Brands of insulin used in CSII
Actrapid®, Apidra®, Fiasp®, Humalog®, Humulin® S, Insuman® Infusat, Insuman® Rapid, Lyumjev®, NovoRapid®
Issues for surgery
Hypoglycaemia if continued during nil by mouth period.
Risk of diabetic ketoacidosis (DKA) if usual regime discontinued and switched to alternative insulin regime but also risk of DKA if CSII continued perioperatively and pump failure occurs (see Further information).
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.
- If the patient reports that they usually get capillary blood glucose (CBG) less than 6mmol/L in the morning, advise them to reduce their basal insulin to 80% of their normal rate on the night before their surgery.
- If the patient reports that they usually get CBG less than 6mmol/L during the day, advise them to reduce their basal insulin to 80% of their normal rate on awakening on day of surgery.
Advice on continuation of CSII in the perioperative period is dependent on the type of surgery and number of meals likely to be missed:
Minor surgery (less than 2 hours) / only one missed meal
Continue (see Further information):
- Monitor CBG hourly at a minimum on day of surgery and aim to keep between 6 and 10mmol/L. If patient usually uses another method of monitoring glucose see Further information
- Ensure the cannula and pump is sited away from the operation site (not between the diathermy plate and diathermy if this will be used during surgery– see Further information).
- Ensure the cannula and the pump can be easily observed and is accessible to the theatre team during the procedure (upper arm is usually a good site for abdominal and lower limb surgery and thigh is usually a good site for head, neck and upper limb surgery)
- Ensure use of a Teflon® cannula set
- Ensure patient is aware to bring all necessary pump supplies into hospital with them.
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 patient.
Major surgery (more than 2 hours) / more than one meal missed
Continue until day of admission and follow advice as above.
Discontinue on admission and start variable rate intravenous insulin infusion (VRIII) immediately. If pump is removed, ensure that it is stored safely.
For procedures requiring diathermy or radiological procedures – see Further information.
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 ketones, + / - venous / arterial pH is advised.
Perioperative considerations (if CSII continued)
Check correct connection and functioning of pump.
Check CBG every 30 - 60 minutes to ensure in target range of 6 - 10mmol/L.
If CBG rises above 12 mmol/L, consider pump failure; check blood ketones, commence VRIII and remove pump cannula.
Post-operative advice
If continued
Move cannula to usual position and check patient satisfied with pump function and glucose control. Advise patient to check CBG more regularly for few days post-operatively.
If discontinued
Where the pump has been discontinued, it should be restarted as soon as possible post-operatively when they are able to manage it themselves.
Where CSII is discontinued for a radiological procedure, it should be immediately reconnected. CSII can be safely suspended / removed for up to 30 minutes at a time without needing alternative insulin.
Where VRIII has been used, this must be continued for 60 minutes alongside the pump once it has been restarted with hourly CBG checks. Advise patient to check CBG more regularly for few days post-operatively.
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 VRIII. This should be discussed with the specialist diabetes team.
Interactions 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).
Interactions 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).
Reduction of blood-glucose lowering effect
Corticosteroids can reduce the blood-glucose-lowering effect of insulin. Clinically important hyperglycaemia has been seen. Monitor blood glucose concentrations closely when corticosteroids are given to patients with diabetes.
Somatostatin analogues (octreotide and possibly lanreotide) may increase or decrease insulin requirements, but most patients with type 1 diabetes are likely to require a reduction in insulin dose, with some studies suggesting a potential reduction of 50% in patients taking concomitant octreotide. Monitor CBG when somatostatin analogues are given to patients with diabetes.
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 analogue. They are currently used by approximately 15% of people with type 1 diabetes mellitus.
Risk of diabetic ketoacidosis (DKA)
As there is no long-acting insulin component in CSII, fasted patients are at risk of DKA in case of failure, disconnection or occlusion of the pump. While the patient is sedated/anaesthetised this risk can be mitigated by regular CBG monitoring and intravenous access. If CBG greater than 12mmol/L check blood ketones, remove cannula and commence VRIII immediately.
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 full.
Safe continuation of CSII
The Centre for Perioperative Care (CPOC) has developed comprehensive guidance to support Trusts in facilitating the continued use of CSII in patients who meet agreed criteria, have been fully informed of the risks and alternatives available and wish to continue their CSII. Health Boards / Trusts should ensure that they have pathways in place to allow patients to continue to use their CSII when the anticipated fasting period is only one missed meal.
Procedures requiring diathermy/radiological procedures
The manufacturers of insulin pumps advise that CSII should not be continued in the presence of diathermy, but this is based on perceived rather than actual risk.
Furthermore, current manufacturers guidelines state that CSII pumps must not be exposed to screening radiological procedures (CT, MRI, X-Ray). However, this advice is probably based on lack of evidence rather than 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 apron.
Monitoring
All patients with CSII should have CBG monitoring on day of surgery. If patient usually uses continuous glucose monitors (CGM) this assesses subcutaneous interstitial glucose concentrations which lag behind CBG by approximately 15 minutes and so is not suitable for sole use in sedated / anaesthetised surgical patients.
References
Baxter K, Preston CL (eds), Stockley’s Drug Interactions (online) London: Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 1st March 2021]
Centre for Perioperative Care. Guideline for Perioperative Care for People with Diabetes Mellitus Undergoing Elective and Emergency Surgery (March 2021). Available at: https://cpoc.org.uk/guidelines-resources/guidelines [Accessed on 8th March 2021]
DTN UK. Clinical Guideline: Guidelines for managing subcutaneous insulin infusion CSII, or ‘insulin pump’ therapy in hospitalised patients. Available at www.abcd.care [Accessed 10th August 2019]
Insulin. In: Brayfield A (Ed), Martindale: The Complete Drug Reference. London: The Royal Pharmaceutical Society of Great Britain. http://www.medicinescomplete.com [Accessed 1st March 2021]
Joint Formulary Committee. British National Formulary (online) London: BMJ Group and Pharmaceutical Press. http://www.medicinescomplete.com [Accessed on 1st March 2021]
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
Summary of Product Characteristics – Actrapid® (human insulin) 100 international units/ml, Solution for Injection in a vial. Novo Nordisk Limited. Accessed via www.medicines.org.uk 01/03/2021 [date of revision of the text October 2020]
Umpierrez GE, Klonoff DC. Diabetes Technology Update: Use of Insulin Pumps and Continuous Glucose Monitoring in the Hospital. Diabetes Care. 2018;41:1579-1589