When administering digoxin, which vital sign is critical to assess?

When administering digoxin, assessing the heart rate is critical because digoxin is a cardiac glycoside that affects the heart's contractility and rhythm. Monitoring the heart rate helps to ensure the patient is not experiencing bradycardia, as digoxin can potentially slow the heart rate. If the heart rate is too low (typically below 60 beats per minute for adults), administering digoxin could lead to further bradycardia and increase the risk of adverse effects such as dizziness, fatigue, or more severe complications like heart block.

In patients receiving digoxin, it is also important to be aware of any changes in rhythm, such as atrial fibrillation or atrial flutter, since the medication is often used to control these conditions. Therefore, continuous or frequent monitoring of the heart rate is essential to ensure the safe administration of digoxin, making it the most critical vital sign to assess in this context.