Salt or Sugar for Your Injured Brain?
Background. Rising intracranial pressure (ICP) is a poor prognostic indicator in traumatic brain injury (TBI). Both mannitol and hypertonic sodium solutions are used to treat raised ICP in patients with TBI.
Objective. This meta-analysis compares the use of mannitol versus hypertonic sodium solutions for ICP control in patients with TBI.
Data Sources and Study Eligibility. Randomised clinical trials in adults with TBI and evidence of raised ICP, which compare the effect on ICP of hypertonic sodium solutions and mannitol.
Methods. The primary outcome measure is the pooled mean reduction in ICP. Studies were combined using a Forest plot.
Results. Six studies were included, comprising 171 patients (599 episodes of raised ICP). The weighted mean difference in ICP reduction, using hypertonic sodium solutions compared with mannitol, was 1.39 mm Hg (95% CI −0.74 to 3.53).
Limitations. Methodological differences between studies limit the conclusions of this meta-analysis.
Conclusions. The evidence shows that both agents effectively lower ICP. There is a trend favouring the use of hypertonic sodium solutions in patients with TBI.
Rationale. Intracranial pressure (ICP) has been shown to be a more powerful predictor of neurological deterioration than cerebral perfusion pressure in patients with brain injury, when measured by subsequent Glasgow Outcome Score. Mannitol, a sugar solution used as an osmotic diuretic, is recommended by the Brain Trauma Foundation and by the European Brain Injury Consortium for the treatment of raised ICP, but its propensity to cross the blood–brain barrier and cause a rebound rise in ICP, coupled with potential problems in patients with hypovolaemic trauma, remain concerns. Hypertonic sodium solutions are also used to lower ICP, but are less likely to cross the blood–brain barrier and are therefore less likely, in theory, to cause a rebound rise in ICP. The literature is unclear as to whether mannitol or hypertonic sodium solutions are more effective. This lack of consensus is due, in most part, to the lack of well-designed and sufficiently powered studies directly comparing the two agents. ICP is usually only measured in an intensive care unit and so the evidence for the choice of osmotherapeutic agent is derived from research within this setting. However, as a rising ICP will adversely affect patient outcomes, expert opinion recommends that clinical evidence of rising ICP should trigger measures to reduce the ICP even before quantitative monitoring can be started. ICP measurement, although not entirely patient centred as an outcome measure, does suggest itself as the most viable, sensitive surrogate outcome marker for patient morbidity and mortality.
Objectives. This meta-analysis combines randomised clinical trials in adults receiving mannitol or hypertonic sodium solutions for the treatment of raised ICP after traumatic brain injury (TBI). The primary outcome measure is the difference in mean ICP reduction between the groups treated with hypertonic sodium solution and those treated with mannitol. This report conforms to the recommendations of the PRISMA statement on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
Abstract and Introduction
Abstract
Background. Rising intracranial pressure (ICP) is a poor prognostic indicator in traumatic brain injury (TBI). Both mannitol and hypertonic sodium solutions are used to treat raised ICP in patients with TBI.
Objective. This meta-analysis compares the use of mannitol versus hypertonic sodium solutions for ICP control in patients with TBI.
Data Sources and Study Eligibility. Randomised clinical trials in adults with TBI and evidence of raised ICP, which compare the effect on ICP of hypertonic sodium solutions and mannitol.
Methods. The primary outcome measure is the pooled mean reduction in ICP. Studies were combined using a Forest plot.
Results. Six studies were included, comprising 171 patients (599 episodes of raised ICP). The weighted mean difference in ICP reduction, using hypertonic sodium solutions compared with mannitol, was 1.39 mm Hg (95% CI −0.74 to 3.53).
Limitations. Methodological differences between studies limit the conclusions of this meta-analysis.
Conclusions. The evidence shows that both agents effectively lower ICP. There is a trend favouring the use of hypertonic sodium solutions in patients with TBI.
Introduction
Rationale. Intracranial pressure (ICP) has been shown to be a more powerful predictor of neurological deterioration than cerebral perfusion pressure in patients with brain injury, when measured by subsequent Glasgow Outcome Score. Mannitol, a sugar solution used as an osmotic diuretic, is recommended by the Brain Trauma Foundation and by the European Brain Injury Consortium for the treatment of raised ICP, but its propensity to cross the blood–brain barrier and cause a rebound rise in ICP, coupled with potential problems in patients with hypovolaemic trauma, remain concerns. Hypertonic sodium solutions are also used to lower ICP, but are less likely to cross the blood–brain barrier and are therefore less likely, in theory, to cause a rebound rise in ICP. The literature is unclear as to whether mannitol or hypertonic sodium solutions are more effective. This lack of consensus is due, in most part, to the lack of well-designed and sufficiently powered studies directly comparing the two agents. ICP is usually only measured in an intensive care unit and so the evidence for the choice of osmotherapeutic agent is derived from research within this setting. However, as a rising ICP will adversely affect patient outcomes, expert opinion recommends that clinical evidence of rising ICP should trigger measures to reduce the ICP even before quantitative monitoring can be started. ICP measurement, although not entirely patient centred as an outcome measure, does suggest itself as the most viable, sensitive surrogate outcome marker for patient morbidity and mortality.
Objectives. This meta-analysis combines randomised clinical trials in adults receiving mannitol or hypertonic sodium solutions for the treatment of raised ICP after traumatic brain injury (TBI). The primary outcome measure is the difference in mean ICP reduction between the groups treated with hypertonic sodium solution and those treated with mannitol. This report conforms to the recommendations of the PRISMA statement on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses.
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