Mannitol 20% Infusion Time for ICP Management
For a 200ml dose of Mannitol 20% in this 63kg patient with elevated ICP, infuse over 15-20 minutes. This is the guideline-recommended administration time for mannitol at the standard dose of 250 mOsm used for intracranial pressure reduction 1, 2.
Dosing Verification
Your ordered dose of 200ml of 20% mannitol equals 40 grams, which translates to 0.63 g/kg for this 63kg patient 1, 2. This falls appropriately within the recommended range:
- Standard dosing range: 0.25-1.0 g/kg 3, 1, 2
- Most commonly recommended: 0.25-0.5 g/kg 1, 2
- For acute herniation crisis: up to 0.5-1 g/kg may be appropriate 3, 2
Administration Protocol
Infusion time: 15-20 minutes for the standard 250 mOsm dose 1, 2. The American College of Anaesthesia specifically recommends this timeframe for mannitol 20% at 250 mOsm (0.25-1.0 g/kg) 1.
Alternative timing considerations:
- Routine ICP management: 20-30 minutes is acceptable 3, 4
- Acute herniation: may give over 15 minutes for larger doses (0.5 g/kg) 3
- Research supports infusion times of 10-30 minutes as effective 4
Critical Monitoring Requirements
Before and during administration:
- Insert urinary catheter before giving mannitol due to osmotic diuresis 3, 2
- Monitor serum osmolality to ensure it remains below 320 mOsm/L 3, 1, 2
- Maintain cerebral perfusion pressure (CPP) between 60-70 mmHg 1, 2
- Use a filter for administration; do not use solutions containing crystals 3
Expected Response
- Onset of action: 10-15 minutes after administration 2
- Peak effect: occurs shortly after completion of infusion 3
- Duration of effect: 2-4 hours 2
- Maximum ICP reduction: typically occurs within 45 minutes 5
Important Clinical Caveats
Volume management is critical: Mannitol induces significant osmotic diuresis requiring volume compensation 1, 2. With normal renal function, this patient will require aggressive fluid replacement with crystalloids to prevent hypovolemia 1.
Repeat dosing: Can be given every 6 hours as needed, with a maximum daily dose of 2 g/kg 2. Monitor serum osmolality before each dose 1, 2.
Adjunctive measures: Use mannitol in conjunction with other ICP control measures including head-of-bed elevation, sedation/analgesia, normocapnia (PaCO2 34-38 mmHg), and cerebrospinal fluid drainage if available 3, 1.