Endocrine Abstracts

Background: Variable rate intravenous insulin infusion (VRIII) or ‘sliding scale’ is required for certain patients with diabetes to keep their blood glucose within the recommended target range during an acute illness or a period of starvation. When used in the right context this has shown to improve outcomes but can also lead to morbidity especially hypoglycaemia.

Aim: Evaluate risk of hypoglycaemia in patients on VRIII with concurrent use of balanced electrolyte solution

Methods: This was an observational study and we included patients who were admitted to medical or surgical wards over a six-week period and who were on a VRIII. Relevant data was collected from patients’ paper notes, observation nursing charts and drug charts. The data was collected for the entire duration patients were on the VRIII. Our hospital has guidelines for the management of patients on VRIII including recommendations on frequency of glucose monitoring and choice of concurrent IV fluids. The recommended balanced solution with carbohydrate substrate used in our hospital is combined 0.18% sodium chloride with 4% glucose (0.18% NaCl+4% glucose). Hypoglycaemia is defined as when the capillary blood glucose falls below 4 mmol/mol.

Results: We included a total of 16 patients in our study with a mean age of 59 years with the majority of patients having type 2 diabetes (87.5%). 0.18% NaCl+4% glucose was used concurrently with the VRIII in 75% of patients. For all the patients that were included in the study a total of 434 hours were spent on a VRIII for which there were 324 capillary blood glucose readings with 3 recorded hypoglycaemia events (<1%) with 2 out of 3 occurring in those who were not on a balanced electrolyte solution.

Discussion: Use of concurrent IV fluids (Normal saline or 5% dextrose) is not a new concept, but often this has been prescribed separately and the infusion switched between the two depending on the threshold levels of capillary glucose levels that has been set by the prescriber. This is prone to human error and consequent adverse events. This study demonstrates that with the concurrent use of balanced electrolyte solution such as 0.18% NaCl+4% glucose, there is a minimal incidence of hypoglycaemia and its concurrent use is recommended to prevent harm to patients on VRIII. This would be of particular importance in general ward or less intensively monitored settings.