The most important action
Thirty-six hours after parathyroidectomy she has perioral numbness and hand cramps with a serum calcium of 7.4 mg/dL, so she has symptomatic hypocalcemia. She also takes digoxin for atrial fibrillation. Intravenous calcium gluconate is given slowly with cardiac monitoring, and the risk is greater in a client taking digoxin, because calcium increases digoxin's effect on the heart and can trigger dangerous arrhythmias. Continuous cardiac monitoring is the most important action during the infusion.
Why hypocalcemia follows parathyroidectomy
After removal of an overactive parathyroid gland, the remaining glands may be suppressed and slow to recover, and bone that was depleted of calcium can take up calcium rapidly. Serum calcium falls, usually within the first few days. Low calcium increases neuromuscular excitability, producing numbness around the lips and fingertips, muscle cramps, positive Chvostek and Trousseau signs, and in severe cases tetany, laryngospasm, and seizures.
The digoxin interaction
Digoxin and calcium both increase the force of cardiac contraction and influence cardiac electrical activity. High calcium levels, especially when rising quickly during an infusion, enhance digoxin's effects and increase the risk of serious arrhythmias. Continuous monitoring allows the nurse to detect bradycardia, new ectopy, or other rhythm changes immediately and stop the infusion. This is why the monitoring answer outranks the others.
| Option | Problem or value |
|---|
| Same line as sodium bicarbonate | Calcium precipitates with bicarbonate; never mixed |
| Continuous cardiac monitoring | Detects arrhythmias, the main danger with calcium and digoxin |
| Rapid push | Can cause bradycardia and arrhythmias; give slowly |
| Calcium every 4 hours | Guides dosing but does not detect arrhythmias |
Why the other options are wrong
Running calcium in the same line as sodium bicarbonate causes precipitation; calcium is also not mixed with phosphate. A rapid push can cause bradycardia, hypotension, and arrhythmias; calcium gluconate is given slowly per protocol. Rechecking calcium every 4 hours is useful for guiding replacement, but laboratory results arrive late and do not detect the arrhythmias that are the immediate danger. The nurse also checks the IV site, because extravasation of calcium can injure tissue.
Exam takeaway
Key point IV calcium plus digoxin means continuous cardiac monitoring. Give calcium slowly and never with bicarbonate or phosphate in the same line.