INTRODUCTION TO CONTINUOUS GLUCOSE MONITORS

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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 April
2010
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Agenda

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

Barbara Davis Center for Childhood Diabetes April
2010
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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
April 2010
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Who Should Use a CGM?

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

Understanding Pumps and CGMs, p.100
Barbara Davis Center for Childhood Diabetes April
2010
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WHY Use CGM?

1. Prevention of low blood sugars (alarms)
2. Prevention of high blood sugars (ketones)
3. Minimize wide glucose fluctuations
4. Behavior Modification
5. Prevention of Complications (?)

Barbara Davis Center for Childhood Diabetes April
2010
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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)

(i) Beregszaszi M, et al. J Pediatr. 131, 27,
1997 (ii) Porter PA, et al. J. Pediatr. 13, 366,
1997
Barbara Davis Center for Childhood Diabetes April
2010
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WHY Use CGM?

1. Prevention of low blood sugars (alarms)
2. Prevention of high blood sugars (ketones)
3. Minimize wide glucose fluctuations
4. Behavior Modification
5. Prevention of Complications (?)

Barbara Davis Center for Childhood Diabetes April
2010
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Snapshot of BG levels
Barbara Davis Center for Childhood Diabetes April
2010
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Continuous Glucose Monitoring
Barbara Davis Center for Childhood Diabetes April
2010
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Hyperglycemia is common, especially after meals
50
40
30
Breakfast
Lunch
20
Dinner
10
0
Boland et al, Diabetes Care 241858, 2001
Barbara Davis Center for Childhood Diabetes April
2010
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WHY Use CGM?

1. Prevention of low blood sugars (alarms)
2. Prevention of high blood sugars (ketones)
3. Minimize wide glucose fluctuations
4. Behavior Modification
5. Prevention of Complications?

Barbara Davis Center for Childhood Diabetes April
2010
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Three Parts to CGMs

1. Sensor
2. Transmitter
3. Receiver/Monitor

Understanding Pumps and CGMs, p.103
Barbara Davis Center for Childhood Diabetes April
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• Sensor
• (p.103)

Barbara Davis Center for Childhood Diabetes April
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B) Transmitter (p.103)
Barbara Davis Center for Childhood Diabetes April
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C) Receiver or Monitor (p.103)
Barbara Davis Center for Childhood Diabetes April
2010
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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 April
2010
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What type of data will we get?

• Two types of CGM data
• Real Time data seen on CGM
• Retrospective data download to a computer

Barbara Davis Center for Childhood Diabetes April
2010
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Real Time Data

• Three types of Real Time Data
• A) Trend graphs
• B) Alarms
• C) Trend Arrows
• Understanding Pumps and CGM pages 109-113
• Barbara Davis Center for Childhood Diabetes April
  2010

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TREND GRAPHS
Real Time data
Trend graphs Knowing a glucose level is 240
mg/dl may not be as important as knowing the
trend.
Understanding Pumps and CGM p.103
Barbara Davis Center for Childhood Diabetes
April 2010
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ALARMS
Real Time data
Warn patients of current or projected high and
low blood sugar
Barbara Davis Center for Childhood Diabetes April
2010
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Alarms continued
Real Time data

• Threshold alarm
• Warning when glucose is
• above or below a set value
• --all devices have this
• Projected Alarms
• 10,20 or 30 minute warning of
• Impending hypo- or hyperglycemia
• Real-Time Revel System, Guardian Real-Time and
  the Navigator have these

Barbara Davis Center for Childhood Diabetes April
2010
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Real Time data
TREND ARROWS
Arrows that indicate the rate and direction of
change
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 April
2010
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Retrospective Data

• Three types of Retrospective data
• (viewed on computer download)
• Trend graphs
• Pie charts
• Data tables

Understanding Pumps and CGMs, Chapter 17
Barbara Davis Center for Childhood Diabetes
April 2010
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A) Trend Graphs
Retrospective data

• Reports that show one or more days of CGM data
  also called sensor overlay

Barbara Davis Center for Childhood Diabetes
August 2009
Barbara Davis Center for Childhood Diabetes April
2010
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Retrospective data
Case StudyUsing Trend Graphs

• Three Trend Graphs showing change over time
• 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

Barbara Davis Center for Childhood Diabetes April
2010
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Retrospective data
BASELINE GLUCOSE Trend Graph 1Prior to CGM Use
Barbara Davis Center for Childhood Diabetes April
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Glucose Trend Graph 2After three months of CGM
use
Retrospective data
Barbara Davis Center for Childhood Diabetes April
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GLUCOSE Trend Graph 3 Most recent CGM report
Retrospective data
Barbara Davis Center for Childhood Diabetes April
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B) PIE CHARTS
Retrospective data

• Show percentage of time glucose is above,
• below and in target range

Barbara Davis Center for Childhood Diabetes April
2010
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C) Data Tables
Retrospective data

• Show statistical information about different
  periods of the day

Barbara Davis Center for Childhood Diabetes April
2010
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USING CGM RESULTS
(To make insulin adjustments)

• Important not to get overwhelmed by data
• Make One Change At A Time
• Look for patterns 2 out of 3 days
• A behavior modification device ? Missed boluses,
  snacking, low BGs on CGM
• Good initial communication with HCP

Barbara Davis Center for Childhood Diabetes April
2010
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Interpreting CGM data
Barbara Davis Center for Childhood Diabetes April
2010
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Interpreting CGM data
Barbara Davis Center for Childhood Diabetes April
2010
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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 April
2010
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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 April
2010
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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

Barbara Davis Center for Childhood Diabetes April
2010
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Realistic Expectations of CGM
You will still experience low and high blood
sugar levels

• There will ALWAYS be some lows and highs
• 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 April
2010
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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 April
2010
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Realistic Expectations of CGM
The most significant improvements will be seen
with consistent CGM wear ( gt6 days/week)

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

Barbara Davis Center for Childhood Diabetes April
2010
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Questions?

• Next Device Information from
• the nurses
• Hands on with CGM devices

Barbara Davis Center for Childhood Diabetes April
2010
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CGMs availableApril 2010
Barbara Davis Center for Childhood Diabetes April
2010
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Paradigm Real Time systems(Paradigm pump and
Revel pump)

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

Barbara Davis Center for Childhood Diabetes April
2010
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Paradigm Real-Time system(Paradigm pump and
Revel pump)

• Pump is not controlled by CGM readings
• No extra receiver to carry
• Has high and low alarms
• Revel has predictive alarms
• Sensors last 3 days (6 days)
• Calibrations every 12 hours
• Great online download

Barbara Davis Center for Childhood Diabetes April
2010
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Guardian Real Time

• For people not using a pump
• Has high and low alarms
• Has predictive alarms
• Sensor lasts 3 days (6 days)
• Calibrations every 12 hours
• Why not buy a pump?

Barbara Davis Center for Childhood Diabetes April
2010
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Navigator CGM
Barbara Davis Center for Childhood Diabetes April
2010
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Navigator CGM

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

Barbara Davis Center for Childhood Diabetes April
2010
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DexCom 7 Plus
Barbara Davis Center for Childhood Diabetes April
2010
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DexCom 7 Plus

• Most simple system to use
• Smallest transmitter
• Has high and low alarms
• Has rate of change alarms
• Sensor lasts 7 days
• Calibrations every 12 hours
• Basic download software

Barbara Davis Center for Childhood Diabetes April
2010
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MiniMed Guardian MiniMed Paradigm 522/722 Freestyle Navigator Dexcom Seven Plus
Sensor life 3 days 3 days 5 days 7 days
Initial calibration period 2 hours 2 hours 10 hours 2 hours
Number of calibrations 2-4 per day 2-4 per day 4 in 5 days 2-4 per day
Trend arrows Yes Yes Yes Yes
High/low alarms Yes Yes Yes Yes
Predictive high/low alarms Yes No-Paradigm Real-time Yes-Revel pump Yes Rate of change alarms
Cost 1300 system 35/sensor 1000 system 722/522 insulin pump 35/sensor 1000 system 35-50/sensor 400-800 system 60/sensor
Barbara Davis Center for Childhood Diabetes April
2010
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CGM Reimbursement

• Family will fill out an Authorization to release
  insurance information
• Physician will write prescription
• (Letter of Medical Necessity)
• BDC will provide any other paperwork requested by
  the insurance company
• Call Mireya at BDC to get started
• phone [phone], fax [phone]

Barbara Davis Center for Childhood Diabetes April
2010
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Websites

• Paradigm REAL-Time, Paradigm REAL-time Revel and
• Guardian REAL-time
• www.minimed.com 1-866-948-6633
• Navigator
• www.abbottdiabetescare.com 1-888-522-5226
• Dexcom
• www.dexcom.com
  1-877-339-2664

Barbara Davis Center for Childhood Diabetes April
2010
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CGM Start and Follow up

• Medtronic Device Training
• Contact Mireya at 303-724-6763 to schedule
• Navigator Training
• Trainer will contact you when your device ships
• Dexcom Training
• Contact Michelle Perrot at 720-878-4099
• Follow up CGM with Stephanie Kassels, FNP
• call Dahlia at 303-724-6748 to schedule

Barbara Davis Center for Childhood Diabetes April
2010