Osmotic Diuretics in Pediatrics
Osmotic Diuretics in Pediatrics
Key Points
- Osmotic diuretics are essential agents in managing various pediatric conditions
- Primary mechanism involves increasing osmotic pressure in renal tubules
- Most commonly used agent is Mannitol
- Critical in managing increased intracranial pressure and cerebral edema
Core Principles
Osmotic diuretics function by:
- Creating an osmotic gradient across cell membranes
- Preventing water reabsorption in nephrons
- Promoting excretion of water and electrolytes
- Reducing fluid volume in body compartments
Pharmacological Properties
Mechanism of Action
- Primary Effects
- Increases plasma osmolality
- Creates osmotic gradient in renal tubules
- Expands extracellular fluid volume initially
- Inhibits water and solute reabsorption
- Secondary Effects
- Reduces blood viscosity
- Promotes plasma volume expansion
- Enhances renal blood flow
- Induces release of atrial natriuretic peptide
Pharmacokinetics
- Distribution
- Limited cell membrane penetration
- Primarily remains in extracellular space
- Volume of distribution: 0.5-0.7 L/kg
- Metabolism
- Minimal hepatic metabolism
- Primarily excreted unchanged
- Half-life: 2-4 hours in normal renal function
Clinical Applications
Primary Indications
- Neurological Conditions
- Acute increased intracranial pressure
- Cerebral edema
- Post-traumatic brain injury
- Perioperative neurosurgical cases
- Renal Conditions
- Acute oliguria
- Prevention of acute kidney injury
- Rhabdomyolysis
- Ophthalmologic Conditions
- Acute glaucoma
- Reduction of intraocular pressure
Special Considerations
- Age-specific responses
- Underlying medical conditions
- Fluid status assessment
- Concurrent medications
Administration & Dosing
Mannitol Dosing Guidelines
- Emergency ICP Reduction
- Loading dose: 0.5-1.0 g/kg IV over 20-30 minutes
- Maintenance: 0.25-0.5 g/kg every 4-6 hours
- Maximum daily dose: 6-8 g/kg/day
- Prophylactic Use
- 0.3-0.5 g/kg IV over 15-20 minutes
- Timing: 1-2 hours before intervention
Administration Guidelines
- Preparation
- Verify solution clarity and absence of crystals
- Warm solution if crystallization present
- Use in-line filter for administration
- Route Considerations
- Central line preferred for concentrated solutions
- Avoid extravasation
- Monitor IV site regularly
Monitoring & Complications
Essential Monitoring Parameters
- Fluid Status
- Input/output monitoring
- Daily weights
- Vital signs
- Clinical hydration assessment
- Laboratory Parameters
- Serum electrolytes
- Osmolality
- Renal function tests
- Acid-base status
Potential Complications
- Fluid/Electrolyte Disturbances
- Hyponatremia or hypernatremia
- Hypokalemia
- Dehydration
- Acid-base imbalances
- Cardiovascular Effects
- Volume overload
- Congestive heart failure exacerbation
- Hypotension or hypertension
- Neurological Effects
- Rebound increase in ICP
- Cerebral dehydration
- Seizures
Contraindications
- Absolute
- Active intracranial bleeding
- Severe cardiac failure
- Severe dehydration
- Relative
- Renal failure
- Electrolyte imbalances
- Pulmonary edema
