A nurse is caring for a client at 32 weeks gestation who is experiencing preterm labor. The client has been receiving magnesium sulfate for tocolysis for the past 8 hours. Which nursing intervention is the highest priority?

Monitoring deep tendon reflexes and respiratory rate is the highest priority to detect magnesium toxicity early, which can cause respiratory depression and loss of reflexes. Other interventions are important but secondary to preventing life-threatening complications.

Core Nursing Explanation Key Concept Analysis: This question tests the priority nursing action for a patient receiving Magnesium sulfate (MgSO4) for Preterm labor tocolysis. Magnesium sulfate acts as a central nervous system depressant and smooth muscle relaxant. While effective in stopping uterine contractions, its therapeutic range is narrow, and toxicity can lead to life-threatening Respiratory depression and cardiac arrest. Therefore, vigilant monitoring for signs of toxicity is the paramount nursing responsibility.

Answer Rationale: Key Point! The highest priority is always patient safety, specifically preventing life-threatening complications. Option ②, "Monitor deep tendon reflexes (DTRs) and respiratory rate every hour," directly addresses the primary risk of magnesium sulfate therapy. DTRs are a sensitive early indicator of magnesium toxicity (they become hypoactive or absent), and respiratory rate monitoring is critical because severe toxicity causes respiratory muscle paralysis. This intervention aligns with the nursing process of ongoing Assessment to detect complications before they escalate.

Distractor Analysis:
• Watch out for confusion! Option ①: Encouraging ambulation is generally contraindicated for a patient in preterm labor on tocolysis. Bed rest is typically prescribed to reduce uterine activity. Furthermore, while preventing Deep vein thrombosis (DVT) is important for immobilized patients, it is not the highest priority when a patient is on a medication with a high risk of respiratory arrest.
• Option ③: Calcium gluconate is the antidote for magnesium sulfate toxicity. It is administered only when signs of life-threatening toxicity (e.g., respiratory depression, loss of DTRs) are present. Prophylactic administration is incorrect and could be harmful.
• Option ④: While magnesium sulfate can cause flushing and a feeling of warmth, leading to fluid loss, and adequate hydration is important, monitoring for dehydration is a secondary concern compared to the immediate risk of respiratory depression. Fluid overload could also be a concern.

Related Concepts: The core principle here is Therapeutic Drug Monitoring and knowing the specific toxic effects and antidote for high-alert medications. This scenario integrates knowledge of obstetric nursing (preterm labor management) and pharmacology (magnesium sulfate). Concept Summary • Drug: Magnesium Sulfate – A tocolytic and anticonvulsant (used for preeclampsia/eclampsia). • Primary Use in this Context: Suppress uterine contractions (tocolysis). • Major Toxicity Risk: Respiratory depression, loss of deep tendon reflexes, cardiac arrest. • Key Monitoring Parameters (The "Mag Check"): Respiratory rate > 12/min, presence of patellar (knee-jerk) reflex, Urine output > 30 mL/hr (renal excretion is primary route). • Antidote: Calcium Gluconate (10% solution), kept at bedside. Side-by-Side Comparison!

Assessment Finding	Indicates	Nursing Action
DTRs 2+ (normal), RR 16/min	Therapeutic level	Continue monitoring per protocol.
DTRs 1+ (diminished), RR 14/min	Early toxicity	Notify provider, consider holding next dose, increase monitoring frequency.
DTRs absent, RR < 12/min	Severe toxicity	STAT: Stop MgSO4 infusion, administer Calcium Gluconate per order, prepare for respiratory support.

Anatomy, Physiology & Pharmacology Points • Mechanism of Action: Magnesium sulfate competes with calcium at the neuromuscular junction, decreasing acetylcholine release and reducing muscle excitability. This relaxes uterine smooth muscle (tocolytic effect) but also affects skeletal and respiratory muscles. • Excretion: Almost exclusively renal. Impaired kidney function drastically increases toxicity risk. • Clinical Correlation: The loss of DTRs precedes respiratory depression, making it a crucial early warning sign. Memory Tips • Mnemonic for MgSO4 Monitoring: "Reflexes, Respiration, Renal output" – The 3 R's of Magnesium. • Think: "No reflex, no breath." If the knee-jerk is gone, the next step could be the diaphragm stopping. • Calcium Gluconate is the "Calcium to the rescue" antidote because it antagonizes magnesium's effects at the neuromuscular junction. High-Frequency NCLEX Topics This is a classic High Yield NCLEX question. It tests: 1. Priority Setting (Safety first!). 2. Knowledge of High-Alert Medications. 3. Application of the Nursing Process (Assessment before intervention). 4. Obstetric Emergencies (Preterm labor, preeclampsia). Watch Out for Question Variations! • The same drug, different context: "A nurse is caring for a client with severe preeclampsia on MgSO4..." – The priority monitoring (DTRs, RR, UOP) remains identical. • Shift from monitoring to intervention: "The client's respiratory rate is 10/min and DTRs are absent. What is the nurse's immediate action?" (Answer: Stop the MgSO4 infusion and prepare Calcium Gluconate). • Lab value focus: "Which serum magnesium level requires immediate intervention?" (Answer: A level > 8 mEq/L indicates toxicity; therapeutic range is typically 4-8 mEq/L).

Nursing Clinical Practice Guide Clinical Scenario: You are the nurse on the labor and delivery unit. Your patient, Anna, is 32 weeks pregnant with twins and has been on a magnesium sulfate infusion for 6 hours for preterm labor. She mentions feeling very warm and drowsy.

Nursing Intervention Strategy: 1. Assessment: First, perform your scheduled "Mag check." Use a reflex hammer to check the patellar reflex. Count her respirations for a full minute—don't estimate. Check her urine output via Foley catheter (should be >30 mL/hr). Assess level of consciousness. 2. Action: If DTRs are present but diminished (1+) and respirations are 14, notify the provider of these early signs. Do not wait for them to worsen. If your assessment reveals absent reflexes and respirations of 10/min, this is an emergency. Follow your facility's protocol: stop the infusion immediately, call a rapid response, and administer calcium gluconate as ordered. 3. Patient Safety and Precautions: Always have calcium gluconate drawn up and ready at the bedside. Ensure emergency equipment (bag-valve-mask, suction) is functional and nearby. Use an IV pump for the infusion to control the rate precisely. Educate the patient and family about the reason for frequent checks.

Nursing Procedure & Medication Flow • Procedure: Hourly "Mag Check": 1. Introduce yourself and explain the procedure. 2. Assess DTRs: Position patient comfortably. Tap the patellar tendon. Grade the reflex (0=absent, 1+=diminished, 2+=normal, 3+=brisk, 4+=clonus). 3. Count Respirations: Observe chest rise for 60 seconds after taking pulse, so the patient is unaware. 4. Review Urine Output: Document output from the last hour. 5. Document: Record all findings clearly. Report abnormal findings immediately. • Medication: Calcium Gluconate Administration: Given IV push slowly over 5-10 minutes. Rapid administration can cause bradycardia, hypotension, or cardiac arrest. Monitor the IV site for infiltration—it can cause severe tissue necrosis.

A Word from Your Senior Nurse "Magnesium sulfate is one of those drugs where your vigilance literally saves lives. It's not just a task on your checklist; it's your primary defense against a respiratory arrest on the unit. When you're checking those reflexes, you're not just tapping a knee—you're assessing the function of her nervous system. When you count those breaths, you're ensuring her diaphragm is still working. This is the essence of nursing surveillance. On the NCLEX, they want to know you understand that monitoring is an intervention, and often the most critical one. Carry that mindset to the bedside, and you'll be an outstanding nurse."