All of the children who receive care at the Yale Program are started on the pump in the office during a one-hour visit scheduled on a Tuesday morning. The child’s total daily insulin dose is calculated and divided in half. One of those halves is further divided by 24, and this becomes the basal rate in units per hour. The other half is divided among the meals and snacks as bolus doses, with the larger proportion being given for breakfast, less for lunch, and more for supper.
After the pump start, the child goes to school as usual. The child or parents are instructed to check blood glucose levels at the usual times (before meals and at bedtime) and, in addition, at 12 AM and 3 AM. They phone in the blood glucose readings the following day and return on Thursday to do the infusion set change on their own with diabetes team members to coach.
During the first few weeks of pump use, the Yale Program social worker is available to discuss any adjustment problems that the child or family might be having. After approximately three to four weeks, the diabetes team (child, parents, and care providers) generally feel quite comfortable with pump treatment, and the initial trials and worries subside.
Nuts and bolts
There are now several insulin pumps on the market as well as a variety of styles of infusion sets and other accessories. (Click here for a list of insulin pump manufacturers.) Here’s how we do it at Yale:
Infusion sets. Children at Yale are instructed to insert the cannula into the upper, outer buttocks. This is the least painful site and has the most subcutaneous tissue. For very young children, Emla cream, a topical anesthetic, may be used. (Emla cream is not sold over the counter; it requires a prescription to purchase.) We don’t recommend this for long-term use, however, since we don’t know what the effects are of using it as frequently as every other day. Ice may also be used to numb the insertion area.
Insulin dosing. Once a person has begun using a pump, his basal rates and bolus doses can be fine-tuned. We have found that most children require a higher basal rate from 9 PM to 3 AM than at any other time of day. The 3 AM basal rate is the lowest. So a typical child on a total daily dose of 12 units would be on basal rate profiles similar to this: 12 AM, 0.3 units/hour; 3 AM, 0.1 units/hour; 7 AM, 0.2 units/hour; 9 PM, 0.4 units/hour. It’s possible that the 9 PM basal rate would need to be increased even further. We feel that this need for more insulin during the night is a result of growth hormone secretion during sleep. Typical bolus doses for this child would be 2.5 units for breakfast, 1.0 units for lunch, 0.5 units for snacks, and 2 units for dinner.
After the initial adjustment to the child’s usual routine, insulin-to-carbohydrate ratios can be investigated with the child, parent, and dietitian. Whatever the insulin-to-carbohydrate ratio is, this is usually the correction bolus to bring blood glucose down 100 mg/dl in the event of high blood glucose. For example, if a child has an insulin-to-carbohydrate ratio of 0.5 units to 15 grams of carbohydrate, 0.5 units of insulin would drop this child’s blood glucose level 100 mg/dl. If the ratio were 1 unit to 15 grams carbohydrate, 1 unit of insulin would usually lower the blood glucose level by 100 mg/dl.
Our rule of thumb for finding a child’s insulin-to-carbohydrate ratio is this: for children under 7 years old, use 0.5 units to 15 grams of carbohydrate. For children 7 to 12 years old, use 0.7 units to 15 grams of carbohydrate. For teens, use 1 unit to 15 grams of carbohydrate. These are just starting points, however. Insulin-to-carbohydrate ratios must be individualized for each child.
School, sports, and vacation
What happens when a child who uses a pump goes to preschool, day care, or primary school? Like any child with diabetes, a child using a pump needs to have an individualized plan of care that is agreed on by parents, teachers, and school administrators. The plan should cover both daily care and emergency care and specify who is responsible for what diabetes-care tasks.