TPN is often decreased or stopped before to anesthesia, largely to minimize difficulties caused by high (hyperosmolarity) or fast drop (hypoglycemia) infusion rates in the busy operational arena. However, because sudden cessation might result in severe hypoglycemia, TPN must be progressively reduced. Patients should be made aware of the risk of hypoglycemia and instructed on how to treat it (glucagon, glucose tablets). Once patients are stable on a lower dose for 2-3 days, TPN can be discontinued entirely. If patient does not receive any glucose for more than 24 hours, he/she will become hypoglycemic and require treatment. The key to prevent this from happening is to continue TPN even after surgery since insulin remains in their body for several days even after stopping the infusion. In conclusion, TPN administration requires special attention since its interruption or decrease may lead to hyperglycemia or hypoglycemia. Anesthesiologists must be aware of this fact so that they can manage these complications appropriately.