What action should be taken if a patient's potassium level falls below 3.5?

A potassium level falling below 3.5 is indicative of hypokalemia, which can significantly affect cardiac function. The heart is particularly sensitive to changes in potassium levels because potassium plays a vital role in maintaining the electrical activity of the cardiac cells. When the potassium level is low, patients are at risk for arrhythmias, which can be life-threatening.

Assessing the heart in this situation involves monitoring the patient's heart rate, rhythm, and looking for any signs of arrhythmias or other complications related to low potassium. This assessment may include an electrocardiogram (ECG) to check for characteristic changes associated with hypokalemia, such as flattened T waves or the presence of U waves. Understanding the potential cardiac implications of low potassium levels underscores the priority of heart assessment in this scenario.

While checking blood pressure, administering magnesium, or calling a dietitian may be relevant in different contexts, the immediate action should be to assess the heart, as this is directly related to the risks posed by hypokalemia.