Whole bowel irrigation

Whole bowel irrigation (WBI) is a medical process involving the rapid administration of large volumes of an osmotically balanced polyethylene glycol solution (GoLYTELY&reg;, CoLyte&reg;), either orally or via a nasogastric tube, to flush out the entire gastrointestinal tract.

History
Whole bowel irrigation was originally developed to cleanse the large bowel before surgery or colonoscopy. Initially a solution of sodium chloride, potassium chloride, and sodium bicarbonate was used but this electrolyte solution was shown to be absorbed by the body, sometimes leading to complications. To solve this problem a specialized irrigation fluid was developed consisting mainly of an iso-osmolar solution of polyethylene glycol. With the polyethylene glycol solution there is negligible fluid or electrolyte absorption and several studies have shown the overall safety of the procedure. Whole bowel irrigation was also suggested as a possible treatment for toxic ingestions. WBI has the effect of mechanically flushing the ingested poison out of the gastrointestinal tract before it can be absorbed into the body. A study provided evidence that whole bowel irrigation is an effective and safe gastrointestinal decontamination procedure for acute poisoning.

Technique
Whole bowel irrigation is undertaken either by having the patient drink the solution or a nasogastric tube is inserted and the solution is delivered down the tube into the stomach. The solution is administered at a rate of 500 mL/h in children 9 months to 6 years, 1000 mL/h in children 6 to 12 years, and 1500 to 2000 mL/h in adolescents and adults. The patient is usually seated on a toilet and the procedure continues until the rectal effluent is clear. The entire procedure usually takes 4 to 6 hours. Often patients vomit (especially if ipecac was given prior to the procedure or following ingestion of a drug that produces vomiting such as aspirin or theophylline), indicating that the rate of infusion may need to be slowed or an antiemetic such as metoclopramide given.

Indications
Whole bowel irrigation is indicated prior to surgery, colonoscopy, or a barium enema to cleanse the bowel. Whole bowel irrigation is not used routinely in poisoning situations. It is usually reserved for patients who have ingested toxic doses of medications not absorbed by activated charcoal (such as iron and lithium), potentially toxic ingestions of sustained-release or enteric-coated drugs, or in the situation of packaged drug ingestion (body packing/stuffing).

Contraindications
Major gastrointestinal dysfunction precludes the use of whole bowel irrigation. WBI is specifically contraindicated in the presence of ileus, significant gastrointestinal hemorrhage, hemodynamic instability, uncontrollable intractable vomiting, bowel obstruction, bowel perforation, and in patients with a decreased level of consciousness with a compromised unprotected airway.

Complications
Minor complications include nausea, vomiting, abdominal cramps, and bloating. Patients with altered mental status or a compromised and unprotected airway are at risk for pulmonary aspiration.