What type of fluids should be given to a diabetic patient who is NPO (nothing by mouth) in the perioperative period?

Perioperative Fluid Management for NPO Diabetic Patients

Administer intravenous dextrose-containing fluids (equivalent to 4 g/hour of glucose) combined with continuous IV insulin infusion to maintain blood glucose between 5-10 mmol/L (0.9-1.8 g/L or 90-180 mg/dL) in all diabetic patients who are NPO during the perioperative period. 1

Fluid Selection and Administration

Primary Fluid Regimen

• Give IV glucose at 4 g/hour continuously when insulin is required, using dextrose-containing solutions (typically 5% or 10% dextrose) 1
• Use 0.9% normal saline as the base fluid for initial hydration and volume replacement, particularly in hyperglycemic patients 2
• All solutes may be used in the perioperative period, including Ringer lactate 1

Critical Principle: Never Give Insulin Without Glucose

• Insulin must always be administered in association with IV glucose to prevent hypoglycemia 1
• The glucose infusion provides substrate while insulin controls blood glucose levels 1
• Add electrolytes (particularly potassium) to the fluid regimen based on requirements, being careful to avoid insulin-induced hypokalemia 1

Insulin Management Strategy

Continuous IV Insulin Infusion (IVES)

• Use ultra-rapid short-acting insulin analogues administered continuously by electronic syringe 1
• Starting rate typically 0.5-1 unit/hour, adjusted to maintain target glucose 2
• Dilute insulin to a concentration of 1 IU/mL for precise dosing 1

Insulin Dosing Considerations

• Normal weight patients: 0.25-0.40 units per gram of glucose 3
• Obese patients, liver disease, steroid therapy, or sepsis: 0.4-0.8 units per gram glucose 3
• Cardiopulmonary bypass surgery: 0.8-1.2 units per gram glucose 3

Monitoring Requirements

Blood Glucose Monitoring

• Check blood glucose every 1-2 hours during the perioperative period under insulin therapy 1, 2
• Use arterial or venous blood rather than capillary blood, as glucometers overestimate levels especially with vasoconstriction 1
• Consider a capillary reading of 0.7 g/L (3.8 mmol/L) as hypoglycemia requiring immediate correction 1

Electrolyte Monitoring

• Check potassium levels every 4 hours during insulin infusion 1
• Measure serum electrolytes urgently if blood glucose exceeds 300 mg/dL (16.5 mmol/L) to assess for hyperosmolar state 2, 4

Target Blood Glucose Range

• Maintain blood glucose between 5-10 mmol/L (0.9-1.8 g/L or 90-180 mg/dL) 1
• Target blood glucose below 10 mmol/L (1.8 g/L or 180 mg/dL) to avoid hypoglycemia 1
• This range balances infection risk reduction without excessive hypoglycemia 4

Special Considerations

Hyperglycemia Management

• Check for ketosis immediately if blood glucose exceeds 16.5 mmol/L (3 g/L or 300 mg/dL) to rule out ketoacidosis 2, 4, 5
• Measure serum electrolytes urgently to confirm hyperosmolarity (>320 mosmol/L), which requires ICU-level care 2, 4
• Increase insulin infusion rate and ensure adequate hydration with 0.9% normal saline 2, 4

Insulin Pump Users

• Remove personal insulin pumps at the start of the intervention 1
• Immediately initiate IVES insulin therapy as replacement 1

Critical Pitfalls to Avoid

Never Stop Insulin Abruptly

• Do not discontinue IV insulin without overlapping subcutaneous basal insulin, as this causes dangerous rebound hyperglycemia and potential ketoacidosis 2, 4, 5
• When transitioning off IV insulin, give first subcutaneous basal insulin injection 1-2 hours before stopping the infusion 2

Avoid Prolonged Fasting

• Schedule diabetic patients for surgery as early as possible in the morning 1
• Minimize NPO time to reduce metabolic stress 1

Watch for Hyperosmolar State

• Type 2 diabetic patients are at particular risk for hyperosmolar hyperglycemic state, presenting with dehydration and confusion 2, 4
• This requires aggressive fluid resuscitation and ICU management 2

Postoperative Fluid Management

• For most patients, IV fluids are unnecessary beyond the day of operation, except for upper gastrointestinal and pancreatic procedures 1
• Encourage oral intake as soon as the patient is awake and free of nausea 1
• When adequate oral intake is tolerated, discontinue IV fluids 1
• If IV fluids remain necessary, give maintenance fluids at 25-30 mL/kg/day with no more than 70-100 mmol sodium/day, plus potassium supplements up to 1 mmol/kg/day 1