With type 1 diabetes, an important distinction for insulins is long-acting versus short or quick-acting. The longer lasting insulins are Lantus, Levemir, Toujeo, Tresibo and a few other new ones. When doing injections, these are the insulins which are known as basal insulins, meaning they keep a baseline level of insulin in the system. When you switch to an insulin pump, all the insulin is replaced with only quick-acting insulin, such as Novolog, Humalog, or Apridra.
In an insulin pump, the basal rate is the hourly drip that takes the place of the long acting insulin. It is what is known as background or baseline insulin. Once this rate is correctly set, the glucose rates (or blood sugars) should not drop or rise when fasting within about 30 mg/dl. If you find that your child is dropping low if he skips or is late for a meal or overnight, the basal rate may be too high. Getting the basal rate right helps with getting the other settings correct.
Different Basal Rates
Many people have several basal rates. They may have a lower rate that runs from midnight til 3 am, then due to dawn phenomen, they may have a slightly higher rate til 6am, then a morning rate and afternoon rate. It’s best to start simple and not overdo with tons of basal rates. From what I’ve seen in practice, the people who do the best have more simple rates.
Basal versus Bolus
The bolus is the amount delivered to cover the food /carbs and the correction dose. Ideally, the percentage of basal versus bolus should be about 50/50. (50% bolus and 50% basal). To determine a starting basal rate from injections, usually the total daily dose is determined and that amount is decreased by 25% because insulin is usually absorbed better from pumps. Then divide the total dose by 2 then by 24 hours for the hourly rate. This can give you a good starting rate. Another way is to look at the child’s weight in pounds times 0.23. The Bode formula is to average the above two together for the starting total dose. Your doctor will determine the beginning settings but this is a guideline so you know what to expect.
Testing Basal Rates
There are several ways to test your basal rates. Usually it is recommended to start with the overnight basal. When your child goes to bed, check the blood sugar, then every 2 hours check it and see whether it remains stable. I usually recommend doing this several days to see if there is a pattern. Having a CGM (continuous glucose monitor) that checks bg every 5 minutes can be extremely helpful for this.
After you have the overnight setting correct, then have your child eat his breakfast later and check bg during that time every 2 hours and see if the blood sugar rises or drops to determine the correct basal for that time of day. Next move on a late lunch, late afternoon, and evening times. This can take a while to determine how the blood sugar does. Always look for a pattern and don’t change settings based on just one number or without speaking with your doctor. Try not to change more than one thing at a time and give it several days to see how the bg responds. A difficult job is for a doctor to look at a pump download when the basal rates or ratios are constantly changed so because you can’t see if a pattern has developed or what change did what. So take it slow and give it time. And remember that sometimes keeping it simple is best.
Need a refresher on treating low blood sugar? Here’s a post on low blood sugars, along with a free printable for your fridge or a caregiver.
For those wanting to learn some indepth pump training info, this is an awesome book! Pumping Insulin