Chapter 61. Whole Bowel Irrigation

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. Most of the literature supporting its use is in the form of case reports or case series.1 While available reports are compelling, the indications for whole bowel irrigation are mostly theoretical and will be refined as more extensive data become available. The role of whole bowel irrigation currently remains limited.

Current methods of gastrointestinal decontamination (i.e., emesis, gastric lavage, and activated charcoal administration) focus primarily on decontaminating the stomach. Absorption of most toxicants occurs principally in the proximal small bowel. Sustained- or delayed-release preparations continue to liberate 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.2 This reduces absorption of the drug or toxin throughout the gastrointestinal tract. The 3500 Da molecular weight polyethylene glycol solution is specifically designed to prevent electrolyte and fluid shifts.

Whole bowel irrigation may be indicated for acute ingestions where severe or potentially fatal toxicity is anticipated (Table 61-1). Other decontamination methods, such as activated charcoal, should be employed if they are known to be effective rather than whole bowel irrigation. Whole bowel irrigation may be indicated in situations where activated charcoal is known to be ineffective. Whole bowel irrigation has been safely utilized to decrease bioavailability of ingested iron, lithium, and heavy metals.3–7 Whole bowel irrigation has been proposed to be effective in flushing the gastrointestinal tract free of toxicant before absorption can be affected by sustained-release preparations.8 Whole bowel irrigation may speed gastrointestinal transit of ingested packets or vials of illicit drugs ingested by a “body packer.”9 Recently, the role of whole bowel irrigation in the “body stuffing syndrome” has recently been questioned.10 While the indications are limited, additional settings may be envisioned where whole bowel irrigation might be useful. Unfortunately, there is not yet data to support broader indications.

There are few contraindications to performing whole bowel irrigation (Table 61-2). It should not be used in the setting of a patient with a potentially compromised or unprotected airway. Whole bowel irrigation could result in pulmonary aspiration.11,12 Significant vomiting will hinder the ability to perform whole bowel irrigation. It should not be performed in the hypotensive or hemodynamically unstable patient.11 Other contraindications include abnormal upper airway or upper gastrointestinal anatomy (e.g., anomalies, strictures, or fresh interposition graft). Ingestion of toxic substances that markedly slow gastrointestinal motility (e.g., anticholinergics or opioids) may cause an ileus, diminishing the ability to perform whole bowel irrigation effectively. The administration of polyethylene glycol in a patient with a bowel obstruction will result in vomiting with the potential for aspiration. This solution should not be used in patients with an actual or suspected perforated bowel. The risk of whole bowel irrigation is quite small but the procedure is not without effort, expense, and risk of complications. In this light, the risk–benefit ratio would be high if whole bowel irrigation were used to treat a nontoxic ingestion.

• Nasogastric or enteral feeding tube, size 10 to 12 French
• Water-soluble lubricant
• Nasal decongestant and anesthetic
• Enteral feeding reservoir and tubing
• Polyethylene glycol electrolyte lavage solution (packets or reconstituted)
• Emesis basin
• Stethoscope
• Toomey syringe
• Intravenous extension tubing

The equipment required for whole bowel irrigation is readily available in most Emergency Departments. A small-bore, 10 to 12 French, nasogastric tube is sufficient for an adult or adolescent. An enteral feeding tube can be substituted if a sufficient flow rate can be ensured. A smaller tube is required in infants or very small children. Infants will tolerate an 8 French tube and a 10 to 12 French tube is adequate beyond the first year.13,14

Standard enteral feeding reservoirs and tubing are typically available as packaged kits. An enteral feeding or an enema bag with enteral feed tubing may be substituted. Enteral feeding pumps, however, are not useful, as the flow rate through the pump is typically inadequate to perform whole bowel irrigation effectively. Alternatively, an empty 1 L intravenous fluid bag with intravenous extension tubing can be used for the procedure.

Explain the procedure, its risks, its benefits, and alternatives to the patient and/or their representative. Informed consent should be obtained. Informed consent can be assumed in the case of suicidal ingestions. Inspect the nasal passages and oropharynx to rule out any anatomic abnormalities or obstruction that would preclude the passage of a nasogastric tube.

Place the patient in the upright or semi-upright position (Figure 61-1).14 The supine and lateral decubitus positions are associated with a higher risk of pulmonary aspiration in comatose and mechanically ventilated patients.15–18 It can be assumed that this positioning risk is similarly increased in patients undergoing whole bowel irrigation.

It is recommended that a cardiac monitor, noninvasive blood pressure cuff, and pulse oximeter be placed on the patient prior to performing gastric lavage. This equipment may also be required based upon the patient's physiologic status, the nature of the ingestant or toxicant, and/or other underlying problems.

Choose the smallest diameter nasogastric or feeding tube that will allow adequate flow of polyethylene glycol electrolyte lavage solution into the stomach. All necessary equipment should be placed at the bedside and assembled prior to beginning the procedure.

A cuffed endotracheal tube should be placed prior to performing whole bowel irrigation in patients who are comatose, drowsy, obtunded, unconscious, or have an absent or impaired gag reflex. Endotracheal intubation should be strongly considered in any patient who has ingested a central nervous system depressant, tricyclic antidepressants, a sympathomimetic or other agent that may result in seizures, or any substances that can cause an altered mental status.

Insert a nasogastric tube. Refer to Chapter 58 for the complete details regarding nasogastric tube placement. Measure the length of the nasogastric tube to be inserted. Place the tip of the nasogastric tube over the xiphoid process. Extend the tube over the anterior chest, lateral neck, behind the angle of the mandible, and to the tip of the nose. Mark this length with a permanent marker or a piece of surgical tape. Liberally lubricate the tip of the nasogastric tube. The application of a nasal anesthetic and decongestant is optional but can facilitate the passage of the nasogastric tube.

Gently insert the nasogastric tube into the naris. Advance it posteriorly along the nasal floor into the nasopharynx and through to the hypopharynx. Flexion of the neck may facilitate passage of the tube into the esophagus and avoid endotracheal insertion. The conscious and cooperative patient may be asked to swallow water through a straw or to swallow their saliva to facilitate passage of the tube. Stridor, cough, or cyanosis may indicate endotracheal passage and should prompt removal of the tube. Gentle pressure and patient swallowing should allow passage through the upper esophageal sphincter if significant resistance is met in the hypopharynx. Do not force the nasogastric tube as misplacement may damage the larynx or perforate the pyriform sinus. Advance the nasogastric tube to the marked level. Confirm proper placement by the aspiration of gastric contents, by auscultation of insufflated air over the epigastrium (from a 50 mL syringe), and/or by radiography. Confirmation of intragastric placement must precede administration of any fluids through the nasogastric tube. A radiograph must be obtained prior to using the nasogastric tube if any question exists regarding its position.

Instill the polyethylene glycol electrolyte lavage solution through a setup such as that shown in Figure 61-1. Flow rates are dependent upon the size of the patient. Begin instillation at an initial rate of 25 to 30 mL of polyethylene glycol electrolyte lavage solution per kilogram per hour. Adults may tolerate more than 3 L of solution per hour. The rate may be adjusted somewhat to accommodate patient tolerance (e.g., vomiting, abdominal distension). Irrigation should be continued until the patient passes the ingestant in the stool or until clear liquid rectal effluent is passed. Liquid stools will continue to be passed after discontinuing whole bowel irrigation. Stop the irrigation if the patient vomits, develops an ileus, or if gastrointestinal perforation is suspected.

Some Emergency Physicians may attempt whole bowel irrigation by offering the patient polyethylene glycol electrolyte lavage solution to drink. This is rarely successful. Experience shows that whole bowel irrigation is ineffectively performed if a nasogastric tube is not placed. Even the most cooperative patient is unlikely to drink the solution at the required administration rate.

Patient assessment must be continuous throughout the process of whole bowel irrigation. Mild abdominal distention, gassiness, and mild abdominal discomfort are common side effects and do not require the discontinuation of the infusion. Providers must be vigilant in monitoring the patient's bowel sounds. If bowel sounds cease or significant abdominal distension is noted, the irrigation should be held for 30 to 90 minutes and the patient reassessed. Resume the irrigation at a reduced rate if bowel sounds return, if the clinical status improves, and if the patient then tolerates the infusion. Significant electrolyte or osmotic shifts do not occur solely from whole bowel irrigation. Electrolytes may be monitored if otherwise indicated for the type of ingestion or for overall patient status. Of greater concern is vomiting with the risk of aspiration. The patient's posture should be maintained in the upright sitting or the semi-upright position to facilitate passage of irrigant solution into the small bowel and to protect against aspiration. Discontinue whole bowel irrigation if the patent develops an altered mental status or hemodynamic instability.

Patients who undergo whole bowel irrigation must all be admitted to the hospital for ongoing assessment of the intervention and the underlying ingestion or overdose. In most cases, intensive care or step-down monitoring will be required to ensure adequacy of the intervention and to monitor for complications of the ingestion or overdose. Delayed complications from whole bowel irrigation are unlikely once the procedure is completed.

Documented complications from whole bowel irrigation include pulmonary aspiration of the irrigant solution and/or ingestant.11,12 This would be especially concerning in the patient with an unprotected and potentially compromised airway. An ileus and intestinal distension has been documented in a hypotensive patient receiving whole bowel irrigation.12

Osmotic and electrolyte abnormalities will not occur with the standard preparations of high molecular weight (c. 3500 Da) polyethylene glycol electrolyte lavage solutions (e.g., Colyte, GoLYTELY, NuLYTELY). Complications of nasogastric tube placement are well described and can occur. Refer to Chapter 58 for the complications associated with nasogastric intubation. These are unlikely if proper technique is employed and can be minimized by use of the smallest effective diameter nasogastric tube.

Whole bowel irrigation is a technique performed to speed gastrointestinal transit and decontaminate the gut after an acute toxic ingestion. Available reports suggest that whole bowel irrigation can decrease bioavailability of toxicants by two-thirds in volunteers.4,14 It may be useful where activated charcoal is not expected to adequately bind ingestants (e.g., iron, lithium). Efficacy is still undefined in the setting of sustained- or delayed-release preparations. Whole bowel irrigation is not the method of choice, however, when more effective methods of gastrointestinal decontamination are possible (e.g., repetitive-dose activated charcoal for sustained-release theophylline). Until further data emerge, whole bowel irrigation's role in managing the toxic ingestion remains limited.