Management of Elevated Intracranial Pressure in Renal Failure
In patients with renal failure and elevated intracranial pressure, hypertonic saline (3% or 23.4% NaCl) is the preferred osmotic agent over mannitol, which carries significant risk of acute renal failure and volume complications in this population. 1, 2, 3
Initial Conservative Measures (Implement Immediately)
Elevate the head of the bed to 30 degrees with the neck in neutral midline position to improve jugular venous outflow and lower ICP, but ensure the patient is not hypovolemic first as this can drop cerebral perfusion pressure 1, 2
Correct factors that exacerbate cerebral edema immediately: treat hypoxemia, hypercarbia, and fever aggressively to normal levels, as fever independently worsens intracranial hypertension 1, 2
Restrict free water and avoid hypotonic fluids that worsen cerebral edema; use isotonic or hypertonic maintenance fluids only 1, 2
Avoid sodium nitroprusside and other cerebral vasodilators for blood pressure control, as these increase ICP 4, 1, 2
Provide adequate sedation and analgesia using short-acting agents (propofol, etomidate, or midazolam for sedation; morphine or alfentanil for analgesia) to allow frequent neurological assessments 2
ICP Monitoring Strategy
Place fiberoptic ICP monitors or ventricular catheters in patients with clinical deterioration or high suspicion of elevated ICP 1
Target ICP <20-25 mm Hg and maintain cerebral perfusion pressure (CPP) >50-60 mm Hg, ideally >70 mm Hg 1, 5
While no randomized controlled trial has demonstrated efficacy of ICP monitoring in intracerebral hemorrhage specifically, it provides crucial physiological information to guide therapy 1
Osmotic Therapy: Critical Decision Point for Renal Failure Patients
Hypertonic Saline (PREFERRED in Renal Failure)
Administer 23.4% saline 30-60 mL IV bolus as first-line osmotic therapy for elevated ICP in patients with renal failure 2, 3
Hypertonic saline avoids the volume depletion, renal failure risk, and rebound intracranial hypertension associated with mannitol 2, 3
In a retrospective cohort of 6 end-stage renal disease patients with 11 ICP crisis events, 23.4% saline reduced ICP from 41 ± 3.8 mmHg to 20.8 ± 3.9 mmHg within 1 hour (p=0.05), with clinical reversal in 55% of events and no cases of pulmonary edema, volume overload, or arrhythmia 3
Alternative concentrations include 3% saline, which provides longer duration of ICP control compared to mannitol 1
Monitor serum sodium closely; expect increases from approximately 141 to 151 mmol/L within 24 hours after bolus 3
Mannitol (Use With Extreme Caution or Avoid)
If mannitol must be used despite renal failure, administer 0.25-0.5 g/kg IV over 20 minutes, repeated every 6 hours as needed, but monitor osmolal gap rather than serum osmolality alone 1, 6, 7
Mannitol carries FDA contraindications including well-established anuria due to severe renal disease and severe dehydration 6
In patients with normal baseline renal function, acute renal failure developed after total mannitol doses of 1171 ± 376 g, but in those with underlying renal compromise, renal function worsened after only 295 ± 143 g total dose 7
Acute oliguric renal failure typically develops within 3.5 days after receiving daily doses of 189 ± 64 g 7
The pathogenesis involves renal vasoconstriction from high mannitol concentrations, which may be averted by monitoring the osmolal gap (target <55 mOsm/kg water) rather than serum osmolality alone 7, 8
Volume overload risk necessitates dialysis to remove excess fluid in patients with renal impairment 4
Renal Replacement Therapy Considerations
If hemodialysis is required, use continuous renal replacement therapy (CRRT) rather than intermittent hemodialysis to minimize ICP fluctuations 4, 9, 10
Intermittent hemodialysis causes ICP elevation and neurological deterioration through dialysis disequilibrium syndrome, with ICP fluctuations correlated to fluid amount and frequency of dialysis 9, 10
In a series of 5 renal failure patients with intracranial hemorrhage, ICP elevated during intermittent hemodialysis resulting in severe brain swelling, with 4 of 5 patients dying from this complication 9
Machine hemofiltration increased mean ICP from 9 ± 1.4 mmHg to 13 ± 1.8 mmHg within the first hour and reduced cerebral perfusion pressure by up to 30%, whereas continuous arteriovenous hemofiltration showed no increase in ICP 10
Do not perform hemodialysis during active ICP crisis; stabilize ICP first with osmotic therapy 9, 3
When continuous RRT is used, both continuous and intermittent RRT can lead to changes in intracranial pressure, but the risk is higher with intermittent RRT 4
Advanced Interventions for Refractory Elevated ICP
Ventriculostomy with CSF drainage is effective for lowering ICP, particularly when hydrocephalus is present 1
Decompressive craniectomy may be considered for refractory intracranial hypertension in supratentorial hemorrhage, with decompressive suboccipital craniectomy specifically recommended for cerebellar swelling with brainstem compression 1
Blood Pressure and Cerebral Perfusion Management
Maintain adequate intravascular volume before initiating vasopressors to ensure optimal cerebral perfusion pressure 1, 2, 5
CPP-guided therapy targeting CPP >70 mm Hg is recommended, though concern exists that blood pressure elevation to maintain CPP may worsen intracranial hypertension 1, 5
Use continuous arterial blood pressure monitoring when administering intravenous vasopressors 5
Carefully titrate fluid intake to output to avoid hypovolemia while preventing volume overload that worsens cerebral edema 2, 5
Interventions NOT Recommended
Do not use the following interventions, as they lack efficacy or cause harm in elevated ICP management: 1, 2
- Hyperventilation (no survival benefit, may worsen cerebral edema through hypoxia)
- Corticosteroids (not effective in cryptococcal or hepatic causes of elevated ICP) 4
- Furosemide as monotherapy
- Prophylactic hypothermia
- Barbiturates
Critical Monitoring Parameters
Neurological assessments every 1-2 hours using GCS and NIHSS 2
Monitor electrolytes, renal function, and serum osmolality every 6 hours during osmotic therapy 2, 7
Continuous blood pressure and CPP monitoring with strict fluid balance 2, 5
Temperature control: aggressively treat fever as it worsens intracranial hypertension and is an independent prognostic factor 2
Key Pitfalls to Avoid
Never use mannitol without monitoring osmolal gap in renal failure patients; the gap should remain <55 mOsm/kg water to prevent mannitol-induced acute renal failure 7, 8
Avoid starch-containing fluids entirely, as they are nephrotoxic and worsen acute kidney injury 2
Do not perform intermittent hemodialysis during active elevated ICP; use CRRT instead to avoid dialysis disequilibrium syndrome 9, 10
Discontinue all nephrotoxic medications immediately including NSAIDs, aminoglycosides, and contrast agents 2