What is gastric lavage?
"Gastric lavage" and "gastrolusi" are two terms extracted from medical language to indicate a forced process of emptying the stomach from its contents: we are talking about a therapeutic method to be carried out purely in case of "emergency, very different from" physiological "vomiting or self-induced.
Purpose of the intervention
The goal for which a gastric lavage is carried out is easily understood: to extract the generally toxic or extremely dangerous content from the stomach.
In any case, gastric lavage is not performed for the sole purpose of eliminating toxic substances: in fact, some surgical procedures require the complete emptying of the stomach before subjecting the patient to the operation.
It is necessary to point out that gastric lavage must be carried out within a short time from the ingestion of the harmful or toxic substance, in order to avoid its absorption (usually 1-2 hours): if the substance exceeds the limit of the pyloric sphincter, the its absorption cannot be avoided by gastric lavage.
Effectiveness
There are divergent opinions about the efficacy of gastric lavage carried out one "hour after" ingestion of food / harmful substance: more precisely, the term "efficacy" - in this specific case - refers to the validity of gastrolusis in detoxify the intestinal tract. It is believed, in fact, that after this period of time the intestine has already absorbed part of the dangerous substance. [From General and clinical pharmacology, by B. G. Katzung]
How it is done
First of all, before subjecting the patient to gastric lavage it is advisable to draw up a "medical history of the subject, in order to evaluate the indications and contraindications of the procedure; moreover, it is necessary to carefully protect the airways if the patient is in a state of unconsciousness.
When the subject is forced to undergo an endotracheal intubation, gastric lavage can be performed using a nasogastic or oro-gastric tube.
Gastric lavage is not a practice of great executive difficulty: the patient - conscious state - must be positioned, on a generally inclined bed, in left lateral decubitus, so that the probe can be facilitated to collect the gastric contents piled up near the great curvature of the stomach: moreover, during the execution of the practice, the lateral position of the patient reduces the possibility that the lavender liquid passes into the intestine through the pylorus. If the patient is intubated, he must be placed in the supine position.
The probes are made of a transparent material, with some large lateral orifices towards the end; the length is generally 1.2 meters and the diameter, which varies according to the gastric contents, can sometimes be larger than one centimeter. Clearly, in case of ingestion of toxic liquids, the probe can also have a thinner diameter.
After the introduction of the probe into the gastric pouch, we proceed with the aspiration of what is present in the stomach: this procedure must continue until the stomach is completely empty.
Finally, the washing of the stomach: s "0.2 liters of liquid are introduced and removed in the adult and 0.1 liters in the child (up to the age of 10). The liquid in question can be water (less frequently) or physiological solution heated to body temperature to prevent hypothermia: when necessary, specific antidotes can be added to the liquid.
Gastric lavage must continue until a clear, limpid liquid with no solid material comes out of the probe: at this point, we proceed with a further washing (1-10 liters).
Finally, to avoid a possible aspiration of the liquid, the probe, before being removed, must be closed or stapled carefully.
At the end of gastric lavage, the patient should ingest activated charcoal. [adapted from "Clinical Toxicology Guidelines ", Pavia Poison Control Center "]
Alternatives to gastric lavage
Noticeably less invasive than gastric lavage (and, according to the thought of some toxicologists, even more effective than the forced gastric emptying method) is the administration of activated carbon, capable of ensuring excellent adsorption of toxic and drugs. Activated carbon must not be used in case of poisoning by corrosive or alkaline acid mineral, nor is it capable of binding lithium, iron and potassium. However, it has recently been observed that activated carbon exerts an even greater efficacy than gastric lavage.
Even the administration of substances with a strongly purgative action could assist in the elimination of the toxic from the gastrointestinal tract, thus reducing its absorption.
[adapted from General and clinical pharmacology, by B. G. Katzung]
Contraindications
Gastric lavage cannot be practiced in some specific cases: absolutely banned in case of poisoning by corrosive agents or caustic substances (eg derived from petroleum) and surfactants (responsible for the production of abnormal quantities of foam). If the patient suffers from epilepsy or has lost consciousness, gastric lavage can only be performed by using precise precautions.
Summary
Gastric lavage: to fix concepts
Therapeutic method to be carried out purely in case of "emergency, very different from" physiological "vomiting
- Forced removal of stomach contents, generally toxic or extremely dangerous for the patient's survival
- Prepare the stomach for an upcoming surgery
- Draw up a "history of the subject
- Carefully protect the airways in case the patient is unconscious
- Place the patient on the table in a lateral (if not intubated) or supine (if intubated) position
- Introduction of the probe into the stomach
- Aspiration of gastric contents
- Introduction of 0.2-0.1 liters of washing liquid (water-physiological solution at room temperature) → leakage of clear liquid
- Additional wash (1-10 liters)
- Closing / stapling the probe
- Probe extraction
- Administration of activated charcoal
- Administration of activated vegetable carbon only → contraindications: does not bind lithium, iron, potassium; useless in case of ingestion of corrosive agents
- Administration of purgatives
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