From the Guidelines
Magnesium sulfate should only be used in refractory cardiac arrest when torsades de pointes is present, as it may help prevent the reinitiation of this specific type of polymorphic ventricular tachycardia associated with a long-QT interval [ 1, 1 ].
Key Points
- The routine use of magnesium for cardiac arrest is not recommended in adult patients, as it has not been shown to increase return of circulation, survival, or neurological outcome [ 1, 1 ].
- Magnesium may be considered for torsades de pointes, with a recommended dose of 1 to 2 g diluted in 10 mL D5W 1.
- The use of magnesium for torsades de pointes is supported by observational studies, but there are no published randomized controlled trials 1.
- Other antiarrhythmic drugs, such as amiodarone or lidocaine, may be considered for VF/pVT that is unresponsive to defibrillation, but magnesium is not a first-line treatment 1.
Clinical Considerations
- Magnesium sulfate should only be used in the context of torsades de pointes, as it is not effective in terminating irregular/polymorphic VT in patients with a normal QT interval 1.
- The decision to use magnesium sulfate should be based on the presence of torsades de pointes, rather than the presence of cardiac arrest alone 1.
The FDA Drug Labels for magnesium sulfate (IV) do not address this question.
From the Research
Use of Magnesium Sulfate in Refractory Cardiac Arrest
The use of magnesium sulfate in refractory cardiac arrest is a topic of interest, with several studies investigating its efficacy.
- The study by 2 found no significant differences in return of spontaneous circulation (ROSC), admission to the hospital, or hospital discharge between patients treated with magnesium sulfate and those treated with placebo.
- A systematic review by 3 found limited data on the role of magnesium in cardiac arrest, making it impossible to recommend for or against its administration during or early after resuscitation.
- The study by 4 found no significant differences in ROSC or discharge from hospital alive between patients treated with magnesium sulfate and those treated with placebo.
- The randomised trial by 5 found no significant differences in return of spontaneous circulation, survival to 24 hours, survival to hospital discharge, or neurological outcome between patients treated with magnesium and those treated with placebo.
Specific Scenarios
- In the case of refractory ventricular fibrillation, the study by 6 describes a successful treatment with magnesium sulfate in an anesthetized dog, but this is not directly applicable to human patients.
- The studies by 2, 4, and 5 provide evidence on the use of magnesium sulfate in human patients with refractory cardiac arrest, but the results are inconsistent and do not provide clear guidance on its use.
Key Findings
- The current evidence does not support the routine use of magnesium sulfate in refractory cardiac arrest.
- More research is needed to determine the efficacy of magnesium sulfate in specific scenarios, such as refractory ventricular fibrillation.
- The use of magnesium sulfate should be considered on a case-by-case basis, taking into account the individual patient's circumstances and the available evidence.