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Gastrointestinal decontamination

The use of gastric emptying procedures (emesis or lavage) for treatment of the acutely poisoned patient have historically been fundamental principles of toxicology. However, recent literature finds very little convincing evidence that these procedures positively affect patient outcome. It has also become evident that certain subsets of poisoned patients can be treated with activated charcoal alone. In this section we hope to review the indications for and the use of ipecac-induced emesis, orogastric lavage, activated charcoal, and whole bowel irrigation and intestinal evacuants, and help with the decision about whether or not to perform gastric emptying.

Methods of Gastric Emptying
I. Emesis
A. Method:
1. When indicated, emesis is best accomplished with the administration of syrup of ipecac.
(still currently available over the counter but may only be available with a prescription in the future.)
2. This is a plant derivative containing the alkaloids emetine (methylcephaeline) and cephaeline
3. Has both a direct effect on the stomach, as well as a central effect
a. Stimulates the chemotactic trigger zone (cephaeline).
4. When ipecac is not available, 30 mL of a mild dishwashing soap (not electric dishwasher detergent) in water is an acceptable alternative for the induction of emesis, though it is less effective than ipecac.
5. Manual stimulation (placing a finger in the back of the throat), other emetics (saline, hydrogen peroxide, and copper sulfate) are less effective and potentially harmful, and thus should not be used in humans.

B. Efficacy:
1. A single dose of ipecac produces emesis in over 90% of patients; mean time to vomit of ~20 minutes.
2. Although the production of emesis is reliable, the amount of drug recovered ranges anywhere from 6-89% this data comes from studies using swallowed tracers in volunteers and overdose patients, and in one case from direct inspection of the stomach with endoscopy.

C. Indications:
· The 2005 AACT/EAPCCT position paper recommends considering ipecac in an “alert, conscious patient who has ingested a potentially toxic amount of a poison.”
· In 2003, the American Academy of Pediatrics released a policy statement recommending that syrup of ipecac should no longer be used routinely as a home treatment strategy in children following ingestion of a potentially poisonous substance. The first action of a caregiver should be to contact the local poison control center.
· We agree with this recommendation while still appreciating the utility of syrup of ipecac in specific situations. (i.e., a witnessed ingestion of lithium in a healthcare facility; the pre-hospital setting where there will be a long delay in arrival of the patient to a healthcare facility)

1. Acute ingestion of a potentially toxic substance still expected to be in the stomach (generally < 1 hr)
2. Protective airway reflex (gag) intact - mental status expected to remain stable
3. May be effective when pills are too large to pass through the ports in a lavage tube (e.g. some extended release preparations, adult iron supplements, etc.)
4. May be useful with substances that bind poorly to charcoal, such as lithium
5. May be useful when removal of 25-30% of the ingested dose may have a significant influence on patient outcome

D. Contraindications:
1. Non-toxic ingestions - emesis should not be used as a method of punishment.
2. Prior significant vomiting - ipecac induced emesis is no better than “natural” emesis, and would not be expected to recover additional material.
3. Any patient who is comatose, seizing, hypotensive, or has lost his/her protective airway reflex.
4. The patient who is presently awake, but may be expected to rapidly deteriorate before emesis has been completed. Examples of this type of ingestion include TCA, beta-blockers, camphor, and many others.
5. Caustic agents may cause additional injury during emesis.
6. Aspiration risk: ingestions of poorly absorbed hydrocarbons.
7. Sharp objects and other foreign body ingestions.
8. Need for rapid administration of oral antidotes, such as NAC, especially approaching 6-8 hours after APAP ingestion.
9. Late in pregnancy
10. Hypertensive crisis or intracranial hypertension.

E. Dosage:
1. Children under 6 months of age: Contraindicated
2. Children 6 - 12 months: 5-10 mL of ipecac with 15 mL of water/kg body weight
3. Children 1 - 12 years: 15 mL of ipecac with 240 mL of water
4. Adults: 30 mL ipecac with 240-480 mL of water
5. This dose may be repeated in 30 minutes if emesis has not occurred.

F. Complications:
1. Intractable vomiting (rare)
2. Diarrhea
3. Aspiration
4. Myocardial toxicity - associated with extract of ipecac (has 14 times the alkaloidal content of the syrup – production ceased in 1970) or with repeated dosing of syrup as in patients with bulimia.
5. Neuromuscular weakness (seen with chronic abuse in bulimics or with Munchausen’s by Proxy))
6. Mallory-Weiss tear of the esophagus
7. Pneumomediastinum
8. Lethargy
9. Threatened abortion possibly induced by ipecac

II. Gastric Lavage
A. Method:
1. The term “gastric lavage” is used to mean orogastric lavage with a large-bore tube; this is to distinguish this technique from attempts at gastric emptying with a small-bore nasogastric tube.
2. To properly perform orogastric lavage the following steps must be taken:
a. Protect the airway if the gag reflex is absent.
b. Place the patient in the left lateral decubitus position with the head down.
c. Have suction available to clear secretions.
d. Measure the length of tube to be inserted (tragus to nose to xyphoid)
e. Place the tube, and confirm its position.
f. Lavage with adequate volumes of fluid until clear.

B. Orogastric tube size:
Adults: 36-40 French (the larger is preferred)
Children: No smaller than 22-24 French

C. Efficacy:
Variability in studies evaluating the efficacy of this intervention has failed to give a clear answer.
1. Drug recovery varies with choice of experimental models:
a. In one study, 200 mg of barbiturates were recovered from 24 of 65 cases lavaged within 4 hours of ingestion. This fell to 1 out of 65 if lavage was done greater than 4 hours after ingestion.
b. 20 gm of salicylate has been recovered as late as 9 hours after ingestion.
c. Only 32% of drug was recovered by lavage performed in one study under ideal conditions.
2. Comstock demonstrated that lavage of sedative-hypnotic ingestions recovered ³ 2 therapeutic doses in 15.8 percent of cases, and ³10 therapeutic doses in only 6.6 percent of cases.
3. Tracer studies demonstrate recovery of stomach contents between 35 and 56 percent.
4. An endoscopic evaluation of the gastric mucosa post-lavage in overdose patients revealed retention of tablets in some cases.
5. A review of studies addressing the concern of whether gastric lavage causes propulsion of poisons beyond the pylorus and into the small bowel found that this hypothesis is neither supported nor refuted by the literature. (Eddleston)

D. Indications:
1. Any acute poisoning where gastric emptying is indicated and emesis with ipecac is contraindicated. It is preferred when the ingestion occurs within one hour, and a rapid deterioration in mental status or vital signs is expected (i.e. tricyclic antidepressants), or for which even a small decrease in toxic exposure may be critical. (i.e. calcium channel blockers, colchicine, lithium) (Kulig 1985)
2. Lavage is preferred in patients who have lost their gag reflexes, who are intubated for airway protection, and in patients intubated for other reasons.
3. If the ingestion occurs more than one hour prior to presentation, the above indications must be weighed against the contraindications. A time of greater than one hour is not a contraindication.

E. Contraindications:
1. Caustic ingestions
2. Large foreign bodies or sharp objects
3. Inability to protect the airway (or no endotracheal tube)
4. When drug is no longer considered to be accessible in the stomach

F. Complications:
1. Aspiration pneumonia
2. Esophageal or gastric perforation
3. Tension pneumothorax and empyema
4. Decreased oxygenation during the procedure

Comparison of emesis and lavage
A. The studies comparing the use of ipecac-induced emesis to gastric lavage produce a variety of results that seem dependent on the experimental model - use of drug, size of lavage tube, timing of procedures, and host (animal or human).
B. All of these studies look at drug recovery alone and not clinical outcome.
C. Under most circumstances ipecac and lavage produced similar recoveries.

Other Gastrointestinal Decontamination Methods
III. Activated charcoal
A. Method:
1. Activated charcoal is a fine black powder prepared by pyrolysis (burning) of carbonaceous products. “Activation” increases the surface area of the particles.
2. Toxins adsorb (stick) to activated charcoal, and thus the total surface area of the charcoal preparation is related to the amount of drug able to be adsorbed. Typical preparations have surface areas of 950 square meters/gram (USP).
3. Some toxins are not well adsorbed to activated charcoal. They include most small molecules (iron, the alcohols, lithium, strong acids and alkalis, sodium, chloride etc.)

B. Dose:
The optimal dose of charcoal for most well adsorbed toxins seems to be a 10:1 charcoal to drug ratio. For unknown ingestions dosing is based on ability to tolerate the agent:

Adults: 60 to 90 grams Children: 1 gram/kg body weight

How is a digoxin overdose different from a theophylline overdose? A lethal digoxin overdose may be 20 or 25 mg. It would be easy to give charcoal in a 10:1 or even 1000:1 ratio. A theophylline overdose of equal implications might involve an ingestion of 30 grams. Here it would be difficult to achieve a 10:1 charcoal to drug ratio. This underscores the need for gastric emptying or prevention of systemic absorption by other means.

C. When do we use multiple-dose activated charcoal?
1. Multiple doses of activated charcoal have proven effective patients with ingestions of phenobarbital, dapsone, theophylline, digitoxin, phenytoin, carbamazepine, and several other drugs. Most toxins have not been investigated.
2. Although multiple-dose activated charcoal has never before been shown to positively affect patient outcome, a study done in Sri Lanka did find effectiveness in reducing deaths and life-threatening cardiac arrhythmias after yellow oleander poisoning.
3. In general, multiple doses of charcoal should be given to decrease ongoing absorption of drug ingested (sustained release products, drugs that form concretions in the GI tract, etc).
4. Also, they should be used to enhance elimination of drugs in patients who are clinically ill and have ingested drugs whose pharmacokinetics (low Vd, low PB, long t1/2, enterohepatic or enteroenteric circulation) makes them accessible to adsorb to charcoal.

D. Contraindications:
1. Absent gut motility or perforation. When GI motility is decreased, residual charcoal can be removed from the stomach with a nasogastric tube to avoid aspiration.
2. When endoscopic visualization will be required - as in caustic ingestions.
3. Loss of protective airway reflexes.

E. Cautions:
Always advise health care professionals to check if their charcoal preparation contains a cathartic. Repeat dosing of activated charcoal that contains a cathartic should never be administered, as significant fluid and electrolyte abnormalities can result.

F. Complications:
In 2003, a review of 878 patients who received multiple dose activated charcoal found that clinically significant complications occur infrequently. Although complications are rare, they may include:
1. Fatal aspiration (Menzies 1988)
a. Aspiration can have devastating pulmonary consequences such as empyema or ARDS, often leading to death.
2. Small bowel obstruction

Comparison of ipecac and activated charcoal
In most studies, activated charcoal is superior to ipecac-induced emesis for removal of common drugs that are adsorbed to activated charcoal.

Clinical implications: to empty or not to empty?
A. It remains unclear whether ipecac is superior to gastric lavage for drug removal. However, other important considerations must be taken into account.
1. Ipecac induced emesis delays the administration of activated charcoal or oral antidotes.
2. Ipecac is not appropriate for use in patients with altered mental status, or the potential for rapid deterioration in vital signs.
3. Large-bore lavage is not feasible in small children.
4. Some pills that do not readily disintegrate may not fit through the ports of a lavage tube.

Overview Of The Literature
A. Kulig (1985) looked at the efficacy of ipecac, gastric lavage, and activated charcoal in 592 acute overdoses.
1. Gastric lavage was only shown to improve clinical outcome if performed on obtunded patients within 1 hour of ingestion.
2. Ipecac induced emesis at any time, or lavage after one hour post-ingestion showed no significant difference in outcome when compared to activated charcoal alone.
3. However, many of the sickest patients were removed from the study, because of concern about randomizing them to a non-gastric emptying arm.
B. Pond (1995) repeated this study and found no difference in outcome even in the sickest patients.
1. Among several problems with this study: 124 patients were excluded and 82 did not receive the assigned treatment; there were a small number of severely intoxicated patients; there was a delay in the treatment of the gastric emptying group vs. the not emptied group.
2. In retrospective power analyses, the study had sufficient power to detect a twofold benefit in the gastric emptying, and the results suggested benefits to the sickest patients with gastric emptying.
C. A similar study by Merigian (1990) also failed to demonstrate any advantage for aggressive gastric decontamination.
D. The studies by Kulig and Pond failed to show any benefit for gastric emptying over activated charcoal alone one-hour post ingestion. This does not mean that a benefit does not exist, it means that the study failed to show a benefit .
E. All of these studies are flawed in that all patients where gastric emptying was likely to have the greatest benefit over activated charcoal alone (where the toxins ingested are not adsorbed by activated charcoal) were excluded from the study. These studies do, however, demonstrate that many patients can be managed with activated charcoal alone. There is no solid evidence presented to completely abandon lavage or ipecac.
F. Gastric lavage should be considered for all critically ill patients who have required intubation as a result of their poisoning.

IV. Whole Bowel Irrigation
Whole bowel irrigation refers to the mechanical cleansing of the entire gastrointestinal tract by the instillation of large volumes of fluid. Early attempts with Ringer's lactate or normal saline produced significant edema, as well as electrolyte abnormalities.

With the advent of polyethylene glycol solutions, this problem seems to have been overcome. Commercially available as Nulytely (approved in children and adults, contains 52% less salt than Golytely or Colyte), Colyte or Golytely, these solutions contain a 3500 molecular weight polyethylene glycol molecule, in a balanced salt solution. Thus they are isotonic (don't cause large electrolyte shifts).

Whole bowel irrigation produces a rapid catharsis, clearing most matter from the GI tract in hours. It has been used safely in small children, and appears to be effective both in experimental overdose models, and in actual toxic ingestions. While it is not a substitute for activated charcoal, it seems to have its greatest utility in ingestions of agents not well adsorbed to charcoal (iron, lead, lithium, zinc) and in sustained release products.

Other advantages of whole bowel irrigation have been demonstrated in gastrointestinal drug concealment. Both “body-packers” and certain “body-stuffers” (i.e. those who swallow crack vials) have been successfully managed with whole bowel irrigation.

A. Indications:
1. The potentially toxic ingestion of a substance not well adsorbed to activated charcoal.
2. Substances with a prolonged absorption phase – like sustained release preparations.
3. Rising drug levels despite gastric emptying and the use of activated charcoal (SR products)
4. Gastrointestinal drug smuggling

B. Contraindications:
1. Absent bowel sounds
2. Bowel obstruction or perforation
3. Unprotected compromised airway
4. Haemodynamic instability

C. Dose:
1. Adults – 1.5-2 liters per hour (minimally)
2. Children 500 mL per hour or 25 mL/kg/h.
3. This is given orally or via a nasogastric tube (preferred.)
4. Administration is continued until rectal effluent is clear .
5. Administer activated charcoal before and after WBI for drugs adsorbed to activated charcoal

D. Complications
1. Vomiting or bloating frequently occurs.
2. Rectal irritation has also been noted.

E. Adjuncts
1. Antiemetics (preferably metoclopramide) are often required
2. Consider promotility agents (erythromycin, metoclopramide) in addition to WBI for patients with well constructed drug packets

F. Why not whole bowel irrigate everybody?
In a number of studies WBI solution has been shown to occupy activated charcoal's binding sites; this means that the addition of WBI solution can liberate toxin from charcoal, potentially increasing toxicity and it may interfere with charcoal's overall efficacy. It is also labor intensive and messy.

V. Cathartics
The utility of cathartic administration in the management of acute overdose has not been well established. Some authors argue that charcoal preparations are constipating and that cathartics relieve this. Decreased transit time may prevent continued absorption of toxins in the GI tract; however, many experimental models have not been able to demonstrate this.

Demonstration of a desorption phenomenon in salicylate overdose (salicylate levels can increase late in the course of overdose presumably from the release of salicylate from charcoal) has strengthened arguments for a routine use of ONLY a single dose of cathartic.

Only a single study was able to demonstrate a potential benefit for cathartic administration.
1. A tracer study in volunteers using theophylline and radio-opaque tablets found that sorbitol increased recovery of the radio-opaque tablets, but did not alter absorption of theophylline.
2. No studies to date have demonstrated an improvement in clinical outcome with cathartics alone .

A. Indications
1. Acute overdose requiring multiple doses of activated charcoal. Should only be given with the first dose of charcoal; subsequent doses should be without cathartic.
2. Not recommended in pediatric patients, or in a patient with a low risk, or trivial ingestion.

B. Contraindications
1. Children less than 1 year of age
2. Presence of diarrhea, or following exposure to a toxin expected to produce significant diarrhea
3. Absent bowel sounds

C. Dosing
1. Magnesium sulfate (powder)
Adults: 20-30 grams Children: 250 mg/kg up to a max of 30 gm
2. Magnesium sulfate (10% solution)
Adults: 150 - 250 mL Children: 2.5 mL/kg up to a max of 150 mL
3. Magnesium citrate (10% solution)
Adults: 250 mL Children: 4 mL/kg up to a max of 250 mL
4. Sorbitol (usually available as a 70% w/v solution)
Adults: 0.5-1 gram/kg Children 0.5 gram/kg with max of 50 g of a 35% solution if > 5 years

D. Which cathartic should be used?
For any given cathartic there is significant variation in the effect on gastrointestinal transit times.

1. A pediatric study found that gastrointestinal transit times averaged 8.48 hours for sorbitol, 12.8 hours for magnesium citrate, and 22.6 hours for magnesium sulfate.
2. Catharsis from sorbitol is generally quicker than that obtained from either magnesium sulfate or magnesium citrate. (Krenzelok 1985)
a. Sorbitol (>100 gm) - 1.3 hours
b. Magnesium citrate - 4.1 hours
c. Magnesium sulfate - 16.7 hours
3. Sorbitol is sweet tasting but has the disadvantage of abdominal cramping.

E. Precautions
1. Repetitive dosing of magnesium containing cathartics is associated with significant hypermagnaesemia in pediatric patients, patients with renal failure, and in patients with normal renal function.
2. Repeat dose sorbitol is potentially dangerous as it can cause dramatic fluid shifts. Severe hypernatraemia has been reported.
3. For substances that do not bind well to charcoal and require rapid gastrointestinal elimination, whole bowel irrigation is much safer than repetitive cathartics.

What is the role of endoscopy and/or surgery in GI decontamination?
Aggressive intervention is almost never indicated; exceptions have included the treatment of gastrointestinal drug smuggling, and iron overdose.

Suggested Readings
While some of the conclusions expressed in the following position papers do not necessarily represent the opinions of the staff of the New York City Poison Control Center.

1. Guidelines for the management of poisoning consensus panel. Guidelines on the use of ipecac syrup in the out-of hospital management of ingested poisons. Clin Toxicol 2005; 43(1): 1-10.
2. Policy Statement: Poison Treatment in the Home. American Academy of Pediatrics. Pediatrics. 2003; 112(5): 1182-1185.
3. Position paper: cathartics. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. Clin Toxicol. 2004; 42(3): 243-253.
4. Position paper: gastric lavage. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. J Toxicol Clin Toxicol. 2004; 42(7): 933-943.
5. Position paper: single-dose activated charcoal. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. Clin Toxicol. 2005; 43(2): 61-87.
6. Position paper: whole bowel irrigation. American Academy of Clinical Toxicology; European Association of Poison Centres and Clinical Toxicologists. J Toxicol Clin Toxicol. 2004; 42(6): 843-854.
7. Position statement and practice guidelines on the use of multi-dose activated charcoal in the treatment of acute poisoning. American Academy of Clinical Toxicology; European Association of Poisons Centres and Clinical Toxicologists. J Toxicol Clin Toxicol. 1999; 37(6): 731-751.
8. de Silva HA, Fonseka MM, Pathmeswaran A, et al.: Multiple-dose activated charcoal for treatment of yellow oleander poisoning: a single-blind, randomised, placebo-controlled trial. Lancet. 2003;361:1935-8.
9. Manoguerra AS, Cobaugh DJ: Guidelines for the Management of Poisoning Consensus Panel. Guideline on the use of ipecac syrup in the out-of-hospital management of ingested poisons.Clin Toxicol (Phila). 2005;43(1):1-10.

Selected References
Albertson TE, et al. Superiority of activated charcoal alone compared with ipecac and activated charcoal in the treatment of acute toxic ingestions. Ann Emerg Med 1989; 18:56-59.
Auerbach PS, et al. Efficacy of gastric emptying: gastric lavage versus emesis induced with ipecac. Ann Emerg Med 1986; 15:692-8.
de Silva HA, et al. Multiple-dose activated charcoal for treatment of yellow oleander poisoning: a single-blind, randomised, placebo-controlled trial. Lancet. 2003 Jun 7;361(9373):1935-8
Dorrington CL, et al. The frequency of complications associated with the use of multiple-dose activated charcoal. Ann Emerg Med 2003; 41:370-377.
Eddleston MJ, et al. Does gastric lavage really push poisons beyond the pylorus? A systematic review of the evidence. Ann Emerg Med 2003; 42:359-364.
James LP, et al. A comparison of cathartics in pediatric ingestions. Pediatrics 1995; 96:235-238.
Keller RE. Contribution of sorbitol combined with activated charcoal in prevention of salicylate absorption. Ann Emerg Med 1990; 19:654-656.
Kirschenbaum LA, et al. Interaction between whole-bowel irrigation solution and activated charcoal: implications for the treatment of toxic ingestions. Ann Emerg Med 1990; 19:1129-1132.
Kulig K, et al. Management of acutely poisoned patients without gastric emptying. Ann Emerg Med 1985; 14:562-567.
Merigian KS, et al. Prospective evaluation of gastric emptying in the self-poisoned patient. Am J Emerg Med 1990; 8:479-483.
Manoguerra AS, Cobaugh DJ. Guidelines for the management of poisoning consensus panel. Guidelines on the use of ipecac syrup in the out-of-hospital management of ingested poisons. Clin Toxicol 2005; 43(1): 1-10.
Pond SM, et al. Gastric emptying in acute overdose: a prospective randomised controlled trial. Med J Australia 1995; 163:345-349.
Saetta JP, Quinton D. Residual gastric content after gastric lavage and ipecacuanha-induced emesis in self-poisoned patients: an endoscopic study. J Royal Soc of Med 1991; 84: 35-38.
Saetta JP, et al. Gastric emptying procedures in the self-poisoned patients: are we forcing gastric content beyond the pylorus? J Royal Soc of Med 1991; 84:274-276.
Tennenbein M, Cohen S, Sitar DS. Efficacy of ipecac-induced emesis, orogastric lavage, and activated charcoal for acute drug overdose. Ann Emerg Med 1987; 16:838-841.

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