Indications and contraindications for gastric lavage

To put it simply, gastric lavage is to clean the toxins in the stomach. Gastric lavage is required when food poisoning or pesticide poisoning occurs. As an important rescue measure, gastric lavage has indications and contraindications. It must be performed under qualified conditions to achieve the desired effect. Contraindications are to exclude unsuitable conditions such as patients with aortic aneurysm. So, what are the indications and contraindications of gastric lavage?

Gastric lavage classification

1. Vomiting and gastric lavage

Vomiting is the body's natural self-defense reaction to expel toxins from the stomach. Because emetic and gastric lavage is simple and easy to perform, it is an effective self-rescue and mutual rescue measure on the spot for patients with acute poisoning who have just taken poison and are conscious (excluding those who have taken corrosive poisons, petroleum products, esophageal varicose veins, upper gastrointestinal bleeding, etc.).

2. Gastric lavage with gastric tube

It is to insert a gastric tube from the nasal cavity or oral cavity, through the esophagus to the stomach, first suck out the poison and then inject gastric lavage fluid, and discharge the stomach contents to achieve the purpose of eliminating the poison. Patients who have ingested poison orally should have a gastric tube inserted and gastric lavage performed as soon as possible if conditions permit, without being restricted by time. For those who have ingested large amounts of poison within 4 to 6 hours, this method of gastric lavage should be the first choice because of its good detoxification effect and relatively few complications.

Indications and contraindications

1. Oral ingestion of toxic substances

Anyone who has orally ingested any toxic substance, such as pesticides, overdose of drugs, or food poisoning, should undergo gastric lavage as soon as possible to quickly remove the poison.

2. Examination or preoperative preparation

Patients with pyloric obstruction and large amounts of gastric fluid retention need to undergo a barium meal examination or preparation before surgery. Those with acute gastric dilatation who need to discharge gastric contents and relieve pressure should have a catheter inserted for suction and lavage.

3. Gastric lavage is contraindicated for patients who have ingested strong corrosives (such as strong acids and alkalis). Gastric lavage should be performed with caution in patients with esophageal varices or aortic aneurysms.

Precautions

1. Gastric lavage is mostly used for acute poisoning, and it is required to vomit out the food quickly, because delay will increase the absorption of poison and endanger life. Therefore, we must fight for time, every second counts, quickly prepare items, and perform gastric lavage immediately.

2. The general principle for gastric lavage is to do it as early as possible. Generally speaking, gastric lavage is most effective within 4 to 6 hours after taking poison. However, for some patients, it has been more than 6 hours since they sought medical treatment. In this case, gastric lavage may still be considered. The following factors may cause the poison to remain in the stomach for a long time: ① The patient has poor gastrointestinal function, causing the poison to remain in the stomach for a long time; ② Reabsorption of the poison after absorption; ③ More poison enters the stomach; ④ Some poisons are absorbed slowly, such as when the poison itself has a capsule shell.

3. Insertion of the catheter into the stomach should be done gently, quickly and skillfully, and lavage should begin after confirming that the catheter has entered the stomach (to extract gastric juice is the most reliable). Be careful not to accidentally insert the catheter into the respiratory tract during lavage. If severe coughing, shortness of breath, or cyanotic struggles occur during intubation, indicating that the tube has been mistakenly inserted into the airway, the tube should be removed quickly and reintubated. Patients who are in a coma or intubated and vomit are prone to aspiration pneumonia and should be cautiously prevented.

4. Warm boiled water is the most commonly used gastric lavage solution, which is effective and safe. 2% sodium bicarbonate solution is often used for poisoning by organophosphorus pesticides, but it should be noted that it should not be used for poisoning by trichlorfon, salicylate and strong acid. 1:5000 potassium permanganate solution has an oxidative detoxification effect on alkaloids and toxic mushroom alkaloids, but it is forbidden to use it for gastric lavage in patients with parathion poisoning. Therefore, the choice of gastric lavage fluid should be considered according to different poisons, and only clean water is the most widely used.

5. The amount of fluid injected each time during gastric lavage should not be too much. Generally, suction should be performed after 300 to 500 ml is injected each time. In particular, when using the positive pressure of an electric motor to deliver gastric lavage fluid, close observation should be made. When it reaches 500 ml, the positive pressure should be turned off and replaced with negative pressure suction. The operator should not open the site immediately after turning on the machine to prevent excessive infusion volume from causing acute gastric dilatation or even gastric perforation. Excessive infusion volume at one time can also easily cause a large amount of poison to enter the intestine, resulting in increased absorption of the poison. When using an electric gastric lavage machine, you should always add gastric lavage fluid to the bottle to avoid sending too much air into the stomach. When performing gastric lavage for ulcer disease combined with throttle obstruction, the lavage volume should be small and the pressure should be low to prevent perforation or bleeding.

6. Gastric lavage will cause certain damage if the poison is highly corrosive, and may cause perforation during intubation. It is generally not advisable to perform gastric lavage, and when a large amount of liquid enters, it is very easy to cause gastric perforation and tearing. Intubation of a seizure-prone patient may induce a seizure. Intubation of comatose patients can easily lead to aspiration pneumonia, so gastric lavage should be performed with caution. If gastric lavage is necessary, the patient should lie flat without a pillow, with the head tilted to one side to prevent suffocation caused by aspiration. Gastric lavage is not recommended for patients with esophageal varices.

7. Water intoxication and electrolyte imbalance: Water intoxication occurs due to excessive water in the body caused by water imbalance due to gastric lavage and other reasons. A large amount of potassium ions and chloride ions are lost during gastric lavage, and excessive sugar input, dehydration treatment and the use of hormones during fluid replacement will often make the loss of potassium ions more serious. Therefore, attention should be paid to hypokalemia and hypochlorite alkali poisoning during gastric lavage.

8. Patients with respiratory arrest or cardiac arrest should first undergo cardiopulmonary resuscitation and then gastric lavage. Vital signs should be checked before gastric lavage. If there is hypoxia or excessive respiratory secretion, sputum should be aspirated first to keep the respiratory tract open before performing gastric lavage. During the gastric lavage process, the patient's vital signs should be observed at all times. If the patient feels abdominal pain, oozes bloody lavage fluid, or shows signs of shock, gastric lavage should be stopped immediately.

9. After the first irrigation, a sample of the extracted fluid should be sent for relevant testing to identify the type of poison and to guide treatment.