Insulin – Continuous Subcutaneous Insulin Infusion (CSII) [‘Insulin Pump’]


Short-acting: Actrapid®, Humulin® S, Insuman® Infusat, Insuman® Rapid, Fiasp® [insulin aspart], NovoRapid® [insulin aspart], Apidra® [insulin glulisine], Humalog® [insulin lispro]


[This monograph covers continuous infusion of insulin – for THREE, FOUR or FIVE daily injections see separate monograph as advice is dependent on the regime used]


  Issues for Surgery

Hypoglycaemia if continued during nil by mouth period.

Increased risk of post-operative infection and delayed wound healing due to poor glycaemic control if discontinued.

  Advice in the Perioperative period

Elective Surgery

The patient’s specialist pump Diabetes Team should be involved in the planning for elective surgery. The patient should bring all necessary pump supplies into hospital with them.

Advice is dependent on the type of surgery and number of meals likely to be missed: -

  • Minor surgery (< 2 hours) / only one missed meal – continue and monitor blood sugars (BMs) hourly at a minimum1, 2, 3; ensure the CSII is sited away from the operation site2.
  • Major surgery (> 2 hours) / more than one meal missed / procedures requiring diathermy – discontinue1, 2, 3. Start variable rate insulin infusion (VRII) immediately2.

It should be assumed that during an elective hospital admission, the patient will take responsibility for the CSII pump during their stay, except for the period of reduced consciousness during surgery when another allocated healthcare professional must take on that obligation.

A concise management plan, detailing the planned continuation/discontinuation of the pump during surgery should be documented in the medical notes; together with signed consent of the patient1.

Emergency Surgery

The specialist Diabetes Team should be contact to review the patients and formulate an individual plan. Continuation of CSII will depend on whether the patient is well enough to manage it on his or her own and the type of procedure/duration of fasting as stated above for Elective Surgery. An assessment of the patient’s blood glucose, blood/urine ketones, + / - venous/arterial pH is advised2.

General Considerations

Current manufacturers guidelines state that CSII pumps must not be exposed to screening radiological procedures (CT, MRI, X-Ray)1, 2. However, this advice is probably based on lack of evidence rather then evidence of harm. US guidance advocates that the pump can remain in place for X-Ray / CT, ensuring that the pump is covered by the lead apron3. Trusts should adopt their own guidelines2.

Where CSII is discontinued for a radiological investigation, it should be immediately reconnected. CSII can be safely suspended / removed for up to an hour at a time without needing alternative insulin2.

Post-operative Advice

Where the pump has been discontinued, the patient’s pump should be restarted as soon as possible post-operatively when they are able to manage it themselves.

Where VRIII has been used, this must be continued for 60 minutes alongside the pump once it has been restarted with hourly BM checks2.

If the patient is unable to manage their CSII post-operatively and they are not nil by mouth (NBM), a basal-bolus regimen is preferable to VRII2. This should be discussed with the specialist Diabetes Team.

  Interaction(s) with Common Anaesthetic Agents

Reduction of Blood-Glucose Lowering Effect

Substances that may reduce the blood-glucose-lowering effect include sympathomimetics (e.g. epinephrine / adrenaline)4.

  Interaction(s) with other Common Medicines used in the Perioperative Period

Enhancement of Blood-Glucose Lowering Effect

Substances that may enhance the blood-glucose lowering effect and increase susceptibility to hypoglycaemia include sulphonamide antibiotics (e.g. co-trimoxazole)4.

Reduction of Blood-Glucose Lowering Effect

Corticosteroids can reduce the blood-glucose-lowering effect of insulin4. Clinically important hyperglycaemia has been seen5. Monitor blood glucose concentrations closely when corticosteroids are given to patients with diabetes5.

Octreotide may increase or decrease insulin requirementsbut most patients with type 1 diabetes are likely to require a reduction in insulin dose6.

  Further Information

Continuous subcutaneous (s/c) insulin infusion (CSII)

This is a continuous s/c infusion of insulin (usually in the form of a rapid-acting insulin or soluble insulin), delivered by a programmable pump. It is designed to mimic physiological insulin delivery over 24 hours with basal and bolus insulin infusions of rapid-acting insulin analogue7. They are currently used by 10-15% of the people with diabetes (mainly type 1)2.

Safe Prescribing of Insulin 

Insulin should be prescribed according to National Patient Safety Agency (NPSA) recommendations for safe use of insulin, with the brand name and units written in full1.



  1. Partridge H, Perkins B, Mathieu S et al. Clinical recommendations in the management of the patient with type 1 diabetes on insulin pump therapy in the perioperative period: a primer for the anaesthetist. British Journal of Anaesthesia 2016; 116(1): 18-26
  2. DTN UK. Clinical Guideline: Guidelines for managing subcutaneous insulin infusion CSII, or ‘insulin pump’ therapy in hospitalised patients. Available at [Accessed 10th August 2019]
  3. Umpierrez GE, Klonoff DC. Diabetes Technology Update: Use of Insulin Pumps and Continuous Glucose Monitoring in the Hospital. Diabetes Care. 2018;41:1579-1589
  4. Summary of Product Characteristics – Actrapid® (human insulin)100 international units/ml, Solution for Injection in a vial. Novo Nordisk Limited. Accessed via 10/08/2019 [date of revision of the text March 2018]
  5. Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. [Accessed on 7th April 2019]
  6. Insulin. In: Brayfield A (Ed), Martindale: The Complete Drug Reference. London: The Royal Pharmaceutical Society of Great Britain. [Accessed 30th March 2019]
  7. Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. [Accessed on 12th March 2019]