Chapter 78: Whole Bowel Irrigation

INTRODUCTION

Whole bowel irrigation is the infusion of polyethylene glycol electrolyte lavage solution into the stomach at flow rates higher than are otherwise commonly used. This technique can be used to decontaminate the gastrointestinal tract after an acute toxic ingestion or overdose. The goal is to give a large volume of a balanced electrolyte solution rapidly to flush the bowel without creating electrolyte disturbances while removing the ingestant. Most of the literature supporting its use is in the form of case reports or case series, with cohort studies indicating benefit that is of unclear clinical significance and does not support broad use of the therapy.¹ Demonstrated benefits are small.² The indications for whole bowel irrigation are mostly theoretical and will be refined as more extensive data becomes available.³ The role of whole bowel irrigation remains limited.

ANATOMY AND PATHOPHYSIOLOGY

Current methods of gastrointestinal decontamination (i.e., activated charcoal, emesis, and gastric lavage) focus primarily on decontaminating the stomach. Absorption of most toxicants occurs principally in the proximal small bowel. Sustained-release or delayed-release preparations continue to liberate the drug during intestinal transit that is then available for absorption throughout the bowel. Infusion of polyethylene glycol electrolyte lavage solution decreases the enteric transit time, attenuating the contact time of a toxicant with the gastrointestinal mucosa.⁴ This reduces absorption of the drug or toxin throughout the gastrointestinal tract. The high molecular weight PEG 3350 polyethylene glycol electrolyte lavage solution (PEG-ELS) is specifically designed to prevent electrolyte and fluid shifts.

INDICATIONS

Whole bowel irrigation may be indicated for acute ingestions where severe or potentially fatal toxicity is anticipated (Table 78-1). Use other decontamination methods (e.g., activated charcoal) if they are known to be effective rather than whole bowel irrigation. PEG-ELS has been shown to decrease the effectiveness of activated charcoal in some poisonings. An initial dose of activated charcoal may increase the effectiveness of whole bowel irrigation.^5,6 Whole bowel irrigation may be indicated in situations where activated charcoal is known to be ineffective. Whole bowel irrigation has been safely used to decrease bioavailability of ingested iron, lithium, and heavy metals, and it may decrease the poisoning severity associated with lithium overdose.^7-12 Whole bowel irrigation has been proposed to be effective in flushing the gastrointestinal tract free of toxicant before absorption of sustained-release preparations.¹³ Whole bowel irrigation may speed gastrointestinal transit of ingested packets or vials of illicit drugs ingested by “body packers” who purposely ingest carefully prepared drugs as a means of internal concealment for transportation.¹⁴ The role of whole bowel irrigation in “body stuffers” who hastily ingest drugs to avoid legal prosecution has been questioned.¹⁵ Additional settings may be envisioned where whole bowel irrigation might be useful. There are no data to support broader indications.