INTRODUCTION TO CONTINUOUS GLUCOSE MONITORS

1
INTRODUCTION TO CONTINUOUS GLUCOSE MONITORS

• H. Peter Chase, MD
• Vicky Gage, RN, CDE
• Laurel Messer, RN, CDE
• Susie Owen, RN, CDE
• Sally Sullivan, RN, CDE

Barbara Davis Center for Childhood Diabetes
August 2009
2
Agenda

• Dr. Chase will present a general CGM overview
• Nurses will explain device features and
  comparisons between sensors
• You will have opportunity to handle each device
  and ask questions

3
What is a CGM? (Continuous Glucose Monitor)

• A device that provides real-time glucose
  readings and data about trends in glucose levels
• Reads the glucose levels under the skin every 1-5
  minutes (10-15 minute delay)
• Provides alarms for high and low glucose levels
  and trend information
• The 3rd era in diabetes management

Barbara Davis Center for Childhood Diabetes
August 2009
4
Who Should Use a CGM?

• The person and the family must both want a CGM
• A youth must be willing to wear the sensor (and
  carry the receiver)
• Using good diabetes care (4 BGs/day)
• Good support system
• Adequate body real estate
• Cost of CGM (RNs to elaborate)

(Understanding Pumps and CGMs, p.100)
Barbara Davis Center for Childhood Diabetes
August 2009
5
Continuous Glucose Monitoring (CGM) WHY?

• Prevention of low blood sugars (alarms)
• Prevention of high blood sugars (ketones)
• Minimize wide glucose fluctuations
• Behavior Modification
• Prevention of Complications (?)

Barbara Davis Center for Childhood Diabetes
August 2009
6
How common are glucose levels lt60mg/dl during the
night in children with T1D?

• French (i) and Australian (ii) data showed
  approximately 50 of children with low BG
  (lt60mg/dl) during the night (on NPH bid)
• DirecNet data (one night in hospital with blood
  sugars every 30 min.)
• A) 2001-2002 39 of 91 (43) low BG
• (44 of children on insulin pumps/56 on NPH)
• B) 2004 14 of 50 (28) with low BG
• (all on insulin pumps or Lantus)

• Beregszaszi M, et al. J Pediatr. 131, 27, 1997
• Porter PA, et al. J. Pediatr. 13, 366, 1997

Barbara Davis Center August 2009
7
Continuous Glucose Monitoring (CGM) WHY?

• Prevention of low blood sugars (alarms)
• Prevention of high blood sugars (ketones)
• Minimize wide glucose fluctuations
• Behavior Modification
• Prevention of Complications (?)

Barbara Davis Center for Childhood Diabetes
August 2009
8
Snapshot of BG levels
Barbara Davis Center for Childhood Diabetes
August 2009
9
Continuous Glucose Monitoring
Barbara Davis Center for Childhood Diabetes
August 2009
10
Hyperglycemia is common, especially after meals
50
40
30
Breakfast
Lunch
20
Dinner
10
0
Barbara Davis Center August 2009
Boland et al, Diabetes Care 241858, 2001
11
Continuous Glucose Monitoring (CGM) WHY?

• Prevention of low blood sugars (alarms)
• Prevention of high blood sugars (ketones)
• Minimize wide glucose fluctuations
• Behavior Modification
• Prevention of Complications?

Barbara Davis Center for Childhood Diabetes
August 2009
12
Three Parts to All CGMs

• Sensor
• Transmitter
• Receiver/Monitor

(Understanding Pumps and CGMs, p.103)
Barbara Davis Center for Childhood Diabetes
August 2009
13

• Sensor
• (p.103)

Barbara Davis Center for Childhood Diabetes
August 2009
14
B) Transmitter (p.103)
Barbara Davis Center for Childhood Diabetes
August 2009
15
C) Receiver or Monitor (p.103)
Barbara Davis Center for Childhood Diabetes
August 2009
16
What does Calibration mean and why do I need to
do it?

• Calibration is a process that gives a fingerstick
  BG value to the CGM system so the values will
  align with each other
• Number of Calibrations vary by device
• Best times to calibrate are when the BG values
  are stable before meals and
• before bed
• Do not calibrate when arrows are present

Barbara Davis Center for Childhood Diabetes
August 2009
17
What type of data will we get?

• Real-time (Immediate)
• i. Trend graphs (p.109)
• ii. Alarms (p.110)
• iii. Trend arrows (p.113)

Barbara Davis Center August 2009
(Understanding Pumps and CGMs)
18
i) TREND GRAPHS
Trend graphs Knowing a glucose level is 240
mg/dl may not be as important as knowing the
trend.
(Understanding Pumps and CGMs, p.103)
Barbara Davis Center for Childhood Diabetes
August 2009
19
ii) ALARMS (p.109) Can warn patients of current
or projected high and low blood sugar

• Projected alarms 10, 20, or 30 minute warning of
  impending hypo- or hyperglycemia
  (Navigator and Guardian devices)
• Threshold alarms warning when glucose is below
  or above a set value (all devices)

Barbara Davis Center for Childhood Diabetes
August 2009
20
iii) TREND ARROWS (p.110)Rate of Change Arrows
Gives the up-to-the-minute glucose value and a
rate of change arrow
Glucose rising quickly gt2 (mg/dL)/min
Glucose going up 1 to 2 (mg/dL)/min
Fairly stable glucose -1 to 1 (mg/dL)/min
Glucose going down -1 to -2 (mg/dL)/min
Glucose falling quickly gt-2 (mg/dL)/min
Barbara Davis Center for Childhood Diabetes
August 2009
21
Second type of data(Retrospective, must
download)

• 2) Retrospective
• Modal Day Graphs (p.113)
• Pie Chart (p.114)
• Statistics (p.113)

(Understanding Pumps and CGMs, Chapter 17, p.109)
Barbara Davis Center for Childhood Diabetes
August 2009
22
A) Case StudyModal Day Graphs

• Teenager with T1D for 9.5 years
• Started Navigator Sept. 2005
• Starting HbA1c 7.1
• Most recent HbA1c 6.0
• Current number of low BGs per week (lt60 mg/dL or
  lt3.3 mmol/L) 1/week
• Three modal-day graphs

(Understanding Pumps and CGMs, p.113)
Barbara Davis Center for Childhood Diabetes
August 2009
23
A) BASELINE GLUCOSE MODAL DAYi) Prior to
Navigator Use
Barbara Davis Center for Childhood Diabetes
August 2009
24
A) GLUCOSE MODAL DAYBreakfast/Lunch
Improvementsii) After three months of use
Barbara Davis Center for Childhood Diabetes
August 2009
25
A) GLUCOSE MODAL DAYiii) Most recent report
Barbara Davis Center for Childhood Diabetes
August 2009
26
B) PIE CHARTS (p.114)
Barbara Davis Center for Childhood Diabetes
August 2009
27
C) STATISTICS (p.113)
Barbara Davis Center for Childhood Diabetes
August 2009
28
USE OF CGM RESULTS
(To fine-tune insulin and diabetes management)

• Important not to overwhelm families
• One change at a time
• Look for patterns 2 out of 3 days
• A behavior modification device ? Missed boluses,
  snacking, low BGs on CGM
• iv) Good initial communication with HCP

Barbara Davis Center for Childhood Diabetes
August 2009
29
Interpreting CGM data
30
Interpreting CGM data
31
Realistic Expectations of CGM

• You will still need to test your blood sugar
  levels
• Using CGM does not make Diabetes Management a
  Breeze
• You will still experience low and high blood
  sugar values
• Sensor values will not always MATCH the blood
  sugar values
• The most significant improvements will be seen
  with consistent CGM wear

Barbara Davis Center for Childhood Diabetes
August 2009
32
Realistic Expectations of CGM
You will still need to test your
blood sugar levels for

• Calibrations
• Insulin dosing
• Treating high and low blood sugar levels
• Questioning the accuracy of the CGM values
• Times when you do not feel right

Barbara Davis Center for Childhood Diabetes
August 2009
33
Realistic Expectations of CGM

• Using CGM does not make Diabetes Management a
  Breeze

• Initially, people are overwhelmed from all the
  data
• Subjects will follow an algorithm early on in the
  use of CGM
• Family weekly downloads of CGM data are important
• CGM works as a behavior modification device

34
Realistic Expectations of CGM
You will still experience low and high blood
sugar levels

• There will ALWAYS be some highs and lows
• Alarms may not be sensitive to slowly falling
  blood sugar values
• The time spent in hypoglycemia and hyperglycemia
  can be reduced
• CGM is an additional tool to help make decisions
• CGM values are not very helpful in treating lows

Barbara Davis Center for Childhood Diabetes
August 2009
35
Realistic Expectations of CGM

• Sensor values will not always MATCH the blood
  sugar values

• CGM values are about 10 minutes behind blood
  sugar values
• Values are less accurate early after insertion
• Values are furthest off when blood sugars are
  rapidly rising or falling
• Calibrations are important determinants of
  accuracy of the CGM

Barbara Davis Center for Childhood Diabetes
August 2009
36
Realistic Expectations of CGM
The most significant improvements will be seen
with consistent CGM wear

• Good initial education helps patients and
  families to learn what to expect
• Regular use of Real-time and Retrospective data
  is necessary for optimal
• CGM benefits
• Follow up with HCP is important to continue to
  make adjustments

Barbara Davis Center for Childhood Diabetes
August 2009
37
Questions?

• The presentation by the nurses will be next.
• You will then examine the CGMs from 3 companies.

Barbara Davis Center for Childhood Diabetes
August 2009
38
CGMs availableAugust 2009
Barbara Davis Center for Childhood Diabetes
August 2009
39
Paradigm Real Time system

• A Insulin pump and CGM receiver
• B Infusion set
• C Sensor
• D Transmitter

Barbara Davis Center for Childhood Diabetes
August 2009
40
Paradigm Real Time system

• PUMP and CGM DO NOT COMMUNICATE
• Do not have to carry around extra receiver
• Sensors last 3 days (6 days)
• Calibrations every 12 hours
• High and low alarms
• Insertion is at 45 angle
• Great online download

Barbara Davis Center for Childhood Diabetes
August 2009
41
Guardian Real Time

• For people not on insulin pumps
• Has high/low alarms and predictive high/low
  alarms
• Calibrations every 12 hours
• Why not get pump and only use CGM piece?
  

Barbara Davis Center for Childhood Diabetes
August 2009
42
Navigator CGM
Barbara Davis Center August 2009
43
Navigator CGM

• Has built in Freestyle BG meter
• Has high/low alarms and predictive high/low
  alarms
• Sensors last 5 days
• Calibrations done at 10, 12, 24,
  and 72 hours
• Larger transmitter
• Well studied, highly
  accurate

Barbara Davis Center for Childhood Diabetes
August 2009
44
DexCom 7 Plus
Barbara Davis Center for Childhood Diabetes
August 2009
45
DexCom 7 Plus

• Most simple system to use
• Smallest transmitter
• Sensor lasts 7 days
• Calibrations every 12 hours
• Glucose trend arrows
• High and low alarms and alerts
• Basic download software

Barbara Davis Center for Childhood Diabetes
August 2009
46
Barbara Davis Center for Childhood Diabetes
August 2009
47
CGM Reimbursement

• Family will fill out forms
• HCP will write prescription
• Letter written to your insurance company
• If the product is denied then a 2nd letter will
  be written to the insurance company
• Family option to purchase their own product

Barbara Davis Center for Childhood Diabetes
August 2009
48
Websites

• Paradigm Real-Time and Guardian
• www.minimed.com 1-866-948-6633
• Navigator
• www.abbottdiabetescare.com 1-888-522-5226
• Dexcom
• www.dexcom.com
  1-877-339-2664
• BDC contact information
• Fax [phone]
• Bridgette Turley 303-724-6763

Barbara Davis Center for Childhood Diabetes
August 2009