What are the guidelines for NPO (Nil Per Os) in a diabetic patient undergoing surgery?

NPO Guidelines for Diabetic Patients Undergoing Surgery

Diabetic patients may drink clear fluids before hospital admission and should have their NPO status managed according to the number of meals they will miss, with glucose infusion only necessary when oral feeding resumption is delayed. 1

Preoperative NPO Management Based on Timing

Single Meal Missed (Morning Admission)

• Clear fluids are permitted before hospital admission even when the morning meal is skipped 1
• If surgery is short and patient leaves PACU before 10 AM, breakfast is served immediately and morning medications are taken at that time 1
• No glucose infusion is required in this scenario 1
• Diabetic patients should be given priority on the surgical list to minimize fasting time 1

Extended NPO (PACU Discharge 10 AM - Noon)

• Patient should not take usual morning medication before hospital but takes it on arrival 1
• Glucose infusion (10% dextrose at 40 mL/h) is initiated on arrival to the ambulatory surgery unit 1
• Infusion must continue until the next meal if treatment includes insulin or insulin secretagogues (sulfonylureas or glinides) 1

Prolonged NPO (PACU Discharge After Noon)

• Patient should eat a light breakfast including solids before coming to hospital 1
• Morning medications are taken before hospital arrival 1
• Peripheral IV line is inserted but glucose infusion is not necessary 1

No Meal Missed

• If surgery is scheduled so no meals are missed, treatment continues as usual and patient eats breakfast normally 1

Perioperative Glucose Monitoring During NPO Status

• Monitor blood glucose at least every 2-4 hours while patient is NPO 1, 2
• Target glucose range is 100-180 mg/dL within 4 hours of surgery 1, 2
• Capillary blood glucose should be measured on arrival to the surgical unit with a target of 5-10 mmol/L (90-180 mg/dL) 1
• Administer short- or rapid-acting insulin as needed to maintain target range 1, 2

Critical Medication Adjustments Related to NPO Status

Insulin Management

• Give half of NPH dose or 75-80% of long-acting analog on the morning of surgery 1
• Reduce basal insulin by 25% the evening before surgery to achieve better perioperative control with lower hypoglycemia risk 2
• Insulin pumps should be maintained until patient arrives in the surgical unit 1
• Never allow insulin deficiency in Type 1 diabetics, as ketoacidosis develops within hours 1

Oral Hypoglycemic Agents

• Hold metformin only on the day of surgery (not the evening before as historically practiced) 1, 3
• Discontinue SGLT2 inhibitors 3-4 days before surgery to prevent life-threatening euglycemic diabetic ketoacidosis 1, 2, 3
• Hold all other oral agents on the morning of surgery 1, 3

Common Pitfalls to Avoid

• Never pursue glucose targets <100 mg/dL perioperatively, as stricter targets increase hypoglycemia without improving outcomes 2
• Never initiate preoperative glucose infusion in non-insulin-treated patients unless oral feeding resumption is delayed 1
• Never use correction-only insulin without basal insulin in general surgery patients, as basal-bolus regimens reduce complications 1, 2
• Avoid prolonged preoperative fasting whenever possible, as this complicates glucose management 4

Intraoperative Management During NPO

• Measure blood glucose hourly during lengthy procedures 1
• If blood glucose exceeds 16.5 mmol/L (297 mg/dL), surgery should be postponed and corrective insulin administered 1
• Maintain target range of 100-180 mg/dL throughout the procedure 1, 2

Postoperative Resumption of Oral Intake

• Resume oral feeding as soon as possible after surgery 1
• Continue blood glucose monitoring every 2-4 hours until eating resumes 1, 2
• If glucose remains ≤10 mmol/L (180 mg/dL), resume regular treatments at usual times 1
• If glucose exceeds 10 mmol/L (180 mg/dL), patient should remain hospitalized for corrective subcutaneous insulin boluses 1