Defining optimal glucose targets in critically ill patients with pre-existing type 2 diabetes and chronic hyperglycaemia.

The intervention is a change in insulin protocol in the Intensive Care Unit (ICU) patients with chronic hyperglycaemia or poorly controlled pre-existing type 2 diabetes. Patients will be identified by a Hba1c test (glycated haemoglobin) on admission to ICU. Patients with a HbA1c >6.9% (or 51 mmol/mol) will be treated with a new Insulin protocol. This study will be performed sequentially; initially (6 months) the study will observe the current Insulin regimen, followed by a 2nd 6 month period in which the intervention (an altered Insulin regimen) will be implemented. The 2 study periods will be separated by 1 month to prevent patients from the control period being included in the intervention period. The new protocol targets blood glucose levels of 10-14 mmol/L in chronic hyperglycaemic patients and poorly controlled type 2 diabetic patients. The current insulin protocol targets blood glucose levels of 6-10 mmol/L. This will involve a change in practice for the bedside nurse who will administer insulin as required to reach the target blood glucose level. The new protocol will result in the administration of less insulin than the current protocol. All patients (including diabetic patients) with a HbA1c of 6.9% or below will continue with the control Insulin regimen if required.