Variable Rate Intravenous Insulin Infusion

The Variable Rate Intravenous Insulin Infusion (VRIII) guideline was rolled out across NHSGGC in March 2019 and replaces all guidance relating to 'insulin sliding scales'. The guideline should be used in:

• surgical patients with diabetes undergoing operations e.g. fasting >24 hours, emergency surgery and poor glycaemic control.
• medical patients with diabetes who have uncontrolled hyperglycaemia or who are unable to eat and drink due to prolonged fasting, nausea, vomiting or reduced consciousness.

The guideline should not be used in patients with:

• Diabetic ketoacidosis
• Hyperglycaemic hyperosmolar state / hyperosmolar non-ketotic coma
• pregnant patients requiring intravenous insulin; there is a separate guideline for maternity which is in the process of being rolled out.

For advice on when to use a VRIII and what to do with the usual insulin, and how to stop a VRIII please the following links:

• When to use a VRIII and what to do with the usual insulin?
• How to stop a VRIII?

The VRIII guideline and supporting material e.g. FAQ document, implementation memo, designated stock locations of VRIII IV fluids, is available:

• on the NHSGGC Clinical Guidelines Platform.
• on NHSGGC StaffNet / Clinical Info / Medicines Prescription Charts (homepage) (link is only active if accessing via NHS network).

The NHSGGC VRIII for adults training video (9 minutes) here. 

Guideline reviewed: June 2022

Page updated: November 2025