Hypertonic Saline vs Mannitol for ICP Reduction
Comparing hyperosmolar agents for elevated intracranial pressure — pharmacology, administration considerations, and evidence review of 7 key studies.
Jimmy Pruitt
Clinical Pharmacist
7
Studies
2,815+
Patients
4
Meta-Analyses
10
References
Elevated intracranial pressure (ICP) is caused by excess volume in the cerebral spaces, which causes a reduction in the cerebral perfusion pressure and affects blood flow and oxygenation to the brain. Hyperosmolar agents are the cornerstone of acute ICP management.
Osmotic Gradient
HTS and mannitol draw fluid from cerebral space into vasculature across the BBB
Shifting Standard
Mannitol was the gold standard, but HTS has proven at least as effective
Patient-Centered
Agent selection should be based on individual patient factors and comorbidities
Mechanism of Action
Hypertonic Saline
Increases serum sodium levels, creating a gradient for water to follow sodium extracellularly and move out of cerebral spaces into the vasculature. Continuous infusion aids in resuscitation.
Mannitol
Osmotic diuretic — increases osmolality of glomerular filtrate, blocking reabsorption of water and causing excretion of sodium. Moves water to extracellular and vascular spaces.
Dosing
Hypertonic Saline (3–23.4%)
3% NaCl
300–500 mL bolus
or continuous at 100 mL/hr, titrate per response
23.4% NaCl
0.43–0.5 mL/kg
IV bolus, max 30 mL/dose
Mannitol (20% most common)
0.25–1 g/kg
IV bolus q6–8h (Usually 25–100 g per dose)
5–25% solutions available
Administration
Hypertonic Saline
3% — intermittent bolus or continuous infusion
*Strong osmotic gradient not retained with continuous infusions
23.4% — intermittent bolus over 15 min
Mannitol
Intermittent IV infusion over 30 minutes
Adverse Effects
HTS
Mannitol
Critical Cautions
HTS: Central Line Required
Solutions >3–5% require a central line
Mannitol: In-Line Filter Required
Due to risk of crystallization. Avoid in hypovolemia and anuria.
Patient Population
HTS
Hypovolemic, hypotensive, traumatic resuscitation
Mannitol
Euvolemia, hypertensive, fluid restrictions
Monitoring
Serum Na (HTS)
145–155 mEq/dL
Serum Osmolality
300–320 mOsm/L
Titrate both agents based on ICP
Clinical Pearl
Consider the adverse effects of each agent and the comorbidities for an individual patient rather than making a simple comparison in efficacy of hypertonic saline versus mannitol.
| Parameter | 3% NaCl | 23.4% NaCl | 20% Mannitol |
|---|---|---|---|
| Vascular Access | Peripheral or Central | Central ONLY | Peripheral or Central |
| Volume/Dose | 500 mL+ | ~30 mL | 125–500 mL |
| Equipment | Bolus: Gravity Continuous: IV pump |
Syringe pump preferred | IV infusion pump |
Evidence at a Glance
Study Types
Largest Studies
Outcome Consistency
Consensus
HTS = Mannitol
Both effective for ICP reduction. No significant mortality or neuro outcome differences.
| Author/Year | Design (n) | Intervention | Key Outcomes |
|---|---|---|---|
| Kerwin, 2009 | Retrospective n=22 |
HTS vs mannitol for mean ICP reduction in TBI | HTS ≥ mannitol for ICP in severe TBI |
| Li, 2015 | Meta-Analysis 7 studies, n=169 |
HTS vs mannitol in mean ICP reduction in TBI | HTS more effective than mannitol in TBI |
| Burgess, 2016 | Meta-Analysis 7 trials, n=191 |
HTS vs mannitol: ICP, treatment failure, mortality, neuro outcomes | No diff. mortality/neuro↓ ICP failure w/ HTS |
| Berger-Pelleiter, 2016 | Meta-Analysis 11 studies, n=1,820 Largest |
HTS vs mannitol: mortality, ICP, functional outcomes | No sig. reduction in mortalityNo diff. functional outcomes |
| Pasarikovski, 2017 | Systematic Review 5 studies, n=175 |
HTS vs mannitol in ICP for aneurysmal SAH | No difference in aSAH |
| Gu, 2018 | Meta-Analysis 12 RCTs, n=438 |
HTS vs mannitol: ICP, control, Na/osmolality, mortality, neuro function | No diff. ICP/mortality/neuroHTS preferred in refractory ICP |
Bottom Line
Hypertonic saline has proven to be at least as effective as mannitol at reducing ICP. The choice between agents should be guided by individual patient factors rather than a simple efficacy comparison.
Both agents are effective for ICP reduction with no significant differences in mortality or neurological outcomes.
HTS may have an advantage in TBI patients with refractory intracranial hypertension and may reduce ICP treatment failure rates.
Consider patient comorbidities and volume status: HTS for hypovolemic/hypotensive patients; mannitol for euvolemic/hypertensive patients.
Monitor serum osmolality (300–320 mOsm/L) and titrate based on ICP for both agents.
- Burgess S, et al. Annals of Pharmacotherapy. 2016;50(4):291–300.
- Li M, et al. Medicine. 2015;9(4):17.
- Dastur C, et al. Stroke and Vascular Neurology. 2017;2:21–29.
- Kerwin A, et al. J Trauma. 2009;67:277–282.
- Pasarikovski C, et al. World Neurosurg. 2017;105:1–6.
- Gu J, et al. Neurosurg Rev. 2018;42:499.
- Berger-Pelleiter E, et al. CJEM. 2016;18:112–120.
- Farrokh S, et al. Curr Opin Crit Care. 2019;25:105–109.
- Witherspoon B, et al. Nurs Clin N Am. 2017;52:249–60.
- Micromedex [Electronic]. Greenwood Village, CO: Truven Health Analytics.
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