EP's sometimes have difficulty deciding when to administer whole bowel irrigation and how to implement it. With what common toxins/overdoses would you recommend whole bowel irrigation? How should it be performed?

by
Anne-Michelle Ruha, M.D.
Associate Fellowship Director
Department of Medical Toxicology
Good Samaritan Regional Medical Center
Phoenix, Arizona

The purpose of whole bowel irrigation is to decontaminate the gastrointestinal tract by physically expelling the ingested toxin using large volumes of an osmotically neutral polyethylene glycol electrolyte solution (PEG-ES). There are no established indications for the use of WBI following drug ingestion, which makes it difficult for toxicologists and EPs alike to determine when, if ever, this method of decontamination should be utilized.

While there are no controlled clinical studies showing improved outcome following use of WBI, several volunteer studies have demonstrated a decrease in bioavailability of some drugs with this method.1-3 There are clearly situations in which it is of theoretical benefit. Examples include ingestion of cocaine packages that could produce fatal toxicity if the packages leaked or ruptured, and large ingestions of potentially lethal agents for which there is no adequate alternative method of decontamination (such as iron).

Recommended doses of PEG for WBI are 500 ml per hour in children 9 months to 6 years of age, one liter per hour in children 6-12 years, and 1.5 to 2 liters per hour in adolescents and adults.4 Since patients may not be able to drink at this rate, a nasogastric tube should be placed. The patient should be either in a seated position or the head of the bed elevated at least 45 degrees while the fluid is infusing. This will decrease the likelihood of vomiting.

The endpoint for administration of WBI varies. Irrigation should continue at least until the rectal effluent is clear, which may take many hours. If the goal is to remove packages of cocaine or heroin, WBI should continue until all packets are accounted for. If the goal is to remove pills that are visible on KUB, WBI should continue until a repeat film is negative.

Scientific evidence to support standard use of WBI is lacking and this procedure is not without risks (vomiting, pulmonary aspiration). Situations in which I would use WBI are limited to ingestion of packages of illicit drugs intended for transport and large ingestions of life threatening agents for which there is little therapy to offer. Each situation should be considered individually and the local poison control center can be a valuable resource in aiding in these management dilemmas.

References:
1. Tenenbein M, Cohen S, Sitar DS: Whole bowel irrigation as a decontamination procedure after acute drug overdose. Arch Int Med 1987;147:905-907.

2. Kirshenbaum LA, Mathews SC, Sitar DS, Tenenbein M: Whole-bowel irrigation versus activated charcoal in sorbitol for the ingestion of modified-release pharmaceuticals. Clin Pharmacol Ther 1989;46:264-271.

3. Smith SW, Ling LJ, Halstenson C: Whole-bowel irrigation as a treatment for acute lithium overdose. Ann Emerg Med 1991;20:536-539.

4. Tenenbein M: Position statement: whole bowel irrigation; AACT, EAPCCT. J Toxicol Clin Toxicol. 1997;35(7):753-762.

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