessary.

Dermal

Dermal exposures allow for both transdermal absorption and oral exposure as the animal tries to clean itself. Rubber gloves and plastic aprons should be used by all decontaminating personnel. Victims with long hair coats may benefit from having the hair clipped before cleaning the skin. Mild soaps will remove most toxins, but multiple washings maybe necessary. Try to minimize trauma to the skin which could enhance absorption of the toxin. Oily substances can often be removed with commercial mechanics hand degreasing agents such as GOJO and or GOOP. These degreasers then need to be washed off to prevent the subsequent ingestion by the patient. Monitor the patient to prevent hypothermia, aspiration or ingestion of the toxin, soap or combination of both.

Particularly difficult dermal decontaminations involve acid or caustic substances with the resultant dermal burns. These require gentle washing with copious volumes of tepid water and mild soaps, trying to minimize trauma.

Gastrointestinal:

Gastric evacuation
Emesis

The following is the position paper for ipecac syrup in humans but is applicable to apomorphine or other emetics. *"Syrup of ipecac should not be administered routinely in the management of poisoned patients. In experimental studies the amount of marker removed by ipecac was highly variable and diminished with time. There is no evidence from clinical studies that ipecac improves the outcome of poisoned patients and its routine administration in the emergency department should be abandoned. There are insufficient data to support or exclude ipecac administration soon after poison ingestion. Ipecac may delay the administration of reduce the effectiveness of activated charcoal, oral antidotes, and whole bowel irrigation. Ipecac should not be administered to a patient who has a decreased level or impending loss of consciousness or who has ingested a corrosive substance or hydrocarbon with high aspiration potential".

Gastric lavage
*"Gastric lavage should not be employed routinely, if ever, in the management of poisoned patients. In experimental studies, the amount of marker removed by gastric lavage was highly variable and diminished with time. The results of clinical outcome studies in overdose patients are weighed heavily on the side of showing a lack of beneficial effect".