What magnesium range is associated with cardiac arrest?

What magnesium range is associated with cardiac arrest?

• A. 5-8 mg/dL
• B. 5-10 mg/dL
• C. 8-12 mg/dL
• D. 20-35 mg/dL

Answer: (D)

Magnesium at very high levels suppresses the heart’s electrical activity and can stop the rhythm. Normal serum magnesium is about 1.7–2.2 mg/dL, and therapeutic levels for seizure prevention with magnesium sulfate are around 4–7 mg/dL. As levels climb, you first see signs like slowed reflexes and bradycardia, then progressing conduction problems. Cardiac arrest is linked to extreme hypermagnesemia, typically in the range of about 20–35 mg/dL. That’s because the excessive magnesium markedly depresses myocardial excitability and impulse conduction, leading to arrest if not corrected. In practice, if toxicity is suspected, stop magnesium, monitor closely, administer calcium gluconate as an antidote, and provide supportive care; dialysis may be needed in renal failure.

Magnesium at very high levels suppresses the heart’s electrical activity and can stop the rhythm. Normal serum magnesium is about 1.7–2.2 mg/dL, and therapeutic levels for seizure prevention with magnesium sulfate are around 4–7 mg/dL. As levels climb, you first see signs like slowed reflexes and bradycardia, then progressing conduction problems. Cardiac arrest is linked to extreme hypermagnesemia, typically in the range of about 20–35 mg/dL. That’s because the excessive magnesium markedly depresses myocardial excitability and impulse conduction, leading to arrest if not corrected. In practice, if toxicity is suspected, stop magnesium, monitor closely, administer calcium gluconate as an antidote, and provide supportive care; dialysis may be needed in renal failure.