Can a patient with type 1 diabetes (T1D) undergoing a lumpectomy for breast surgery continue to use their Tandem (insulin) pump during the procedure?

Can a Patient with Type 1 Diabetes Keep a Tandem Pump On During a Lumpectomy?

Yes, a patient with type 1 diabetes can and should continue their Tandem insulin pump during a lumpectomy, as this is a minor elective breast surgery where only one meal is missed and the pump site can be positioned away from the surgical field. 1

Decision Framework for Pump Continuation

The British Journal of Anaesthesia guidelines clearly distinguish between procedures where pumps should continue versus those requiring conversion to intravenous insulin. 2 For a lumpectomy specifically:

Factors Supporting Pump Continuation

• Procedure classification: A lumpectomy is a minor elective surgery with short duration (typically 1-2 hours), making it ideal for pump continuation 1
• Fasting duration: Only one meal is missed, which falls within the acceptable window for maintaining continuous subcutaneous insulin infusion 1
• Surgical site: The breast surgical field allows easy positioning of the pump infusion site on the abdomen, thigh, or opposite arm—well away from the operative area 1
• Patient capability: Most pump users are highly motivated and educated about their diabetes management, making them ideal candidates for perioperative pump continuation 2

Preoperative Preparation Requirements

• Re-site the infusion set the day before surgery and monitor blood glucose to confirm proper pump function 1
• Position the cannula away from the breast/chest surgical field—abdomen or thigh are optimal locations 1
• Ensure the patient brings adequate pump supplies (extra infusion sets, insulin cartridges, batteries) for the entire hospital stay 1
• Verify hospital staff are aware the patient is using a pump and have a clear protocol for management 2

Intraoperative Management Protocol

Maintaining the Pump During Surgery

• Continue the usual basal infusion rate throughout the procedure without modification 1
• Monitor capillary blood glucose hourly during surgery—do not rely solely on continuous glucose monitors as they lag during hemodynamic changes 3, 1
• Target blood glucose between 6-10 mmol/L (108-180 mg/dL), with acceptable range of 4-12 mmol/L (72-216 mg/dL) 2
• Protect the pump from the surgical field by securing it to the patient's gown or positioning it on the opposite side of the table 1

Critical Equipment Considerations

• Remove the pump if CT imaging, MRI, or any ionizing radiation/electromagnetic field exposure is planned—these will damage the device 2, 1
• For standard X-rays of the breast, cover the pump with a lead apron if it must remain on the patient 2
• Ultrasound is safe but do not point the transducer directly at the pump 2

When to Convert to IV Insulin Instead

The British Journal of Anaesthesia recommends discontinuing the pump and transitioning to intravenous insulin for: 1

• Major surgery requiring prolonged operative time (>4 hours)
• Abdominal operations where pump site placement is compromised
• Emergency procedures where there is insufficient time for proper assessment
• Any situation where the patient cannot self-manage and staff lack pump expertise 2

If conversion is necessary, start IV insulin infusion at least 30 minutes before disconnecting the pump to prevent rapid hyperglycemia and ketosis 2, 1

Postoperative Management

• Continue hourly glucose monitoring until the patient is fully conscious and capable of managing their pump 1
• The patient should resume their usual pump management as soon as they are alert and able to eat 1
• If the pump was temporarily discontinued, run IV insulin alongside the restarted pump for 2 hours with hourly glucose checks before stopping IV insulin 1

Critical Pitfalls to Avoid

• Never abruptly disconnect the pump without IV insulin backup—type 1 diabetes patients develop hyperglycemia and ketosis within 1-2 hours of insulin deficiency 1
• Do not expose the Tandem pump to MRI, CT, or electromagnetic screening devices as this will permanently damage the electronics 2, 1
• Avoid relying on continuous glucose monitor readings alone during surgery—always confirm with capillary blood glucose due to interstitial lag time 3
• Do not assume all hospital staff understand pump management—confirm a clear protocol exists and the anesthesia team is comfortable with the plan 2

Quality of Life and Outcome Considerations

Continuing pump therapy during minor surgery like lumpectomy maintains superior glycemic control compared to temporary conversion to alternative insulin regimens, with studies showing mean intraoperative blood glucose of 163.5 mg/dL with pump continuation versus 188.3 mg/dL with pump suspension. 4 This approach also preserves patient autonomy and avoids the psychological distress many pump users experience when forced to relinquish their diabetes management. 2