What are the immediate steps to take when black gastric content is observed from a Gastrostomy (G)-tube?

Black Gastric Content from G-Tube: Immediate Management

Black gastric content from a G-tube represents upper gastrointestinal bleeding until proven otherwise and requires immediate assessment of hemodynamic stability, followed by upper endoscopy if the patient is stable or CT angiography if unstable. 1

Immediate Assessment

Hemodynamic Evaluation

• Calculate the shock index (heart rate ÷ systolic blood pressure): If >1, the patient is hemodynamically unstable and requires urgent intervention 2, 3, 4
• Check vital signs, orthostatic changes, and signs of active bleeding (hematemesis, melena) 5
• Measure hemoglobin and assess for acute drop (mean decrease in G-tube bleeding is 3.69 g/dL, range 0.9-6.8 g/dL) 5

Determine Bleeding Source

• Black gastric content indicates upper GI bleeding, most commonly from gastric ulceration caused by pressure from the internal bumper or balloon against the gastric wall 1, 6
• Bleeding typically presents within 28 hours of tube placement (range: immediately to 3 days), but can occur at any time with chronic tubes 5
• Other presentations include hematemesis, melena, hematochezia, or bloody drainage through the tube 5

Management Algorithm

For Hemodynamically Stable Patients (Shock Index ≤1)

• Perform upper endoscopy within 24 hours to visualize the gastric mucosa under the internal bolster and identify ulceration or erosion 1, 3
• Examine for excessive tension between internal and external bolsters, which causes pressure necrosis 1, 6
• Immediately loosen the external fixation plate to eliminate traction and reduce pressure on the gastric wall 1
• Initiate proton pump inhibitor therapy to reduce gastric acid secretion 1
• Consider gastric decompression if gastroparesis or increased gastric pressure is present 1

For Hemodynamically Unstable Patients (Shock Index >1)

• Perform CT angiography immediately as first-line investigation (sensitivity 79-95%, specificity 95-100%) without waiting for bowel preparation 2, 3, 4
• If CTA is negative, proceed directly to upper endoscopy, as 10-15% of apparent lower GI bleeding originates from upper GI sources 1, 2, 3
• Transcatheter arterial embolization (TAE) is the definitive treatment if active bleeding is identified on angiography 5
• Surgical exploration is reserved for patients with persistent bleeding despite TAE or when endoscopic/radiologic interventions fail 4, 5

Specific Interventions

Conservative Management (Mild Bleeding)

• Transfusion with restrictive strategy (hemoglobin trigger 70 g/L, target 70-90 g/L unless cardiovascular disease present) 2, 3
• Compression of the gastrostomy site may achieve hemostasis in select cases 5
• Ensure proper tension between bolsters—avoid excessive tightness that causes pressure necrosis 1, 6

Interventional Management (Moderate to Severe Bleeding)

• Angiography with TAE is safe and effective for hemostasis when conservative management fails 5
• Prophylactic or therapeutic TAE achieved successful hemostasis in 75% of cases in one series 5
• Endoscopic therapy alone is often temporary and may require angiographic embolization for definitive control 7

Surgical Management (Refractory Bleeding)

• Wedge resection including the tube insertion site when bleeding focus cannot be identified on angiography or endoscopy 5
• Exploration for persistent bleeding despite TAE or when patient remains unstable after aggressive resuscitation 4, 5

Critical Pitfalls to Avoid

• Do not delay imaging in unstable patients while attempting conservative measures—CTA should be performed immediately 2, 3, 4
• Do not assume the bleeding is minor based on appearance alone—gastric ulceration from G-tube pressure can cause life-threatening hemorrhage 6, 5
• Do not maintain excessive tension on the external bolster—this is the primary cause of pressure-induced gastric ulceration 1, 6
• Do not place nasogastric tubes routinely—they do not reliably aid diagnosis, do not affect outcomes, and cause complications in one-third of patients 1, 3

Prevention Strategies

• Avoid excessive lateral traction on the tube and tension between internal and external bolsters 1
• Regularly inspect the gastric mucosa under the internal bolster during endoscopic evaluations 1
• Ensure the external fixation plate is subjected to very low traction without tension immediately after placement 1
• Monitor for risk factors including malnutrition, poor wound healing, and significant weight gain 1