The Right Start: age matched algorithms for starting continuous sub-cutaneous insulin infusion therapy (CSII)
Introduction: At the start of insulin pump therapy usually only a single basal rate, one insulin correction factor and one carbohydrate ratio are prescribed. Not only does this approach fail to match normal physiology but experience gained over 5 years of providing an insulin pump service found that these settings invariably needed early and frequent adjustment. As a result algorithms were developed to give a more precise pattern of basal rates and correction factors.
Methods: A spreadsheet was developed into which was fed the current total daily insulin dose before starting CSII. This figure was used to calculate a 25% reduction in total insulin dose together with 5 different basal settings, four insulin sensitivity settings for blood glucose correction and four carbohydrate sensitivities for mealtime bolus calculation. These results were transferred to a document template which acted as a printed record of initial pump settings.
Results: The algorithms have been used for over 80 pump starts to date. Using the algorithms has led to a reduction in the number and frequency of adjustments being required in the first weeks after starting CSII. There was also a noticeable reduction in the frequency of nocturnal hypoglycaemia. However one algorithm was not suitable for all ages, with younger children requiring a smaller reduction of total insulin but higher evening basal rates, and young adults needing two night time basal settings.
Outcomes: By reducing the number of early adjustments needed there has been a marked reduction in the workload associated with starting on an insulin pump. The spreadsheets and linked document files have been made freely available and used by other clinics for calculating initial pump settings for children and adults.