Insulin Pump Therapy in Diabetes Management

Introduction to Insulin Pump Therapy

• The insulin pump is a small, programmable, battery-operated device that administers rapid-acting insulin continuously, mimicking physiological insulin release over 24 hours through basal infusions and boluses, allowing for better glycemic control and greater flexibility for patients with diabetes, as recommended by the British Journal of Anaesthesia 1, 2

Components and Basic Functioning

• The insulin pump uses only rapid-acting insulin (e.g., Novorapid, Humalog, Apidra) administered subcutaneously 2
• Patients use a disposable subcutaneous metal or plastic cannula changed every 2-3 days, connected to the pump via a flexible tube 3
• There are also "patch pumps" without tubes that adhere to the skin and are controlled manually 3

Insulin Administration

Basal Insulin

• Basal insulin is the constant programmed infusion to maintain euglycemia during fasting and prevent ketosis, with the basal rate adapted individually based on factors like insulin sensitivity and the dawn phenomenon, as suggested by the British Journal of Anaesthesia 2
• The hourly infusion rate is typically around 50% of the total daily insulin requirement 2

Bolus Insulin

• Bolus insulin is administered before or during meals to control glycemia during carbohydrate absorption, calculated based on the amount of carbohydrates ingested and the patient's insulin-to-carbohydrate ratio, as recommended by the British Journal of Anaesthesia 2, 3

Advantages of Insulin Pump Therapy

• Precise quantitative administration of basal insulin with the ability for instant change or suspension 1
• Accurate bolus calculation for meals using integrated calculators 2
• Greater flexibility to adapt to different situations (e.g., exercise, stress, menstrual cycle) 3
• Better fasting glycemic control due to stable insulin administration 2

Important Considerations

• Disconnection, occlusion, or interruption of the pump can cause insulin deficiency within 1 hour and absolute deficiency within 4 hours, risking hyperglycemia and ketosis, as warned by the British Journal of Anaesthesia 4
• Regular glucose monitoring is essential, especially when changing settings or in special situations, as emphasized by the British Journal of Anaesthesia 5
• Acceptable blood glucose levels are between 4 and 12 mmol/L, with a target range of 6-10 mmol/L, as suggested by the British Journal of Anaesthesia 5

Special Situations

Hypoglycemia

• If glucose levels fall below 4 mmol/L, treat according to protocol with IV glucose if necessary, as recommended by the British Journal of Anaesthesia 6
• Modern pumps can suspend insulin administration when glucose is low or predicted to drop within the next 30 minutes, as noted by Diabetes Care 7

Hyperglycemia

• If glucose levels exceed 14 mmol/L, check the pump and infusion set, and perform a ketone test, as advised by the British Journal of Anaesthesia 6
• Contact a diabetes specialist if ketones are present 6

Hospitalization

• If the patient is fasting or requires IV insulin, start IV insulin at least 30 minutes before removing the pump, and infuse initially at the basal rate per hour, adjusting according to glucose levels, as recommended by the British Journal of Anaesthesia 6
• When returning to the pump, connect it and maintain the basal rate for at least 2 hours before suspending IV infusion 6

Surgery and Procedures

• For minor surgeries, insulin pump therapy can be continued with prior agreement and shared care between the patient and healthcare professionals, as suggested by the British Journal of Anaesthesia 1
• For major or emergency surgeries, pump therapy is not appropriate and should be suspended, resorting to IV insulin according to local protocol, as recommended by the British Journal of Anaesthesia 6
• The pump should be removed during radiological procedures like CT/MRI or body X-rays, as advised by the British Journal of Anaesthesia 5

Insulin Pump Meal Announcement and Bolus Management

Requirement to Announce Meals

Bolus Calculation Mechanics

Importance of Meal Announcement

Timing of Bolus Delivery

Adjustments for High‑Fat or High‑Protein Meals

Common Pitfalls and Errors

Evidence level: expert consensus/guideline recommendation (British Journal of Anaesthesia, 2016).