Research Applied to Clinical Practice
by Robert C. Knies, RN MSN CEN
Section Editor


Gastric Decontamination in Toxicologic Emergencies:
Are We Hurting or Helping?

        How many times have you treated an overdose patient by shoving that long, hard, wide, tube down his/her throat and asked, "Is this really doing any good?" Or you pushed and pulled with that 60 cc syringe flushing in over 3000 ml of water and got no pills back? I’ve asked myself these, and other, questions many times, and decided to do a literature search to review the current data and compare it to what is occurring in the "real world".

        The gravity of understanding the significance of toxicological emergencies cannot be taken lightly. In 1990 the American Association of Poison Control Centers documented 1,713,465 cases of people exposed to toxins (1). These numbers do not include the large number of cases that show up in your emergency department with no call to their local poison control center, estimates of these cases are up to 70 percent (2) more than the aforementioned documented cases.

        Whenever review of the treatment of toxicology emergencies or any other life threatening situation is done, primary assessment and intervention are the keys (ABC’s). Airway patency must be ensured, breathing must be assessed and assisted prn (Table 1) and circulation must be assessed and aided as needed. Intravenous access with at least one large bore cannula should be performed. The standard protocols of Naloxone, blood glucose assessment and supplemental 50% dextrose should be administered according to your facility’s protocols (Table 2)

        After stabilization, the next goal is to limit the progression of the toxin though the patient’s metabolism. Since this discussion is about gastric decontamination, respiratory tract or dermatologic toxicological emergencies will not be addressed here. However, special care of the emergency staff should be instituted when treating patients potentially exposed to, or who have ingested; organophosphates, cyanide, or carbamate insecticides. Exposure to the skin, vomitus, or even expired air of these patients can incapacitate the emergency staff treating these patients (3).

        The discussion of gastric decontamination has been reviewed and debated since the early 1800’s (4,5). To put it into perspective, the practitioners must ask themselves before subjecting the patient to any of the following modalities; "Are there reasonable indications that a significant amount of the toxin has not yet been absorbed and that removal of this toxin will impact the outcome of this patient?"

        There have been multiple studies performed and evaluated (6,7,8) to attempt to determine if the patient’s outcome changes based on the gastric emptying method chosen (ipecac induced emesis vs. orogastric lavage), the results are inconclusive. In determining which mode to use, several points need to be considered (see table 3). After these considerations, the last major decision point is "Can the ingested agent be absorbed by activated charcoal?"

        The use of any modality is generally dependent on the time from ingestion of the toxin to presentation in the emergency department. Research has shown that, on average, only 30% of total gastric contents are returned even if treatment is performed within one hour post ingestion (9,10,11). Although this percentage of emptying may be significantly effective and even therapeutic for several hours, either modality (emesis/lavage) is non-beneficial at four hours or greater post ingestion. Also, as is generally common, in emergency departments, most overdose patients do not arrive in the emergency department within that "golden hour". Because of the need for treatment within this one to four hour time period, the risks and benefits of the two modalities requires further review. There are also patient and staff considerations that can impact on the decision of which modality to employ, such as: number of staff available to assist with procedure, the compliance of the patient, the mental state of the patient, etc.

        Ipecac has proven useful, if administered within the golden hour, but the percentages of gastric emptying varies from 2% to 75% (10,12,13). Contained in this treatment modality is the inherent risk of gastric content aspiration; therefore, it should not be used for patients with any risk of airway compromise. It is ideal for home treatment of children when the identity of the agent is known and treatment can begin within the first 60 minutes (table 4). The ever present need for community education concerning accidental poisoning and its effective home-based treatment is another topic which will not be addressed here.

        Complications of the ipecac modality can be very severe including, aspiration pneumonia, diaphragmatic rupture, Mallory-Weiss tear (of which I have seen two) even intra-cerebral hemorrhage (5). Also, these patients cannot be given other oral antidote agents for up to six hours post ipecac, this time lag will impact the effectiveness of charcoal or other antidotes such as N-acetylcystine [NAC] (8). Lastly, there is controversy over the practice of giving patients water after administering ipecac. Proponents of this practice, including this author, argue that encouraging fluids helps activate the ipecac and stimulates a better return of gastric contents, compared to leaving the ipecac to work alone. Another supporting point is that the added water helps dilute the toxin, and decreases the normal "acid burn" associated with the vomiting process.

        Gastric Lavage has also been studied, analyzed and reviewed, and these studies have resulted in varying and controversial opinions. Again, the limiting factors are time of presentation post ingestion and the pharmacodynamics of the agent ingested. For implementation of this modality, recommendations include: The size of the tube (hose) should be 36 - 40 gauge French, with multiple large holes at varying distances from distal end and an open distal end. A naso-gastric tube is not recommended because of its inability to remove pills and pill fragments (8,5). Endotracheal intubation is also highly recommended, for securing of the airway and to prevent aspiration. Even with intubation, there have been documented cases of patients aspirating gastric contents post extubation (14). Torres, et al., (1992) [15] have demonstrated that gastric contents can be identified in virtually all lavaged patient’s lungs despite intubation. Also, the act of intubation itself may cause gagging leading to aspiration. Another common recommendation is to have the patient in the left lateral decubitus position for the lavage process. Realistically, however, if a patient is at any level of consciousness he/she will resist the "hose", and not remain in this position. Currently, the most common clinical practice is to have the patient sitting in an upright position when performing lavage.

In addition to aspiration, other potential complications include:

• Incomplete emptying of the gastric contents, especially pills, due to the inadequate size of the holes in the hose.
• Ineffective lavaging technique: overflowing the stomach by instilling too much water, which leads to the patient vomiting around the tube, significantly increasing the risk of aspiration.
• Forceful manual or mechanical aspiration (suctioning) in an attempt to clear hose of stomach contents, can result in damage of gastric mucosa and subsequent bleeding.
• Esophageal rupture caused by forceful passing of the tube, or attempting this procedure with an uncooperative patient.
• Lastly, studies have indicated that the lavage process "pushes" the agent in to the small bowel, accelerating their absorption (3).

        Considering all the risks and complications already discussed the question becomes "Is gastric emptying required at all?" The key to answering this question is determining the ability of activated charcoal to absorb the agent. Charcoal has gained popularity over the past 20 years, because of its great absorption effects, 500mg to 1000mg of agent per 1 gram of charcoal (5). Many studies, presented in the reviewed articles, tout the use of charcoal alone without gastric emptying, but none came to a definitive conclusion . See Table 5 for dosing information.

        There are, however, several controversies surrounding the use of charcoal. First, it is not effective with the following; metals, lithium, iron, and ethanol. Second, it may stimulate vomiting (risking aspiration) which can cause damage to other tissues if used with caustics, petroleum distillates, etc. Third, it impedes the action of other oral antidotes, such as NAC. Lastly, to be effective it should be given in repeated doses. This can be accomplished by inserting a naso-gastric tube, and setting up a continuous drip system. This format helps decrease the risk for aspiration and avoids the need of the patient to swallow the charcoal slurry (5).

        Finally, some discussion on use of cathartics is indicated. Most manufactures are producing activated charcoal in two forms, either mixed with saline or with saccharides acting as the slurry base. There are three types of saccharides, sorbitol, mannitol and lactulose; the most common is sorbitol. The purpose of using this mode of therapy is it’s osmotic effect in the bowel, which stimulates propulsion and peristalsis leading to increased purgation, and in theory, moving the toxic agent (bound with charcoal) through the bowel faster, thereby decreasing absorption. Sorbitol has been found to work the fastest with the fewest complications (8).

        Complications of this modality can include, constipation, fluid and electrolyte imbalance, excessive gas production, and potential ileus. If repeated doses of charcoal are planned, the patient should receive only one dose of the cathartic added form, as subsequent doses may contribute to the aforementioned complications.

        Many of the articles reviewed, discuss whole bowel irrigation, because this modality is not commonly employed in emergency departments, I will defer this issue to another venue.

        In conclusion, as with any other treatment or intervention, the benefits of gastric decontamination in relation to it’s risks and expected outcomes must be evaluated. No specific modality can be totally ruled out. The choice of modality is made more complex when patients use multiple agents in an overdose. We can never eliminate the option of gastric lavage from the treatment regime, but given its inherent risks and documented poor results, the use of gastric lavage requires evaluation with each individual case.

 Table 1

Indications for Intubation of Patients in Overdose Situations

Poor respiratory effort

	less than 12 breaths per minute
	SAO2 less than 90%

Decreased level of consciousness

potential risk for aspiration

Uncooperative with treatment regime

risk of severe anatomic damage from treatment regime

i.e., Mallory-Weiss tear, rupture of esophagus, aspiration of gastric contents, aspiration of charcoal.

Ingestion of chemicals/medications that can compromise the patient’s central nervous system, cardiac, or respiratory status rapidly.

i.e., tricyclic antidepressants, calcium channel blockers

(16)

Table 2

Suggested Initial Treatment Protocol

	Initiate large bore intravenous line
	Assess glucose via reagent strip (obtain needed blood from IV site)
	Administer Naloxone (Narcan™)

0.4mg to 2.0mg in adults

0.1mg/kg in children

(this can be administered endotracheally if IV access unavailable)

If the glucose is less than 80mg/dl

The patient should be given 1-2 ml/kg of 50% dextrose solution IV.

If IV access is unavailable; 1mg of Glucagon may be given IM route, as it has been documented to reverse hypoglycemia within nine minutes

Glucose should be used with caution in the presence of acute CVA, because studies have shown that supplemental glucose may potentiate the infarct.

Thiamine 100mg IM or IV (diluted) should be administered to all patients with history of alcohol abuse, to aid in the treatment of prevention of Wernicke’s Encephalopathy.

(3, 16)

 Table 3

Factors to be Considered When Deciding on Modality of Gastric Decontamination

	Degree of toxicity of ingested agent
	Formulation and absorption kinetics of the agent
	Elapsed time since ingestion
	Dose ingested
	Presenting signs and symptoms
	Previous medical history
	Special consideration with the following:

Sustained release agents

Enteric coated agents

MAO inhibitors

Caustic agents

Table 4

Ipecac Dosage

15ml orally to Children ages 1-12

* this is controversial, some studies say 30ml for ages 1 and up.

30ml orally ages 13 to adult

Dose can be repeated once, if vomiting has not started 30 minutes post administration of initial dose.

The addition of a large amount of water is also controversial.

 Table 5

Standard dosing of Activated Charcoal

Adults 50 - 100 grams
Children 25 - 50 grams
Infant 1gram/kg

Although the desired ratio of charcoal to toxin is 10:1 (8)

References:

1. Litovitz TL, Bailey KM, Schmitz BF, Holm KC, Klein-Schwartz W. 1990 Annual report of the American association of poison control centers national data collection system. Annals of Emergency Medicine 1991; 9 : 461-509.

2. Caravati EM, McElwee NE. Use of clinical toxicology resources by emergency physicians and its impact on poison control centers.
Annals of Emergency Medicine 1991; 20 :147-150.

3. Kulig K. Initial management of ingestions of toxic substances. The New England Journal of Medicine 1992; 326: 1677-1681.

4. Taylor AS. On poisons in relation to medical jurisprudence and medicine. London, England: John Churchill; 1848.

5. Donovan JW. Selective gastric decontamination in the poisoned patient. Topics in Emergency Medicine 1993; 15: 1-12.

6. Kulig KW, Bar-Or D, Cantril SV, Rosen P, Rumack BH. Management of acutely poisoned patients without gastric emptying.
Annals of Emergency Medicine 1985; 14: 562-567.

7. Merigian KS, Woodard M, Hedges JR, Roberts JR, Stuebing R, Rashkin MC. Prospective evaluation of gastric emptying in the self poisoned patient. Annals of Emergency Medicine 1990; 8: 479-483.

8. Perrone J, Hoffman RS, Goldfrank LR. Special considerations in gastrointestinal decontamination.
Emergency Medicine Clinics of North America 1994; 12: 285-299.

9. Auerbach PS, Osterloh J, Braun G, et .al.. Efficacy of gastric emptying: gastric lavage versus emesis induced with ipecac.
Annals of Emergency Medicine 1986; 15: 692-698.

10. Tenenbein M, Cohen S, Sitar DS. Efficacy of ipecac induced emesis; orogastric lavage and activated charcoal for acute drug overdose. Annals of Emergency Medicine 1987; 16: 838-841.

11. Young WF, Bivins HG. Evaluation of gastric emptying using radionuclides: gastric lavage versus ipecac induced emesis.
Annals of Emergency Medicine 1993; 22: 1423-1427.

12. Tandberg D, Diven BG, McLeod JW. Ipecac induced emesis verses gastric lavage: a controlled study in normal adults.
American Journal of Emergency Medicine 1986; 4: 205-209.

13. Saetta JP, March S, Gaunt ME, Quinton DN. Gastric emptying procedures in the self-poisoned patient: are we forcing gastric contents beyond the pylorus? Journal of the Royal Society of Medicine 1991; 84: 274-276.

14. Harris CR, Filandrinos D. Accidental aspiration of activated charcoal into the lung: aspiration by proxy.
Annals of Emergency Medicine 1993; 22: 1470-1473.

15. Torres A, Serra-Battles J, Ros E, et. al., Pulmonary aspiration of gastric contents in patients receiving mechanical ventilation: the effect of body position. Annals of Internal Medicine 1992; 116: 540-543.

16. Krenzelok EP, Dunmire SM. Acute poisoning emergencies: resolving the gastric decontamination controversy.
Postgraduate Medicine 1992; 91: 179-186.

"Research Applied to Clinical Practice:
Gastric Decontamination in Toxicologic Emergencies: Are We Helping or Hurting?"
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is a webarticle by  Robert C. Knies, RN MSN CEN [bknies@stevenshealthcare.org]
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