A diabetic patient who uses insulin to control blood glucose has been NPO since midnight before having a mastectomy. The nurse will anticipate the need to

• A. withhold the usual scheduled insulin dose because the patient is NPO.
• B. obtain a blood glucose measurement before any insulin administration.
• C. give the patient the usual insulin dose because stress will increase the blood glucose.
• D. administer a lower dose of insulin because there will be no oral intake before surgery.

Answer: (B)

Before giving insulin to an NPO patient, you must first check the current blood glucose. Measuring the glucose level guides whether insulin is needed and at what dose, because being NPO changes how insulin and glucose balance with no oral intake, and surgery itself can raise glucose due to stress hormones.

If the glucose is within the target range, you can proceed with the appropriate plan for that level; if it’s high, a corrective dose may be needed; if it’s low, you would hold or adjust insulin to prevent hypoglycemia. Relying on the usual pre‑NPO dose without checking the actual value risks dangerous hypo- or hyperglycemia.

Other options assume a fixed approach without confirming the patient’s current glucose, which can lead to inappropriate dosing when the patient is fasting and undergoing surgery.