Presentation is loading. Please wait.

Presentation is loading. Please wait.

July 2009 Darrell M. Wilson, MD (Stanford)Slide 1Submission Doc: 15-09-0537-00-0006 July 2009 Slide 1 Project: IEEE P802.15 Working Group for Wireless.

Similar presentations


Presentation on theme: "July 2009 Darrell M. Wilson, MD (Stanford)Slide 1Submission Doc: 15-09-0537-00-0006 July 2009 Slide 1 Project: IEEE P802.15 Working Group for Wireless."— Presentation transcript:

1 July 2009 Darrell M. Wilson, MD (Stanford)Slide 1Submission Doc: July 2009 Slide 1 Project: IEEE P Working Group for Wireless Personal Area Networks (WPANs) Submission Title: BAN and Diabetes a template for medical device communication Date Submitted: May 14, 2009 Source: Darrell M. Wilson, MD Contact: Stanford Voice: , Re: Diabetes Abstract:. Purpose: Same Notice:This document has been prepared to assist the IEEE P It is offered as a basis for discussion and is not binding on the contributing individual(s) or organization(s). The material in this document is subject to change in form and content after further study. The contributor(s) reserve(s) the right to add, amend or withdraw material contained herein. Release:The contributor acknowledges and accepts that this contribution becomes the property of IEEE and maybe made publicly available by P

2 July 2009 Darrell M. Wilson, MD (Stanford) Slide 2 IEEE Body Area Network Diabetes - July 09 Darrell M. Wilson, MD dped.stanford.edu

3 July 2009 Darrell M. Wilson, MD (Stanford)Slide 3Submission Doc: Goals Review diabetes for a few minutes Discuss current conventional treatment approaches Discuss cut-edge approaches include closed loop systems and there problems

4 July 2009 Darrell M. Wilson, MD (Stanford)Slide 4Submission Doc: Goals What we envision as Body Area Network upsides for diabetes What we envision as important features/functional aspects to such a network Q and A

5 Diabetes Mellitus Major Forms Insulin dependent IDDM Juvenile onset Brittle Type 1 Non-insulin dependent NIDDM Adult onset Type 2 Atypical Diabetes Minor forms

6 Genetics Environmental triggers Insulitis Type 1 Diabetes Diabetes Exposure Renal Complications Eye Complications Large Vessels

7 Honeymoon

8 Travis, DM in Children, MPCP#29, 1987 Diab Care 29:1150, 2006

9 July 2009 Darrell M. Wilson, MD (Stanford)Slide 9Submission Doc: Diabetes Impact Type 1 ~ 800,000 to 1,000,000 –~120,000 < 20 years of age Type 2 ~ 7 million –another ~ 7 million undiagnosed –Prevalence 1.3% years of age 6.2% years of age 10.4% years of age

10 Diabetes Care 26: , 2003 Costs Continue to Increase (U.S.) (in Billions of Dollars)

11 Mazze DTT 2008 Single Subject without DM

12 Mazze DTT 2008 Single Subject With DM

13 Hemoglobin A1c

14 Hemoglobin A1c

15

16 DCCT DCCT NEJM, 329:977,1993

17 Glucose Control Glycosylated Hemoglobin DCCT NEJM, 329:977,1993

18 Retinopathy Primary Prevention DCCT NEJM, 329:977,1993

19

20 Insulin Action Curves

21 Four Shots

22 July 2009 Darrell M. Wilson, MD (Stanford)Slide 22Submission Doc: Pumps What do they do? Basal(s) rates Meal boluses Correction bolus What don't they do? Still open loop Require a great deal of attention to detail

23 Pumps

24 Pump Example

25 July 2009 Darrell M. Wilson, MD (Stanford)Slide 25Submission Doc: How to Select the Correct Amount of Insulin Good carbohydrate counting –Frequently in error Using pumps –Use the calculators/wizards Using injections –Use a discrete plan Adjusting for exercise Bedtime snacks

26 July 2009 Darrell M. Wilson, MD (Stanford)Slide 26Submission Doc: Pumps and Injections I like dose calculators –Earlier age of dosing competency –The paradox of both greater dose flexibility and consistency Time of day Fine tuning –Better download and data analysis Meal buckets –Future automatic adjustment of parameters –Lead into the feedback controlled pump

27 July 2009 Darrell M. Wilson, MD (Stanford)Slide 27Submission Doc: Measurement of Glucose Direct –Methods meters future sensors –Data analysis average variability extremes

28

29 Insulin Variability Heinemann DTT 4:673, 2002

30 July 2009 Darrell M. Wilson, MD (Stanford)Slide 30Submission Doc: Maximizing Bolus Delivery Getting the Bolus The price of a missed bolus is high Burdick Peds 113:211e, 2004

31 July 2009 Darrell M. Wilson, MD (Stanford)Slide 31Submission Doc: Kinetics vs Dynamics

32 Snacks LOW FAT 30 gm CHO 2.5 gm protein 1.3 gm fat 138 kCal HIGH FAT 30 gm CHO 2 gm protein 20 gm fat 320 kCal

33 July 2009 Darrell M. Wilson, MD (Stanford)Slide 33Submission Doc: Sensor Lag

34 Feature Summary Paradigm 722 DexCom 7-plus Navigator Rate of change arrows Yes Projected low alarm No Yes Days of wear53-75 Ability to downloadYes Ability to integrate with pump Yes (MiniMed) NoPending (Cozmo)

35 >2 (mg/dL)/min < -2 (mg/dL)/min -1 to -2 (mg/dL)/min 1 to 2 (mg/dL)/min -1 to 1 (mg/dL)/min Trend Arrows NavigatorMiniMed Updated every minute Updated every 5 minutes

36 July 2009 Darrell M. Wilson, MD (Stanford)Slide 36Submission Doc: FreeStyle Navigator Continuous Glucose Monitor Receiver Transmitter Sensor/Sensor Mount

37 FreeStyle Navigator System Intended Features –Home continuous monitoring system. –3-day sensor continuously measures glucose –Transmitter sends updated glucose reading every minute –Alarms for hi/lo glucose –Alarms for projected hi/lo glucose –On-board trend and statistical reporting –Event entry (food, insulin, meds, exercise, etc) –60-day memory & upload to computer –Traditional glucose meter built in System calibration Backup glucose meter

38 Pilot Study to Evaluate the Navigator in Children with T1D 30 children with T1D HA1c 7.1 ± 0.6% Smart pumps Ask to wear sensor daily Algorithm based adjustments of insulin infusion rates

39 MiniMed Paradigm REAL- Time Insulin Pump and Continuous Glucose Monitoring System

40 DexCom 7 Plus 91 insulin requiring adults –75 Type 1 –16 Type 2 Three 72 hour wears Randomized –Blinded –Shows 2/3 wears Garg Diabetes Care 29:44–50, 2006

41 July 2009 Darrell M. Wilson, MD (Stanford)Slide 41Submission Doc: Modes of Glucose Sensor Use Meter replacement Hypoglycemia alarm –Down alert Hyperglycemia alarm –Up alert Pattern recognition Dynamic adjustment Infusion controller –Suggestive vs closed loop Nocturnal pump shutoff for unaddressed low alarms –Non-diabetic inpatients –Research studies

42 0 – 6 mos. 6 – 12 mos. 0-6 Months of the Study

43 Changes in A1c in > 25 yr olds Difference: -0.53% + P-value <0.001

44 Differences in Distribution of A1c Levels in > 25 yr olds at 26 Weeks Cumulative % 26 week glycated hemoglobin (%)

45 Changes in A1c in 8-14 yr olds P-value=0.29

46 P=0.04 P=0.009 P= 0.01 Secondary A1c Outcomes in 8-14 yr olds

47 Changes in A1c in yr olds P-value=0.52

48

49 Artificial Pancreas ( -cell) Artificial Pancreas Software (APS) Features: –Communication with sensors & pumps –Modularity, Plug-and-Play (PnP) –Human Machine Interfaces (HMIs) –Physician control –Data storage –Audio & Visual alarms –Standalone application –Data recording –Safety and redundancy

50 July 2009 Darrell M. Wilson, MD (Stanford)Slide 50Submission Doc: B. Wayne Bequette Proportional-Integral-Derivative (PID) Control Manipulated Input (insulin) Error = setpoint – measured output = desired glucose – measured glucose Proportional gain Integral timeDerivative time Integral windup can lead to postprandial hypoglycemia Many possible tuning procedures

51 B. Wayne Bequette Internal Model Control (IMC) Controller (approximate model inverse) sensor pump subject glucose setpoint Insulin- Glucose Model Sensor Model ~ y model- predicted output measured output (glucose) y + _ manipulated input (insulin infusion) u r Estimates of other variables (possible) model-reality mismatch

52 July 2009 Darrell M. Wilson, MD (Stanford)Slide 52Submission Doc: B. Wayne Bequette Controller Information Feedback-only Meal Announcement (feedforward) Meal Detection –Meal size estimation vs. priming bolus Insulin-on-Board –Impose infusion constraint vs. modified tuning Individualization –Subject supplied history vs. results of protocol

53 July 2009 Darrell M. Wilson, MD (Stanford)Slide 53Submission Doc: Closed-loop vs. hybrid control MeanNocturnalPeak PP Full CL156 ( )109 (87-131)232 ( ) Hybrid135 ( )114 (98-131)191 ( )

54 July 2009 Darrell M. Wilson, MD (Stanford)Slide 54Submission Doc: What we would like to see in a Body Area Network A stable, company neutral system to reliably exchange data among diabetes related devices –Glucose meters –Glucose sensors –Insulin infusion devices –Control algorithm devices (if not embedded)

55 July 2009 Darrell M. Wilson, MD (Stanford)Slide 55Submission Doc: What we would like to see in a Body Area Network A stable, company neutral system to reliably exchange data among diabetes related devices –External alarms –Activity monitors –GPS –Phone –External communication devices –Ear buds?

56 July 2009 Darrell M. Wilson, MD (Stanford)Slide 56Submission Doc: What we would like to see in a Body Area Network Note the difference – NOT just a sensor network –Insulin infusion devices –Insulin infusion algorithm NOW we are infusing insulin, a potential lethal medicine

57 July 2009 Darrell M. Wilson, MD (Stanford)Slide 57Submission Doc: What we would like to see in a Body Area Network High security High specificity

58 July 2009 Darrell M. Wilson, MD (Stanford)Slide 58Submission Doc: What we would like to see in a Body Area Network Bidirectional communications between devices with confirmation and error checking Reasonable transmission range –thru the body at least Monitoring of BAN status Fails safely with clear warnings

59 July 2009 Darrell M. Wilson, MD (Stanford)Slide 59Submission Doc: What we would like to see in a Body Area Network Easily interrogated (downloadable) –Cell phone, internet

60 July 2009 Darrell M. Wilson, MD (Stanford)Slide 60Submission Doc: What we would like to see in a Body Area Network Privacy and safety Privacy vs safety

61 July 2009 Darrell M. Wilson, MD (Stanford)Slide 61Submission Doc: What we would like to see in a Body Area Network And of course –Cheap –Low energy requiring –Long lasting –Green –Easy to use Thanks!


Download ppt "July 2009 Darrell M. Wilson, MD (Stanford)Slide 1Submission Doc: 15-09-0537-00-0006 July 2009 Slide 1 Project: IEEE P802.15 Working Group for Wireless."

Similar presentations


Ads by Google