Gastric lavage should not be considered one of the routine decontamination methods in toxicology. Its considerations include various potential complications, scarce evidence, and uncertain clinical effects. Volunteers and animal studies show a decreased absorption of poisons and certain markers; however, high-quality clinical studies are lacking.
Gastric lavage may be considered within 1 hour of oral intake of a significant amount of a life-threatening toxic substance. It should be restricted to life-threatening exposure in airway-protected patients. Examples include ingestion of significant amounts of tricyclic antidepressants, labetalol, organophosphates, or toxic alcohols.
Poisoning with corrosives (risk of gastrointestinal perforation); poisoning with volatile substances, hydrocarbons, or detergents (high risk of aspiration); significant risk of gastrointestinal bleeding; unconscious patients (unless intubated); significant psychomotor agitation, patient refusal, lack of cooperation, or resistance.
The patient should be fully awake and cooperative to perform this procedure; otherwise, the patient’s airway must be secured with endotracheal intubation. Proactive endotracheal intubation must be sought in every case.
Large-bore nasogastric/orogastric tube coated with a lubricant gel (eg, lidocaine gel), funnel, bucket, 50 mL syringe.
1. Insert the nasogastric/orogastric tube into the stomach, then confirm placement (see Nasogastric/Orogastric Tube Insertion). A fully awake patient should be placed in the left lateral decubitus position. An intubated patient may lie supine.
2. Introduce 200 to 300 mL of water at body temperature into the tube and then lower the tube into the bucket below the level of the stomach before water disappears from the funnel. This will cause the water to return (siphon phenomenon). Repeat until clear (watery) outflow is seen.
3. A single dose of activated charcoal (1 g/kg) can be administered into the stomach after completing gastric lavage as indicated. Exceptions include substances that do not get adsorbed by activated charcoal (alcohols, mercury, lead, iron, caustics, and hydrocarbons).
Consider administration of repeated doses of activated charcoal (starting from 1 g/kg and followed by 0.5-1 g/kg every 2-4 hours) in patients who ingested life-threatening doses of quinine, dapsone, phenobarbital, carbamazepine, or theophylline.