Final answer:
The nurse should report the finding of serum potassium 2.8 mEq/L to the provider due to the potential risks of hypokalemia during surgery.
Step-by-step explanation:
The nurse should report the finding of serum potassium 2.8 mEq/L to the provider. This level indicates hypokalemia, which is low potassium in the blood. Hypokalemia can have serious consequences for the patient during surgery, such as abnormal heart rhythms.