What are the benefits of intravenous magnesium sulfate infusion for controlling cerebral edema and hypertension after a cerebral vascular accident (CVA)?

From the Guidelines

Intravenous magnesium sulfate infusion is not recommended for controlling cerebral edema and hypertension after a cerebral vascular accident (CVA) due to lack of benefit in terms of outcomes, as shown in recent meta-analyses 1. The use of intravenous magnesium sulfate has been studied in the context of cerebral vasospasm and delayed cerebral ischemia (DCI) after aneurysmal subarachnoid hemorrhage (aSAH), with preclinical data suggesting potential benefits in improving cerebral blood flow (CBF) and decreasing vasospasm. However, clinical evidence, including two meta-analyses of available randomized controlled trials (RCTs), has found no benefit in terms of cerebral infarction or reduced mortality 1. Some key points to consider when evaluating the use of intravenous magnesium sulfate infusion include:

• The concentration of magnesium in the cerebrospinal fluid (CSF) may be more important than peripheral circulation levels, but this has yet to be validated 1.
• The peak risk for DCI and cerebral vasospasm is postbleed days 6 to 10 after aSAH, and prophyltic hemodynamic augmentation has been studied as a potential approach, but with no difference in DCI found 1.
• Other treatments, such as angioplasty and vasodilator therapy, may offer benefits in improving perfusion and reducing vasospasm, but require careful consideration of potential complications and risks 1. Overall, the current evidence recommends against the routine use of magnesium sulfate to improve neurological outcomes for patients with aSAH, and alternative treatments should be considered for controlling cerebral edema and hypertension after a CVA.

From the Research

Benefits of Intravenous Magnesium Sulfate Infusion

• The infusion can reduce the incidence of cerebral vasospasm in patients with aneurysmal subarachnoid hemorrhage (SAH) 2.
• It does not seem to exacerbate the duration of electrolyte disturbance associated with aneurysmal subarachnoid hemorrhage 3.
• Magnesium sulfate infusion can control hypertensive peaks during cardiopulmonary bypass (CPB) as efficiently as nicardipine 4.
• It has a relaxing effect on smooth vascular muscles, which can help decrease mean arterial pressure (MAP) and systemic vascular resistance (SVR) 4.

Effects on Cerebral Edema and Hypertension

• There is no direct evidence from the provided studies on the effect of intravenous magnesium sulfate infusion on controlling cerebral edema after a cerebral vascular accident (CVA).
• However, the reduction in cerebral vasospasm and control of hypertensive peaks may indirectly help in reducing cerebral edema and hypertension 2, 4.

Safety and Efficacy

• Magnesium sulfate infusion is safe and does not seem to exacerbate electrolyte disturbances in patients with aneurysmal SAH 3.
• The infusion can be effective in reducing the incidence of cerebral vasospasm, but no benefit is found regarding improved favorable functional outcome or reduction of mortality 2.
• The use of magnesium sulfate in the treatment of refractory convulsive status epilepticus has insufficient evidence, with only case reports available 5.