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Myths of Toxicology: Gastric Lavage

Gussow, Leon MD

doi: 10.1097/01.EEM.0000340950.69012.8d
Toxicology Rounds

“Maybe I shouldn't have given the guy who pumped my stomach my phone number, but who cares? I'd thrown up scallops and Percodan on him the night before in the emergency room. I thought it would be impolite to refuse to give him my number. He probably won't call, anyway.”

Carrie Fisher, from her novel “Postcards from the Edge

Ever since 1822 when the British surgeon Edward Jukes ingested tincture of opium and then washed out his own stomach with a 1?2-inch tube, gastric lavage has been considered a viable option when treating toxic ingestions. After all, the concept has a certain amount of face validity. A patient has swallowed a poison; it's in the gastrointestinal tract. Why wouldn't it be beneficial to remove as much as possible? This reasoning seems so logical it's easy to believe that in certain circumstances gastric lavage must be the standard of care.

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Unfortunately — or fortunately, depending on your point of view — decades of research have not been able to demonstrate any clinical benefit from lavage. Multiple volunteer studies have shown that when lavage is done at 30 or 60 minutes after ingestion of a marker, 50 percent at most is recovered. After one hour, as the marker passes through the pylorus into the small intestine, the amount that can be recovered becomes even smaller. Because most toxicology patients do not present to the emergency department within an hour of ingestion, the majority would not be expected to derive even theoretic benefit from lavage.

Results of clinical studies have been disappointing. Over the past 25 years, there have been several large trials that attempted to evaluate the value of gastric emptying. The first and most influential of these was done at Denver General Hospital by Kulig et al. (Ann Emerg Med 1985;14[6]:562.) This was a large trial, with 592 oral drug overdose patients enrolled. Patients were treated with gastric emptying plus activated charcoal or charcoal alone. The authors concluded that emergency department gastric emptying was not beneficial, with the possible exception of a very small subgroup: those who were obtunded and presented within one hour of an acute ingestion.

Unfortunately, the Kulig study had a number of limitations and flaws that made it impossible to draw any definite conclusions from the data. The group of obtunded patients who presented early was quite small (19), and the subgroup analysis appeared to be done post-hoc. More importantly, although the authors claimed that their study was randomized, in fact it was not. Patients were assigned to a treatment group according to an alternate-day protocol; those presenting on odd-numbered days were given gastric emptying plus activated charcoal, while those presenting on even-numbered days were given charcoal only. Because the purpose of randomization is to avoid bias before the patient is assigned to a treatment group — just as the purpose of blinding is to avoid bias after assignment — a protocol that openly predetermines patients' assignments even before they are enrolled in the study has serious methodological problems.

Two other large studies of clinical outcomes following gastric lavage also had significant limitations, and were unable to demonstrate that the procedure was beneficial. In fact, one of the studies found that lavage was associated with an increased incidence of aspiration when compared with charcoal alone. (Am J Emerg Med 1990;8[6]:479.) The inconvenient truth is that gastric lavage, despite its history of extensive use, is a completely unproven treatment.

The complications and adverse effects of lavage are well known, however. Aside from aspiration, these include perforation of the esophagus or stomach, laryngospasm, hypoxia, and misplacement of the lavage tube into the respiratory tract. In addition, because lavage consumes time and staff resources, it can divert attention from more urgent matters concerning the poisoned patient and others in the emergency department. I know of one case where staff was so involved in lavaging a patient with severe tricyclic antidepressant overdose that they did not notice widening of the QRS interval on the cardiac monitor until ventricular fibrillation ensued.

Taking all these concerns into account, the American Academy of Clinical Toxicology and the European Association of Poisons Centres and Clinical Toxicologists recently published a position paper on gastric lavage that all but throws the procedure under the bus. (J Toxicol Clin Toxicol 2004;42[7]:933.) The conclusion: “Based on experimental and clinical studies, gastric lavage should not be performed routinely, if ever. In certain cases where the procedure is of attractive theoretical benefit (e.g., recent ingestion of a very toxic substance), the substantial risks should be weighed carefully against the sparse evidence that the procedure is of any benefit.”

The take-home lesson for clinicians: No situation mandates that lavage is the standard of care. There are certainly a number of reasonable toxicologists who would not recommend lavage under any circumstance. For most toxins, administration of activated charcoal is an easier and safer procedure for gastrointestinal decontamination. Adhering to a “no lavage, no way” rule will free the clinician to attend carefully to aspects of patient care that are actually important, and minimize the chance of spending the remainder of his shift covered in Percodan and partially digested scallops.

© 2009 Lippincott Williams & Wilkins, Inc.