Final answer:
The nursing priority is to hold the Lasix dose and notify the physician about the patient's critical low potassium level to avoid exacerbating hypokalemia, which is life-threatening.
Step-by-step explanation:
The nursing priority is to hold the dose and notify the physician about the patient's low potassium level (K+ 2.0). Administering Lasix without addressing the hypokalemia could further lower the potassium levels and exacerbate the patient's condition.
Potassium is an essential electrolyte vital for many bodily functions, including heart rhythm regulation. The normal potassium levels in the blood are generally between 3.5 and 5.0 milliequivalents per liter (mEq/L). A level of 2.0 mEq/L, as shown in the patient's labs, indicates severe hypokalemia, which can be life-threatening and lead to arrhythmias. Lasix (furosemide) is a loop diuretic that helps the body get rid of excess fluid by increasing urine production; however, it can also cause the excretion of potassium, further lowering its levels.
Therefore, the priority is to correct the potassium level, likely with supplementation, before administering a diuretic that could worsen the hypokalemia. The BNP level is high, which indicates heart failure and supports the use of Lasix, but not until the risk of hypokalemia is addressed. Assessing the patient for edema is also important, but not as immediate a concern as the critical potassium level.