What is the correct technique for performing gastric lavage?

Gastric Lavage Procedure Technique

Gastric lavage should be performed using a large-bore orogastric tube (36-40 French), with the patient positioned in the left lateral decubitus position with head-down tilt, using warm tap water in 200-300 mL aliquots with epigastric massage, though this procedure is rarely indicated in modern toxicology practice. 1, 2, 3

Patient Positioning and Airway Protection

• Position the patient in left lateral decubitus with 15-20 degree head-down (Trendelenburg) tilt to minimize aspiration risk and prevent gastric contents from passing into the duodenum 4, 3
• Intubate patients with altered mental status, unprotected airway, or seizures before attempting lavage to prevent aspiration pneumonitis 3
• Ensure adequate sedation if the patient is combative, as proper positioning is essential to avert complications 5

Equipment and Tube Selection

• Use a large-bore orogastric tube (36-40 French in adults, 24-28 French in children) rather than nasogastric tubes, as larger diameter tubes are necessary for removing pill fragments and debris 3
• Smaller nasogastric tubes are inadequate for effective gastric decontamination 3
• Prepare suction equipment, lubricant, and lavage fluid before beginning 3

Lavage Fluid and Technique

• Use warm tap water (38-40°C) rather than room temperature saline, as warm water significantly improves pill removal and is equally safe regarding electrolyte disturbances 2, 6
• Tap water is preferred over 0.9% normal saline as there is no difference in electrolyte profiles post-lavage, and tap water is more cost-effective 6
• Instill 200-300 mL aliquots in adults (10-15 mL/kg in children, maximum 100 mL per aliquot) 3

Two-Phase Lavage Protocol

Phase 1 - Traditional Lavage:

• Instill lavage fluid and immediately aspirate using gravity drainage or gentle suction 2, 3
• Continue until return fluid is clear, typically requiring 2-3 liters total volume 3

Phase 2 - Enhanced Removal:

• Use larger aliquots of warm water with repetitive manual compression/massage of the epigastrium to dislodge adherent pills and improve removal efficacy 2
• This mechanical agitation dramatically improves pill removal compared to traditional technique alone 2

Lavage Methods Comparison

• Double syringe method is fastest (one syringe instilling while the other aspirates), though all methods remove approximately 80-85% of liquid gastric contents 4
• Single syringe method is least well-tolerated by patients 4
• Closed gravity drainage systems are intermediate in speed and tolerability 4

Critical Timing and Indications

• Lavage is only effective if performed within 1 hour of ingestion, though may provide some benefit up to 3-4 hours post-ingestion 1
• Strict indications: Recent ingestion (<1 hour) of potentially life-threatening toxin in patients with obtundation, unprotected airway, seizures, or substances forming concretions 3
• For acetaminophen overdose, activated charcoal (1 g/kg orally) is preferred and can be given after lavage without reducing N-acetylcysteine efficacy 1

Specific Toxin Considerations

Mushroom poisoning (Amanita phalloides):

• Perform gastric lavage followed by activated charcoal via nasogastric tube if patient presents within hours to one day of ingestion with severe GI symptoms 1
• Administer penicillin G (300,000-1 million units/kg/day IV) and silymarin (30-40 mg/kg/day) after decontamination 1

Absolute Contraindications

• Caustic ingestion (acids or alkalis) - lavage may worsen esophageal perforation 3
• Hydrocarbon ingestion (unless containing highly toxic substances) 3
• Unprotected airway in obtunded patients 3
• Prolonged time since ingestion (>4 hours) with minimal expected benefit 1, 3

Post-Lavage Management

• Administer activated charcoal (1 g/kg) with cathartic after completing lavage 3
• Remove the tube after flushing with water 7
• Monitor for complications including aspiration, esophageal perforation, tracheal intubation, electrolyte imbalance, and hypothermia 3

Common Pitfalls

• Using room temperature water without mechanical agitation makes pill removal nearly impossible 2
• Attempting lavage in unintubated patients with altered mental status risks fatal aspiration 3
• Performing lavage beyond 1-4 hours post-ingestion provides minimal benefit and exposes patients to unnecessary morbidity 4, 5
• The routine use of gastric lavage is no longer recommended due to limited outcome data and increased morbidity; it should be reserved for specific life-threatening ingestions presenting early 5