A 32-year-old multigravida at 36 weeks gestation presents to the labor and delivery unit with complaints of severe headache and blurred vision. Her blood pressure is 180/115 mmHg, and she has 4+ proteinuria. The physician has ordered magnesium sulfate therapy. What is the priority nursing intervention before initiating magnesium sulfate?

• 1. Verify Antidote Availability: Physically check that a vial of calcium gluconate and a syringe are at the bedside.
• 2. Establish Baseline Assessments: Assess and document deep tendon reflexes (DTRs), respiratory rate, oxygen saturation, and level of consciousness. These will be monitored hourly.
• 3. Ensure Monitoring Equipment: Confirm that a continuous pulse oximeter and an infusion pump are functioning and programmed correctly.
• 4. Patient Education: Instruct the patient to immediately report any feeling of warmth, flushing, nausea, or muscle weakness, which can be early signs of toxicity.

Serial assessments during the infusion are vital. The earliest sign of magnesium toxicity is the loss of deep tendon reflexes (areflexia). The nurse should hold the infusion and notify the provider immediately if DTRs are absent, respirations are less than 12 per minute, or urine output falls below 30 mL/hour.