Ad hoc

We set out with a flat basal rate of 0,5 U/h and made adjustments from there. After a few months, we had a basal profile with four different rates in 24 hours that worked quite well.Since then, naturally we have been adjusting the basal profile from time to time. But the ability to adjust the basal profile relatively has been one of the greatest features of the pump. One of the reasons, by the way, that we preferred the Disetronic pump in the first place, because this feature was not common at that time.

For one thing, you can reduce the basal rate to 80 percent for a few hours of sports. Or raise it to 120 percent on a foggy day with lots of reading and watching television and no physical activity. But we have had equally use of the relative basal rate in connection with Emilie’s growth spurts or long periods of hot summer weather.

Growth – and with that the growth hormones that counteracts with insulin – is not linear. Not in Emilie’s case, at least. Emilie sure has weeks and months where she grows more than other weeks or months. And in such a growth phase, we find it very convenient to use the relative basal rate to simply increase the insulin delivery without changing the shape of the basal profile. And then, when Emilie ’stops growing’ – at least for a while – it is easy to return to the standard 100 percent basal rate.

In this matter, also, we have had great use of ‘Pumping Insulin – Everything You Need For Success With An Insulin Pump’ which uses the so-called 500-rule and 100-rule to estimate how much carbohydrate is covered by 1 U of insulin and how many mmol/l the blood glucose can be expected to drop on 1 U.

• According to the 500-rule, 500 divided by your Total Daily Dose of insulin equals how many grams of carbohydrate you can expect 1 U of insulin to cover.

• According to the 100-rule, 100 divided by your Total Daily Dose of insulin equals how many mmol/l you can expect your blood glucose to drop on 1 U of insulin.

We have adapted these rules in a spreadsheet in order to easily tell how Emilie’s insulin sensitivity – with regard to carbohydrates and drop in blood glucose – interacts with the relative basal rate. Here, we also take into account, that by experience, approximately half of Emilie’s Total Daily Dose is basal and the other half is bolus – on average.

So the table shows, that if we increase the relative basal rate, the sensitivity drops and the same amount of bolus insulin covers less carbohydrate or lowers the blood glucose less. Thus, Emilie needs more insulin for her boluses. If we decrease the relative basal rate, the sensitivity increases and the same amount of insulin covers more carbohydrates or lowers the blood glucose more. Now, she needs less insulin for her boluses.

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