Final answer:
The nurse should expect to administer Magnesium sulfate.
Step-by-step explanation:
Based on the Mg level of 3.1 mEq/L, the nurse should expect to administer Magnesium sulfate to the patient. Magnesium sulfate is a medication used to treat patients with low levels of magnesium in their blood, which is indicated by a Mg level below the normal range of 1.7-2.2 mEq/L. It helps to restore the balance of magnesium in the body and is commonly administered intravenously.