Gastric Lavage (Stomach Wash) - Forensic Medicine

Definition

Indications / Time Window

• Indicated in patients who present within 3 hours of ingestion of poison.
• Can be performed when gastric secretions are present, gastric emptying is delayed, or sustained-release medications were ingested.
• Gastric lavage beyond 6-12 hours is still recommended for ingestion of: salicylates, tricyclics, carbamazepine, and barbiturates (due to their delayed gastric emptying).
• Parikh's states it may be life-saving if undertaken within 4-6 hours of poison ingestion.

Gastric Lavage Tube (Equipment)

• Soft, non-collapsible rubber tube
• 36-40 French size in diameter
• 1.5 m in length
• Glass/filter funnel at upper end
• Suction bulb at midpoint to pump out stomach contents
• Rounded, blunt, perforated lower end (multiple side openings)
• Mark at 50 cm from the lower end (distance from lips to cardiac stomach in adults ~45 cm)

Procedure (Step by Step)

1. Patient Positioning

• Left lateral (recovery) position OR prone/semiprone with hips higher than head and face pointing downward so the mouth is at a lower level than the larynx.
• This prevents aspiration of regurgitated fluid into the respiratory tract.
• Dentures must be removed.
• A mouth gag with a central hole is inserted (especially in unconscious patients) to prevent the tube being bitten through.

2. Tube Insertion

• Lubricate the lower end with glycerin, Vaseline jelly, liquid paraffin, glycerine, milk, or similar substance.
• Pass the tube through the hole in the mouth gag, over the tongue, down the oesophagus.
• In adults, insert up to 50 cm; in children, up to 25 cm.

3. Confirming Tube Position in Stomach

• Stethoscope method: Inject a puff of air - bubbling sounds heard over the stomach confirm correct placement.
• Water test: Dip the upper end in a cup of water - if the tube is in the trachea, air bubbles will emerge. A hissing noise at the funnel end also suggests tracheal placement.

4. Initial Washings

• Instill 250-300 mL of warm (35°C) saline or plain water by holding the funnel above the patient's mouth level (gravity flow).
• In children: use 10-15 mL/kg body weight of warm saline (NOT plain water - risk of hyponatremia and water intoxication).
• Lower the funnel below the level of the stomach over a receptacle to siphon out gastric contents.
• Using too much fluid for the first wash may sweep poison onwards into the duodenum.

5. Subsequent Washings

• Repeat with 500 mL of fluid (warm water or specific antidote solution).
• Continue until the returning fluid is clear, odourless, colourless, and free of particulate matter.
• At the end, a small quantity of activated charcoal (1 g/kg body weight) suspension and/or an ionic cathartic is left in the stomach.

Lavage Fluids - Specific Antidotes for Different Poisons

Complications of Gastric Lavage

1. Laryngeal spasm
2. Aspiration pneumonitis
3. Perforation of stomach or oesophagus
4. Sinus bradycardia and ST elevation on ECG

Contraindications of Gastric Lavage

Absolute Contraindications

1. Corrosive poisoning (except carbolic acid) - risk of perforation
2. Convulsant poisons - risk of precipitating convulsions
3. Comatose patient - risk of aspiration
4. Volatile poisons - risk of inhalation
5. Hypothermia - body temperature must be addressed first

Note from Parikh's: In strychnine (convulsant) poisoning, convulsions should be controlled before lavage; in kerosene/volatile poisons or comatose states, the airway must first be secured with a cuffed endotracheal tube.

Relative Contraindications

1. Alimentary tract diseases (e.g., oesophageal varices)
2. Comatose patients
3. Ingestion of alkali
4. Advanced pregnancy
5. Haemorrhagic diathesis
6. Recent surgical operation (history)

Contraindications to Emesis (for Comparison)

Key Forensic Points to Remember

• First washing is preserved for chemical analysis - medicolegally important.
• Gastric lavage is part of decontamination of the body from ingested poisons; the other methods are: emesis, catharsis, activated charcoal, whole bowel irrigation.
• Ewald or Boas tube = the standard tube used.
• 50 cm = insertion depth in adults; 25 cm in children.
• Warm water (35°C) is the standard lavage fluid; specific antidote solutions are added based on the poison.
• Even after lavage, an antidote should be given - some poisons are secreted back into the stomach after systemic absorption.