March 20, 2005
Exercise and Sports, Insulin Pumps
Question from Nottingham, New Hampshire, USA:
I use the MiniMed 512 insulin pump with silhouette infusion sets. I am a 56 year old active sports enthusiast who has type 1 diabetes. I am outdoors, including temperatures well below freezing, for very long periods of time all year long, such as for snowshoeing, cross country skiing, and camping in the winter time. My problem is air bubbles in the tubing. I use only about 15 units of Humalog per day in the pump. I actually overheat with the strenuous exercise while wearing the pump in a waist pouch (the pouch becomes warm and sweaty). While snowshoeing or cross country skiing, I can go back and forth from VERY warm to VERY cold in the severe New England mountain temperatures in a matter of minutes. I suspect this is the reason for the air bubbles. There is no way to avoid this while doing these activities. The reservoir is loaded with insulin at room temperature and I have no problem with air in the reservoir when filling it. The air bubble problem does not occur in warmer outdoor conditions, well above freezing. I cannot expose the pump to the cold by wearing it on a waist clip. Often, I only have a shirt and/or a light vest on while being active, then put on down clothing and Gore-Tex when stopping. There would also appear to be a problem if I expose the tubing to the cold while I have to look for air bubbles. What do you recommend?
Answer:
I cannot claim to have experience with your particular issue, although I am also a New Englander and wear a pump myself. Have you discussed this issue with Medtronic? They may have some valid suggestions for you based on the experience of other pump users. Have you tried NovoLog in your pump? NovoLog may produce fewer air bubbles than you are currently experiencing with Humalog. Remember that a change in insulin will require physician supervision.
You may also wish to connect with other extreme winter athletes via the Diabetes Exercise and Sports Association.
DMW
