What is the recommended intravenous (IV) fluid replacement for a patient with a high output ileostomy?

Intravenous Fluid Replacement for High Output Ileostomy

The recommended intravenous fluid replacement for patients with high output ileostomy is normal saline (0.9% sodium chloride) at 2-4 L/day, which should be administered while keeping the patient nil by mouth initially to demonstrate that output is driven by oral intake. 1

Initial Assessment and Management

Step 1: Rule Out Other Causes

Before attributing high output solely to the ileostomy, exclude:

• Intra-abdominal sepsis
• Partial/intermittent bowel obstruction
• Enteritis (e.g., Clostridium, Salmonella)
• Recurrent disease in remaining bowel
• Abrupt discontinuation of medications (e.g., steroids, opiates)
• Use of prokinetics 1, 2

Step 2: Initial IV Fluid Resuscitation

• Begin with intravenous normal saline (2-4 L/day)
• Keep patient nil by mouth for 24-48 hours to break the cycle of thirst-driven drinking 1
• Target urine output ≥800 mL/day with urinary sodium >20 mmol/L 1, 2
• Monitor for fluid overload, which can readily cause edema due to high circulating aldosterone levels 1

Step 3: Laboratory Monitoring

• Serum electrolytes (sodium, potassium)
• Renal function (urea, creatinine)
• Magnesium levels
• Urinary sodium (random urinary sodium <20 mmol/L suggests sodium depletion) 2

Transitioning from IV to Oral Fluids

After 2-3 days of IV saline administration:

1. Gradually withdraw intravenous saline
2. Reintroduce food and restricted oral fluids
3. Implement the following oral regimen:

• Restrict oral hypotonic fluids (water, tea, coffee, fruit juices, alcohol) to <500 ml daily 1, 2
• Provide glucose-saline solution with sodium concentration ≥90 mmol/L (1-2L daily) 1, 2

Recommended Oral Rehydration Solutions

Solution	Components
Modified WHO cholera solution	Sodium chloride: 60 mmol (3.5 g) Sodium bicarbonate: 30 mmol (2.5 g) Glucose: 110 mmol (20 g) Water: 1 liter
Alternative solution	Sodium chloride: 120 mmol (7 g) Glucose: 44 mmol (8 g) Water: 1 liter

1, 2

Adjunctive Medications to Reduce Output

• Loperamide: 2-8 mg before meals (first-line, can increase up to 12-24 mg in severe cases) 2
• Codeine phosphate: 30-60 mg four times daily (can be added to loperamide for synergistic effect) 1, 2
• For high output (>2 L/day):
  • Proton pump inhibitors (e.g., omeprazole 40 mg daily)
  • H2 antagonists (e.g., ranitidine 300 mg twice daily) 1, 2
• For severe refractory cases: Consider octreotide 2

Electrolyte Management

• Hypokalemia: Usually secondary to sodium depletion with hyperaldosteronism. Correct sodium/water depletion first 1
• Hypomagnesemia: Initially with IV magnesium sulfate, then oral magnesium oxide and/or 1-alpha-calcidol 1, 2
• Note: Hypokalaemia may be resistant to potassium treatment but responds to magnesium replacement 1

Long-term Management Considerations

• Regular monitoring of weight, hydration status, and electrolytes 2
• Consider home IV hydration protocols for newly created ileostomies to prevent readmissions due to dehydration 3
• Target total fluid intake of 2-2.5 liters daily, with increased amounts during hot weather or exercise 2

Common Pitfalls to Avoid

• Encouraging excessive oral hypotonic fluid intake, which paradoxically worsens sodium losses 1, 2
• Inadequate dosing of antimotility medications 2
• Failure to correct hypomagnesemia when managing hypokalemia 1
• Administering excessive IV fluids, which can cause edema due to high aldosterone levels 1
• Not restricting oral hypotonic fluids once IV therapy is discontinued 1, 2

By following this algorithm, you can effectively manage fluid replacement in patients with high output ileostomy, reducing morbidity and improving quality of life.