Are you familiar with gastric lavage, an emergency first-aid technique?

Gastric lavage , also known as Stomach wash,involves instilling a liquid of a specific composition into the stomach cavity to mix with the stomach contents, then withdrawing it. This process is repeat multiple times. Its purpose is to remove unabsorbed toxins or clean the stomach cavity in preparation for gastric surgery or examinations. For acute poisoning such as ingestion of organophosphorus pesticides , inorganic phosphorus , alkaloids , or barbiturates , gastric lavage is an extremely important emergency treatment. There are three types of gastric lavage: induce vomiting lavage , gastric tube lavage , and gastrostomy lavage .

Indications

1. Clears various toxins from the stomach

2. Treatment of complete or incomplete pyloric obstruction

3. Treatment of acute and chronic gastric dilatation

Contraindications

1. Corrosive esophagitis

2. Esophageal and gastric varices

3. Esophageal or cardiac stenosis or obstruction

4. Severe cardiopulmonary diseases

I. Induced vomiting and gastric lavage

Vomiting is the body’s natural defense mechanism to expel toxins from the stomach. Because induced vomiting and gastric lavage are simple and easy to perform, it is an effective self-rescue and mutual-rescue measure for acute poisoning patients who have recently ingested poison and are still conscious (excluding those who have ingested corrosive toxins, petroleum products, or have esophageal varices or upper gastrointestinal bleeding ).

(1) Indications

1. For acutely poison individuals who are conscious, have a vomiting reflex, and are able to cooperate, oral gastric lavage should be encourage as the first-line treatment.

2. The effects of oral poisoning are best within 2 hours.

3. When there is no gastric tube available for on-site self-rescue.

(2) Contraindications

1. Individuals with impaired consciousness.

2. Before convulsions or seizures are control.

3. Patients who are uncooperative and refuse to drink water.

4. Acute poisoning from ingestion of corrosive toxins and petroleum products, etc.

5. Comorbidities include upper gastrointestinal bleeding, aortic aneurysm, and esophageal varices.

6. Pregnant women and the elderly.

(3) Methods

1. First, prepare the patient mentally, explain the requirements and methods in detail, so as to gain their cooperation and facilitate the smooth progress of the procedure.

2. The patient should sit upright and frequently take large amounts of gastric lavage fluid orally, about 400-700 ml, until the patient feels bloated and full.

3. Immediately use a tongue depressor or bamboo chopsticks (both wrapped in gauze) to stimulate the posterior pharyngeal wall of the patient, which will induce reflexive vomiting and expel gastric lavage fluid or gastric contents. Repeat this process several times until the expelled gastric lavage fluid is clear and odorless.

(4) Precautions

1. After inducing vomiting and lavaging the stomach, the patient should be immediately send to a nearby large hospital. Where a gastric tube should be insert for gastric lavage as appropriate.

2. Be careful of aspiration when inducing vomiting and lavaging the stomach, as violent vomiting may induce acute upper gastrointestinal bleeding.

3. It is important to ensure that the amount ingested and the amount vomited are roughly equal.

2. Gastric lavage via gastric tube

Gastric lavage involves inserting a gastric tube through the nose or mouth, down the esophagus, and into the stomach. The poison is first aspirate, follow by the injection of lavage fluid, and then the stomach contents are empty to remove the toxin. Patients who have ingested poison should have a gastric tube inserted for lavage as early as possible, without time constraints. This method is prefer for those who have ingested large amounts of poison within 4-6 hours, as it offers good detoxification and fewer complications. However, since some poisons can remain in the stomach even after six hours, lavage is still necessary in most cases.

Indications

1. For those who do not respond to induced vomiting and gastric lavage, or those with impaired consciousness or who are uncooperative.

2. For patients who need to have gastric fluid samples collected for toxicology analysis, gastric lavage via gastric tube should be the first choice.

3. Gastric lavage should be perform on all patients who have been poison by oral poisons and have no contraindications.

Contraindications

1. Poisoning by strong acids, strong alkalis, and other toxins that have a significant corrosive effect on the digestive tract.

2. Patients with upper gastrointestinal bleeding, esophageal varices, aortic aneurysm, severe heart disease, etc.

3. Those whose convulsions induce by poisoning are not control.

4. In cases of ethanol poisoning, the vomiting reflex is hyperactive, and aspiration is prone to occur when inserting a gastric tube. Therefore, gastric lavage should be use with caution.

Methods

1. Instrument preparation: The treatment tray contains a funnel-shaped gastric lavage tube, forceps, paraffin oil, gauze, kidney dish, cotton swabs, tongue depressor, mouth opener, 1% ephedrine nasal drops, stethoscope, etc., and a measuring cup containing gastric lavage fluid.

2. The patient should be seat or semi-sitting; for those with severe poisoning, the patient should lie on their left side. A waterproof cloth should be place under the chest. If the patient has removable dentures, they should be remove. A bucket of water should be place under the patient’s head on the bed, and a kidney dish should be place at the corner of the patient’s mouth.

3. After applying paraffin oil to the tip of the sterilized gastric tube, hold the tube with gauze in your left hand and wrap it with gauze for 5-6 cm with your right hand. Slowly insert the tube through the nasal cavity or mouth. When the tube is inserted 10-15 cm (to the pharynx), instruct the patient to swallow and gently push the tube forward. If the patient is unconscious, gently lift their head to increase the curvature of the pharynx and quickly insert the tube. When it is inserted to about 45 cm, the tube is in the stomach.

4. If there is impaire consciousness, an oral gag can be use to open the upper and lower teeth, a dental splint can be place, and the nasogastric tube can be slowly insert. Do not force it.

5. If the patient experiences severe coughing, difficulty breathing, or paleness during the insertion of the gastric tube, the gastric tube should be remove immediately. After resting for a while, it should be reinsert to avoid accidental intubation.

More Methods

A. To confirm that the gastric tube has entered the stomach, you can use a syringe to quickly inject air into the gastric tube while listening to the sound of bubbles in the stomach with a stethoscope. This will confirm that the gastric tube is in the stomach cavity.

B. During gastric lavage, first place the funnel below the level of the stomach, squeeze the rubber bulb to remove all stomach contents, and take a sample for testing if necessary.

C. Hold the funnel 30-50cm above your head and slowly pour approximately 300-500ml of gastric lavage fluid into it each time. When a small amount of lavage fluid remains in the funnel, quickly lower it below the stomach level and invert it into a bucket of water to use siphon action to drain the lavage fluid. If drainage is insufficient, squeeze the rubber bulb to draw out more fluid and raise the funnel again to inject more solution. Repeat this lavage process until the lavage fluid is clear and odorless.

D. After gastric lavage, depending on the patient’s condition, an antidote, activate charcoal, or laxative may be inject into the gastric tube. Then, the gastric tube should be fold back and quickly pull out to prevent the liquid inside from entering the trachea.

Commonly used gastric lavage solutions

The temperature of the gastric lavage fluid is generally 35-38℃. Excessively high temperatures can dilate blood vessels, accelerate blood circulation, and promote the absorption of toxins. The dosage is generally 2000-4000 ml.

1. For acute poisoning patients whose nature of the poison is unknown, gastric contents should be extracted and sent for testing. Warm water or physiological saline should be used as the gastric lavage fluid. After the nature of the poison is determined, an antidote should be used for gastric lavage.

2. Sodium bicarbonate solution is generally use for gastric lavage at a concentration of 2% to 4%, often for organophosphate pesticide poisoning, as it can decompose and render the pesticide non-toxic. However, it is contraindicate in cases of trichlorfon poisoning, as trichlorfon can transform into the more toxic dichlorvos in an alkaline environment. Sodium bicarbonate solution can also be use for gastric lavage in cases of arsenic (arsenic trioxide) poisoning.

3. Potassium permanganate solution is a strong oxidizing agent, and is generally use at a concentration of 1:2000 to 1:5000. It is often use as a gastric lavage solution for acute barbiturate poisoning, atropine poisoning, and mushroom poisoning. However, potassium permanganate should not be use for organophosphorus pesticide poisoning with parathion (1605), as it can oxidize it into the more toxic paraoxon (1600).

Precautions

1. Gastric lavage is mostly an emergency measure in critical situations. Emergency personnel must operate quickly, accurately, gently, and nimbly to complete the entire gastric lavage process in order to do their best to save the patient’s life.

2. During gastric lavage, the patient’s vital signs should be monitor at all times. If the patient experiences abdominal pain, discharges bloody lavage fluid, or goes into shock, the gastric lavage should be stop immediately.

3. It is important to maintain a balance between the amount infused and the amount aspirated each time. The amount infused each time should not exceed 500 ml. Excessive infusion can cause acute gastric dilatation , increase intragastric pressure, and increase the absorption of toxins.

4. For any patient whose breathing or heartbeat has stopped, CPR should be performed first, followed by gastric lavage. Before gastric lavage, vital signs should be checked. If there is hypoxia or excessive respiratory secretions, sputum should be suctioned first to maintain a clear airway before performing gastric lavage.

5. If the oral poisoning time is too long (more than 6 hours), hemodialysis treatment may be considered.

Gastric lavage using a lavage device or syringe

After suctioning out the stomach contents using a gastric lavage tube connected to a syringe or lavage device, inject about 300ml to 500ml of gastric lavage fluid, then remove and discard it. Repeat the lavage process until the stomach is clean.

Automatic gastric lavage machine gastric lavage method

Place the prepared gastric lavage solution into a clean solution container (bottle). Submerge one end of the medication tubing in the solution container below the liquid level, and place the other end of the water outlet tubing into the wastewater container (bottle). Connect one end of the gastric tube to the patient’s lavage tube. Adjust the liquid volume, turn on the power, and press the “Start” button. The machine will begin automatically lavaging the stomach. After lavage, press the “Stop” button.

Precautions

Before using an automatic gastric lavage machine, the grounding wire must be properly connected to prevent electric shock. Check that all pipe connections are correct and secure, and that the machine is operating normally. While injecting lavage fluid into the stomach using the control panel, observe the positive pressure gauge (generally, the pressure should not exceed 40 kPa) and the inflow and outflow of the lavage fluid. The gastric lavage machine must be run empty once before use. If the water flow is obstructed or there is a significant difference between the inflow and outflow, adjust the flow using the equalization button. Clean the machine promptly after use.

III. Gastric lavage via laparotomy and gastrostomy

It is used for acute oral poisoning and critical cases where gastric lavage via intubation is truly difficult.

Method: The patient was placed in a supine position, and after routine disinfection and draping, local anesthesia was administered. A 7-8 cm longitudinal incision was made in the upper abdomen to enter the abdominal cavity. A purse-string suture was first made on the anterior wall of the stomach. The stomach wall was then incised, and a [procedure/incision] was inserted.

Insert a suction catheter, aspirate the stomach contents, and repeatedly irrigate. Leave the catheter in place post-procedure for further irrigation if necessary, and also for administering antidotes or nutrients.