Insulin Pumps and Sensors

1. Insulin Pumps and Sensors Eric L. Johnson, M.D. Assistant Medical Director Altru Diabetes Center Assistant Professor Department of Family and Community Medicine University of North Dakota School of Medicine and Health Sciences

2. Objectives • Discuss basic operations of pumps and sensors • Discuss suitable patient types for pump and/or sensor use • Discuss insulin kinetics in the context of pump and sensor use • Discuss advanced operations of pump and sensor devices

3. 3 Factors for Glycemic Control with a Pump • A1C • current standard for diabetes control (ADA, AACE) • Standard Deviation • Measure of GlycemicVariability (Range) • % of time <70 mg/dl - too many lows>>lower A1C Medtronic

4. Continuous Subcutaneous Insulin Infusion (CSII)‘Insulin Pumps’ • Technology origins 1960’s, really advanced in the last decade • Deliver insulin continuously (‘basal’) and for food (‘bolus’) • Current technology still requires significant user interface • DON’T hook up, turn on and forget about them

5. Continuous Glucose Monitoring(Sensors) • Technology developed over the last decade, clinic use first, now also home use • Record glucose 24/7, usually displayed every 5 minutes • Record interstitial fluid glucose, not serum or capillary, generally ~15 min ‘lag’

6. Pumps and Sensors • Interfaced devices developed last 3 to 4 years • Still not “closed loop” • Patient gets info, has to act on it • Many have high/low alarms, trends alarm (rapid rise or decline)

7. What Do Pumps Not Do? • Take over care of patient’s diabetes • Make diabetes perfect • Lessen the “workload” of diabetes (it’s just different) • Still need to do the basics…….

8. What Do Pumps Do? • Mechanically deliver insulin to the subcutaneous tissue through plastic tubing and/or small plastic or metal catheter • Small ‘computers’ in the pump assist the user in delivering proper basal and bolus insulin dosing

9. What Do Pumps Do? • Only rapid acting insulin is used • Some is delivered continuously units/hour (like an insulin drip) (‘basal’) • Some is delivered ‘bolus’ with food • Insulin is absorbed more consistently

10. What Do Pumps Do? • Different basal rates at different times of day (good to match activity) • Bolus insulin all at once or deliver over a specified time period • Potentially less variability and lower A1C • More recent data strongly supports pump/sensor use (STAR 3 trial, others) JDRF NEJM Oct 2008 STAR 3 trial N Engl J Med. 2010 Jul 22 French Study Journal of Pediatrics 2010

11. Normal Insulin Production:The Pancreas A healthy pancreas releases insulin automatically, on average, every ten to 14 minutes1, in amounts appropriate for varying blood glucose levels. Bolus dose • Normal Insulin Secretion Insulin Basal dose 0 hr 12 hrs 24 hrs Adapted from 1. Marchetti, P, et al. Diabetes, Vol 43, p. 827-839, June 1994. Schematic representation only

12. Basal / Bolus TherapyInsulin Pump Bolus Insulin Insulin Needs Basal Insulin -Variable basals (not fixed) -Bolus-Immediate, Square, Dual Wave Time of Day

13. Continuous Glucose Monitoring Systems(CGMS) (Sensors)

14. What Do CGMS (Sensors) Not Do? • Completely eliminate the need for fingerstick blood glucose testing (although it’s a lot less) • ‘Take over’ diabetes control • Give 100% data all of the time

15. What Do CGMS (Sensors) Do? • Potential for less variable blood glucose JDRF study, NEJM 2008 STAR 3 NEJM 2010 • Potential for less apprehension at work, at school, while sleeping, or driving • Give good data a majority of the time • Glucose value every 5 minutes • High/low alarms

16. Patient Selection for Sensors/Pumps

17. Patient Selection • Mature, accepting of diabetes • Psychologically stable • Good with technology- Can text a photo on a cell phone? • Younger patients don’t think of these as exotic electronic devices • Don’t let technology bias influence negatively

18. Patient Selection • Compulsive enough to do fingerstick glucose 4 times or more daily • Will not need as many fingersticks with sensor, but it requires frequent attention • Generally will not ‘motivate’ nonadherent patient

19. Patient Selection • Patients who are not meeting goals on multiple daily injections • Usually patients who are good with followup (phone/in person/e-mail/appointments) • Patients with a lot of variability • Patients with asymptomatic hypoglycemia • Usually start pump first, add sensor later (2 to 4 weeks)

20. Patient Selection • Selecting proper patients is important to maximize success • Proper training and followup are critical for success

21. Pumps and Sensors

22. Animas

23. Omnipod pump with remote Not shown- “patch pumps” Investigational Navigator CGMS

24. Medtronic Minimed

25. White Board Concepts • Use your brain as a pancreas • Different Basals, Different Boluses • What does insulin really do? Myths What?!?! It’s not instant?!? • Successful bolusing: hit the receiver down the field! • What are square and dual wave boluses? • What is standard deviation?

26. CGMS Data

27. Pregnant patient on pump + sensor

28. Note +/- BG Note % basal vs. % bolus

29. Fingersticks and Boluses

30. Average is high ~200, lots of variability

31. Note large number of correction boluses

32. +/- BG AUC

33. Tips for More Successful Pump Use • Pump infusion sites can degrade with high level, vigorous exercise • Protect from heat/sun/cold  • Change insulin infusion sites every 2 ½ to 3 days.  No exceptions

34. Tips for More Successful Pump Use • Advanced features. Use Them! Alarms, dual wave bolus, variable basals • Elevated Blood Sugar, no response from correction bolus- take a shot, change out

35. Tips for More Successful Sensor Use • Calibrations are MUCH better if done during a time of blood sugar stability • If calibrations are done when blood sugars are changing relatively rapidly, you may actually be amplifying error • Wash hands/avoid hand sanitizer for best fingerstick results 

36. Tips for More Successful Sensor Use • Ideal fingersticks have a +/- of up to 15%    • Ideal sensors have a +/- of about 15% • It's unlikely that they will match exactly • Fingerstick blood sugars at values >280 or <80 aren't as good for calibrating

37. Tips for More Successful Sensor Use • Sensors are typically 15 or 20 minutes behind • Transmitter may need charging if values/data are poor quality

38. Tips for More Successful Sensor Use • Initially, low alarms should be no lower than 80, and high alarms should be 220-240 • Patients have a lot more glucose variability than they think (“my control is terrible on this thing”)

39. Tips for More Successful Sensor Use • If patients tell you their alarms are going off all the time, • It's usually not the pump and sensor that are the problem- their insulin/activity/food are what need to be changed

40. Summary • Insulin pumps are excellent tools for diabetes management • Sensors are excellent tools for diabetes management • Still need to do basic diabetes cares • Choose patients selectively for best results • Training and followup are critical for success

41. Contact Info/Slide Decks/Media e-mail eric.l.johnson@med.und.edu ejohnson@altru.org Phone 701-739-0877 cell Slide Decks (Diabetes, Tobacco, other)http://www.med.und.edu/familymedicine/slidedecks.html iTunes Podcasts (Diabetes)http://www.med.und.edu/podcasts/ or iTunes>>search UND Medcast (1/21/10 release) WebMD Page:http://www.webmd.com/eric-l-johnson Diabetes e-columns (archived): http://www.ndhealth.gov/diabetescoalition/DrJohnson/DrJohnson.htm