July 19, 2007
Hyperglycemia and DKA, Insulin Pumps
Question from Danbury, Connecticut, USA:
My son has been pumping for about five weeks. In the last week, he has experienced many lows, which have required me to suspend his basal rate. This happens between midnight and 6 a.m. and in between breakfast and lunch. My doctor does not want his insulin suspended for more than three hours, citing that although his beta cells may be producing insulin, this production is unpredictable and may not happen every day the same way. Their opinion is that if he does not have at least a pulse of insulin every two to three hours, he is at risk of producing ketones even with blood sugar numbers within his acceptable range of 70 mg/dl [3.9 mmol/L] to 140 mg/dl [7.8 mmol/L].
His blood glucose readings have had the following pattern: pre-bed (8 p/m.) 90 mg/dl [5.0 mmol/L] to 110 mg/dl [6.1 mmol/L], with a rise from 10 p.m. to midnight to 150 mg/dl [8.3 mmol/L] to 175 mg/dl [9.7 mmol/L]. By 3 a.m., with his basal suspended at 11 p.m. and 0.05 from 8p.m. to 11 p.m., he is 80 mg/dl [4.4 mmol/L] to 100 mg/dl [5.6 mmol/L] and remains that way with no basal until about 5 a.m. If not for the overnight drop, I would increase his early evening basal to avoid the 10 p.m. to midnight rise, but I worry that if he weren’t that high, he would go too low by 3 a.m.
The only way to give him even the slightest insulin overnight as my doctor wishes would be to feed him with the insulin to ensure he does not go low. This seems completely backwards to me. So, I am looking for a second opinion. If his body is bringing him to an acceptable number naturally, can his insulin be suspended for about seven hours overnight without risk of “spilling ketones,” if we continue to perform midnight and 3 a.m. blood glucose checks and check for ketones when he wakes up each day? I was told that trace or small ketones is acceptable, but anything beyond that is cause for concern.
For the daytime, I make sure he has a snack and a bolus between breakfast and lunch when he has no basal, so that there is no more than 2.5 hours between boluses. This is much easier to manage when he is awake.
Answer:
It seems that your child is having a strong “honeymoon” phase right now with his diabetes and, therefore, needs very little basal insulin. This very low insulin requirement can be an issue with very young children started on insulin pumps very early in the course of the disease. I am less concerned that he will have ketones by the morning (since he’s probably making some of his own insulin) than that the infusion set may not work well if you need to suspend for so long so often.
Some centers have recommended using diluted insulin in these young children. I have found that doing every other hour basals (one hour 0.05, one hour off, one hour back on) works reasonably well, although at our center we haven’t started very young children who’ve had diabetes less than one year on pumps because of concerns about running into very low insulin requirements. In the morning, you may just need to decrease his carbohydrate to insulin ratio again so that you can have some basal running. In our experience, most very young children (all out of honeymoon in our study) need much lower basal rates (adjusted for body weight) than older kids between midnight and 6 a.m. During the daytime, the basal rates are more similar.
LAD
