A Patient Safety Initiative For Insulin Pumps

1
A Patient Safety Initiative For Insulin Pumps
Manufacturing Standards to improve insulin pump
safety and medical outcomes Suggestions for
improvements and editorial changes are welcome.
Send comments to John Walsh, PA, CDE at
jwalsh_at_diabetesnet.com and Ruth Roberts, MA
rroberts_at_diabetesnet.com [phone]
Version 2 09/28/09Version 1 12/07/08
2
Definitions

• TDD total daily dose of insulin (all basals and
  boluses)
• Basal background insulin pumped slowly through
  the day to keep BG flat
• Bolus a quick surge of insulin as
• Carb boluses to cover carbs
• Correction boluses to lower high readings that
  arise from too little basal insulin delivery or
  insufficient carb boluses
• Bolus On Board (BOB) the units of bolus insulin
  with glucose-lowering activity still working from
  recent boluses
• Duration of Insulin Action (DIA) time that a
  bolus will lower the BG. This is used to
  calculate BOB.

3
Background

• Although insulin pumps were first designed to
  improve insulin delivery, new technology has
  transformed them into data collection centers.
  Additional data from continuous glucose
  monitoring devices increases the datas value.
• Data necessary for monitoring and clinical
  decisions is now directly accessible in the pump
  itself. With regular glucose testing and data
  analysis, a pump can provide important clinical
  information to users and clinicians regarding
  glucose and insulin dosing patterns with
  recommendations for improvement.

Pump collectively refers to the pump body,
PDA, cell phone, and other devices that control
insulin delivery and store data.
4
Introduction

• Over 500,000 insulin pumps are in use around the
  world, yet there are no formal guidelines
  regarding manufacturing standards and medical
  practice in the diabetes clinical community and
  pump manufacturing industry.
• These suggested standards are intended as
  imprements for future insulin pumps and in
  current pumps where software changes allow.
• They are designed to
• Provide safer dosing increments and problem
  solving to pump users
• Allow clinicians to make safer and more informed
  dosing decisions when managing a variety of pumps
• Facilitate the training of adjunctive medical and
  accessory personnel (ER, surgical, school nurses,
  etc.) to improve their familiarity and
  interactions with insulin pumps

5
Benefits Of Insulin Pump Standards

• These mechanical standards are designed for
• Consistent use of pump settings between pump
  manufacturers
• Accuracy and safety of carb and correction factor
  increments
• Safety of DIA defaults and consistent use of DIA
  increments
• Consistent handling of BOB and insulin stacking
• Improved monitoring for hypoglycemia
  hyperglycemia
• Direct entry of glucose values into bolus
  calculations
• Notification when use of correction boluses is
  excessive
• Faster identification of control issues caused by
  infusion sets

6
Overview
Slides are numbered by topic for easy reference.

• Topic
• Carb Factor Increments
• Correction Factor Increments
• Carb Factor Accuracy
• Correction Factor Accuracy
• DIA Default Times
• DIA Time Increments
• Handling Of BOB

Topic 8. Multi-Linear And Curvilinear DIA
9. Hypoglycemia Alert 10. Hyperglycemia
Alert 11. Correction Bolus Alert 12. Insulin
Stacking Alert 13. Automatic Entry Of BG
Values 14. Infusion Set Monitoring
7
Safety

• Increments and Accuracy
• Carb factor
• Correction factor
• DIA
• Defaults
• DIA
• Handling Of BOB
• Hypo Manager

• Topic
• Alerts
• Hypo frequency
• Hyper frequency
• Unusual highs
• Correction Bolus Excess
• Insulin Stacking
• Overview table of alert frequency
• 13. Infusion Set Monitor

8
Easy Data Access

• BOB
• TDD
• Correction bolus
• Carb bolus
• Basal
• Avg glucose
• SD
• Carbs/day with approximate calorie equivalent

• Accurate carb and correction factors
• Automatic basal and factor testing
• How often bolus recommendation is overridden and
  direction
• Frequency of occlusions and stops (and length of
  stops)

9
ReviewChange in TDD Changes The BG

• For some later slides, it helps to know how a
  change in the TDD affects the glucose levels.
• Using a modified Davidson Rule for the carb
  factor and a 2000 Rule for the correction factor
• 1.25 change in the TDD changes glucose levels
  about 25 mg/dl when given as a single dose
• A 5 change in the TDD is equivalent to about a
  25 mg/dl rise or fall in the glucose through the
  day
• A 5 to 6 change in the carb factor (approx. 2.5
  to 3 of the TDD) changes the glucose about 20
  mg/dl per meal.

10
Carb Factor Increments
1
Carb Factor (CarbF) the number of grams of carb
covered by 1 u of insulin for an individual The
smaller the carb factor, the larger a carb bolus
11
1
Standard For Carb Factor Increments

• Carb factor increments shall be less than or
  equal to 5 of the next larger whole number so
  that each single step adjustment causes
  subsequent carb boluses to change by no more than
  5 from previous doses.
• Recommended minimum carb factor increments 5
• 1.0 g/u above 20 g/u
• 0.5 g/u for 10 to 20 g/u
• 0.2 g/u for 5 to 9.8 g/u
• 0.1 g/u for 3 to 4.9 g/u
• 0.05 g/u for 0.1 to 2.95 g/u

5 Improved carb factor increments recommended by
Gary Scheiner, MS, CDE
12
Carb Factor (CarbF) Increments
1

• Issue Existing carb factor increments are too
  large.
• Current carb factors are a safety concern because
  they lack the precision required to avoid
  excessive hyperglycemia and hypoglycemia,
  especially for smaller carb factor numbers.

13
ExampleCarb Factor Increments
1

• 1 gram per unit is the smallest CarbF increment
  in most pumps. This increment is relatively large
  for CarbFs lower than 15 or 20 g/u.
• For instance, when the carb factor is reduced
  from 10 to 9 g/u, all subsequent carb boluses are
  increased by 11.1. A shift in the carb factor
  from 1u/5g to 1u/4g causes each subsequent carb
  bolus to increase by 25.
• For most pump users, a change in carb factor of 5
  to 6 causes the average glucose to rise or fall
  by at least 20 mg/dl after all meals.

14
ExampleImpact On BG From CarbF Adjustment
1

• Table shows average additional fall in glucose
  when a carb factor is reduced from 10 gram/u to 9
  gram/u.

More carbs greater glucose fall
Calculated as carbs in meal carbs in
meal X 1900 new carb
factor old carb factor TDD
15
ReviewMedian Carb Factor
1

• In unpublished data from the Cozmo Data Analysis
  Study for 135 pump users in good control (avg BG
  144.0 mg/dl with 4.92 tests/day)
• The average carb factor was 10.4 g/u
• Nearly all use a carb factor below 20 g/u
• Almost 50 of carb factors are 10.0 g/u or less.
• The smaller the carb factor, the more vulnerable
  the pumper is to error when an increment is
  changed

Authors unpublished data from subset of over
1,000 complaint-free insulin pumps turned in for
software upgrade in 2007.
16
What Current Changes In CarbFs Do
1

• Table shows how subsequent carb boluses are
  affected by a one-step reduction in the CarbF
  using different CarbF increments. Yellow area
  shows values for most current pumps. Green areas
  show safer increments that impact subsequent
  boluses less than 5.

17
Correction Factor Increments
2
Corr Factor (CorrF) the number of mg/dl (mmol)
drop in glucose that is produced by 1 u of
insulin for an individual The smaller the corr.
factor, the larger a corr. bolus
18
2
Standard For Correction Factor Increments

• For similar reasons, correction factor increments
  shall be 5 or less of the next larger whole
  number so that each single step adjustment causes
  subsequent correction boluses to change by no
  more than 5 from previous doses.
• Recommended minimum correction factor increments
  
• 5.0 mg/dl per u above 80 mg/dl per u
• 2.0 mg/dl per u for 40 to 78 mg/dl per u
• 1.0 mg/dl per u for 20 to 39 mg/dl per u
• 0.5 mg/dl per u for 10 to 19.5 mg/dl per u
• 0.2 mg/dl per u for 5 to 9.8 mg/dl per u
• 0.1 mg/dl per u for 3 to 4.9 mg/dl per u
• 0.05 mg/dl per u for 0.1 to 2.95 mg/dl per u

19
Carb Factor Accuracy
3
Carb Factors are often not physiologically
appropriate
20
3
Standard For Verification Of Carb Factor Accuracy

• Insulin pump companies shall record and publish
  each year the carb factors used in insulin pumps
  returned for upgrade or repair. This report will
  include sufficient numbers of pumps to ensure
  statistical significance for commonly used carb
  factors between 5 and 20 grams per unit.
• This data is designed to ensure that pump
  training and clinical followup are assisting in
  the selection of accurate carb factors.
• To improve accuracy of carb factors, efforts
  shall be taken to better train clinicians and
  users in appropriate selection of physiologic
  carb factors.

21
Personal Carb Factors
3

• Issue Many carb factor settings in todays
  insulin pumps today are physiologically
  inappropriate.
• Inappropriate carb factors introduce a
  significant source for error in carb bolus
  calculations.

22
Review Carb Factors In Use 1
3
10
7
115
20

• Carb factor settings from 405 Cozmo pumps do NOT
  have a bell-shaped (physiologic) distribution.
  Easy numbers 5, 10, 15, and 20 g/unit are
  preferred.

1
23
Correction Factor Accuracy
4
24
4
Standard For Verification Of Corr Factor Accuracy

• Insulin pump companies shall record and publish
  each year the correction factors used in insulin
  pumps returned for upgrade or repair. This report
  will include sufficient numbers of pumps to
  ensure statistical significance for commonly used
  correction factors between 20 and 80 mg/dl per
  unit.
• This data is designed to ensure that pump
  training and clinical followup are assisting in
  the selection of accurate correction factors.
• For more accurate selection of corr. factors,
  efforts shall be taken to improve corr. factor
  selection and to automate corr. factor testing.

25
Personal Correction Factors
4

• Issue Many correction factors used in insulin
  pumps today are poorly tuned to the users need.
  This inaccuracy significantly magnifies other
  sources of error in correction bolus
  calculations.

26
Review Correction Factors In Use 1
4

• Avg. correction factors in use for 452
  consecutive Cozmo insulin pump downloads
• Like carb factors, correction factors in use are
  NOT bell-shaped or physiologic. A more accurate
  choice of correction factors would create a
  bell-shaped curve.
• Users or clinicians appear to frequently select
  magic numbers for correction factors.

10
7
115
20
1
27
DIA Default Times
5
28
Standard ForDIA Default Times
5

• Default duration of insulin action (DIA) times in
  current pumps vary between 3 and 6 hours. In
  bolus calculations, a short DIA time shall be set
  no shorter than 4.5 hours in pumps that determine
  DIA in a linear fashion and no shorter than 5
  hours in pumps that determine DIA in a
  curvilinear or multi-linear fashion for fast
  insulins (lispro, aspart, and glulisine) in use
  at this time.

29
DIA Default Time Settings
5

• Issue DIA measures the glucose-lowering activity
  of a carb or correction bolus over time. Current
  default times for DIA range from 3 to 6 hours in
  different pumps.
• The DIA is often considered another tool to
  improve control rather than being set at an
  appropriate value and focusing on more
  appropriate changes in basal rates or carb and
  correction factors to improve control.
• A DIA that is too short allows excess
  unrecognized bolus insulin to accumulate, usually
  in the afternoon and evening hours.
• Example for a DIA of 2.5 hrs, a bolus given at 9
  am appears to have no activity after 1130 am. If
  a high BG occurs at 1145 am, more bolus than
  needed will be given. At lunch, the bolus will be
  excessive, regardless of the BG at that time,
  creating stacking and a high likelihood of
  hypoglycemia.

30
ReviewHow Long Do Boluses Lower The BG?
5

• Numerous GIR studies show rapid insulins lower
  the glucose for 5 hours or more.
• With Novolog (aspart) at 0.2 u/kg (0.091 u/lb),
  23 of glucose lowering activity remained after 4
  hours.12
• Another study found Novolog (0.2 u/kg) lowered
  the glucose for 5 hours and 43 min. /- 1 hour.13
• After 0.3 u/kg or 0.136 u/lb of Humalog (lispro),
  peak glucose-lowering activity was seen at 2.4
  hours and 30 of activity remained after 4 hours.
  11
• These times would be longer if the unmeasured
  basal suppression in pharmacodynamic studies were
  accounted for.

11 From Table 1 in Humalog Mix50/50 product
information, PA 6872AMP, Eli Lilly and Company,
issued January 15, 2007. 12 Mudaliar S, et al
Insulin aspart (B28 Asp-insulin) a fast-acting
analog of human insulin. Diabetes Care 1999
221501-1506. 13 L Heinemann, et al Time-action
profile of the insulin analogue B28Asp. Diabetic
Med 199613683-684.
31
ReviewShort DIAs Hide Bolus Insulin Activity
5

• A short DIA time hides true BOB level and its
  glucose-lowering activity. This can be a safety
  issue in that it
• Leads to unexplained lows
• Leads to incorrect adjustments in basal rates,
  carb factors, and correction factors
• Causes users to start ignoring their smart
  pumps advice
• An inappropriately long DIA time overestimates
  bolus insulin activity this leads to
  underdosing rather than overdosing on subsequent
  boluses.
• DIA should be based on an insulins real action
  time.
• Do NOT modify the DIA time to fix a control
  problem

32
ReviewDuration Of Insulin Action (DIA)
5
Accurate bolus estimates require an accurate DIA.
DIA times shorter than 4.5 to 7 hrs may hide BOB
and its glucose lowering activity
Glucose-lowering Activity
6 hrs
2 hrs
0
4 hrs
33
ReviewDIA
5

• Large doses (0.3 u/kg 30 u for 220 lb. person)
  of rapid insulin in 18 non-diabetic, obese
  people
• Med. doses (0.2 u/kg 20 u for 220 lb. person)
• This shows a glucose lowering activity for 7-8
  hours

Regular
Apidra product handout, Rev. April 2004a
34
ReviewDoes Dose Size Affect DIA?
5

• This graphic suggests that smaller boluses do not
  lower the BG as long as larger boluses.
• However, this may not be true see next 2
  slides.
• Size of the injected Humalog dose for a 154 lb or
  70 kg person
• 0.05 u/kg 3.5 u
• 0.1 u/kg 7 u
• 0.2 u/kg 14 u
• 0.3 u/kg 21 u

Woodworth et al. Diabetes. 199342(Suppl. 1)54A
35
ReviewPharmacodynamics Is Not DIA
5

• The DIA time entered into an insulin pump is
  based on studies of insulin pharmacodynamics.
• However, the traditional method used to determine
  insulin pharmacodynamics may underestimate
  insulins true duration of action, as shown in
  the next two slides.

36
ReviewPharmacodynamics Underestimates DIA And
Overestimates Impact Of Bolus Size
5

• To measure pharmaco-dynamics, glucose clamp
  studies are done in healthy individuals who
  receive an injection of fast insulin (0.05 to 0.3
  u/kg)
• Because there is no basal insulin replacement,
  the injected insulin dose ALSO SUPPRESSES normal
  basal release from the pancreas (grey area in
  figure)

37
ReviewPharmacodynamic Time Does Not Equal DIA
5

• After accounting for the lack of basal insulin
  replacement,
• True DIA times become longer than the PD times
  derived in traditional research
• If basal suppression activity is accounted for,
  small boluses may be found to have a longer DIA
  than it currently appears, erasingsome of the
  apparent variation in DIA related to bolus size
• Some of the apparent inter-individual variation
  in pharmacodynamics may also disappear

38
DIA Time Increments
6
39
6
Standard For DIA Time Increments

• For safe and accurate estimates of residual BOB,
  DIA time increments shall be no greater than 15
  minutes.

40
DIA Time Increments
6

• Issue Current DIA time increments vary from 15
  minutes to 1 hour in different pumps
• When a pumps DIA time is adjusted, large time
  increments, such as 1 hr, can introduce large
  changes in subsequent estimates of BOB.
• For example, when the DIA is reduced from 5 hours
  to 4 hours, subsequent BOB estimates are
  decreased and recommendations for carb boluses
  are increased by about 25.

41
ReviewGlucose Infusion Rate (GIR) Studies
6

• Most GIR studies suggest that pharmacodynamic
  action of insulin varies only about 25 to 40
  between individuals.
• For a DIA time of 5 hr and 15 min, a 25 range is
  equivalent to 1 hr and 20 min, such as from 4 hrs
  and 30 min to 5hr and 50 min.
• A pump that has 1 hr DIA increments would enable
  the user to select only 1 or 2 settings within
  this physiologic range, while a 30 min increment
  would allow only 2 or 3 choices that are close to
  a physiologic range.

42
Handling Of BOB
7

• Bolus On Board (BOB)

aka insulin on board, active insulin, unused
insulin Introduced as Unused Insulin in 1st ed
of Pumping Insulin (1989)
43
Standard ForHandling Of BOB
7

• For safe and accurate BOB measurement
• BOB measurements shall include all carb and
  correction boluses given within the selected DIA
• When residual BOB is present at the time of a
  bolus, the BOB shall be subtracted from both carb
  and correction bolus recommendations.
• When BOB exceeds the current correction bolus
  need or the current carb plus correction need,
  the user will be alerted to how many grams of
  carb they need to eat to avert a low.(BOB
  correction carb bolus need) X carb factor

44
Handling Of BOB
7

• Issue Current pumps differ significantly in what
  is counted as BOB and in whether or not BOB is
  subtracted from subsequent carb boluses.
• Most insulin pumps assume that excess BOB does
  not need to be taken into account when
  determining the next carb bolus.
• Though commonly determined in this way, the
  resulting bolus dose recommendations can cause
  unexplained and unnecessary insulin stacking and
  hypoglycemia.

45
ExampleInsulin Stacking
7

• With a bedtime BG of 173 mg/dl,
• is there an insulin deficit or a carb deficit?

Bedtime BG 173 mg/dl
Correction
Dessert
Dinner
6 pm
8 pm
10 pm
12 am
46
ReviewFrequency Of Insulin Stacking
7

• CDA1 Study Results
• Of 201,538 boluses, 64.8 were given within 4.5
  hrs of a previous bolus
• Although 4.5 hours may underestimate true DIA,
  use of this minimal DIA time shows that some BOB
  is present for MOST boluses

4.5 hrs
47
ReviewBolus On Board (BOB)
7

• An accurate measurement of the glucose-lowering
  activity that remains from recent boluses
• Prevents insulin stacking
• Improves bolus accuracy
• Allows the current carb or insulin deficit to be
  determined

48
ReviewHow Current Pumps Handle BOB
7
Except when BG is below target BG
A Yes response is generally considered safer
49
ExampleUnsafe BOB1 Handling
7

• If a pump user gets frustrated with a high BG and
  they overdose to speed its fall, or they exercise
  longer or more intensely than anticipated, they
  can acquire a significant excess in BOB.
• In these situations, most current pumps recommend
  that a bolus be given for all carb intake
  regardless of how much BOB is actually present.
• When the BOB is larger than the correction bolus
  required at the time, the pumps bolus
  recommendation introduces an unnecessary risk of
  hypoglycemia.

1 Pumping Insulin, 1st ed, 1989, Chap 12, pgs
70-73 The Unused Insulin Rule
50
ExampleDifferences In Bolus Recommendations
7

• Situation BOB 3.0 u and 30 gr. of
  carb will be eaten at these glucose levels
• Carb factor 1u / 10 gr
• Corr. Factor 1 u / 40 mg/dl over
  100
• Target BG 100
• TDD 50 u

The graphic shows how widely bolus
recommendations vary from one pump to another for
the same situation.
units
mg/dl
Omnipod bolus cannot be determined - it counts
only correction bolus insulin as BOB
51
ReviewTrack BOB Or Carb Digestion?
7

• For safety after a bolus, it is more important to
  account for the glucose-lowering action of BOB
  than the glucose-raising action of digesting meal
  carbs
• When a BG is taken after a meal, the BOB times
  the correction factor ideally represents the
  maximum anticipated fall in glucose.
• Accounting for the impact of the BOB on the
  current glucose provides the safest approach in
  the determination of bolus recommendations.
• Low glycemic index meals, gastroparesis, Symlin,
  and other issues may counteract a predicted fall
  in glucose based on BOB, but the user can more
  easily judge and remedy this situation than
  dealing with an unknown excess of insulin.

52
Exceptions To Usual Handling Of BOB
7

• When a second bolus is taken for an unplanned
  carb intake or a desert that is consumed within
  60 minutes or so of a meal bolus, BOB should not
  be taken into account for the second bolus
  because the impact of the first bolus cannot be
  accurately determined.
• Given that, it is wise to account for BOB as soon
  after a meal as possible, such as within 60 to 90
  minutes, to provide early warning if the bolus
  given was excessive or inadequate.

Accounting for all BOB and applying it to
subsequent boluses is generally safer, although
not always more accurate.
Adjustable setting in pump/controller
53
Multi-Linear And Curvilinear DIA
8
54
Standard ForMulti-Linear And Curvilinear DIA
8

• Insulin pumps shall use either a 100 curvilinear
  or a multi-linear method to improve accuracy and
  consistency of BOB estimates.

55
ReviewLinear And Curvilinear DIA
8

• Issue Pump manufacturers use at least 3
  different methods (100 curvilinear, 95 of
  curvilinear, and straight linear) to measure DIA
  and BOB.
• When a realistic DIA time is selected, a linear
  determination of residual BOB will not be as
  accurate as a curvilinear method that
  incorporates the slow onset of insulin action and
  its longer tailing off in activity. In most
  situations, an accurate determination of
  insulins tailing activity will be most important
  to the pump user.

56
Linear And Curvilinear DIA Compared
8

• Note how values for the 5 hr linear line in red
  and the thinner 5 hr curvilinear line diverge in
  value at several points along the graph.

5 hr Linear
5 hr 95 Curvilinear
From Pumping Insulin, 4th ed., adapted fom
Mudaliar et al Diabetes Care, 22 1501, 1999
57
ExampleA Multi-Linear DIA
8

• Use of a multi-linear method to measure DIA
  improves accuracy. The next page shows a
  triple-linear example for measurement of BOB.

58
ExampleA Triple-Linear Approximation Of DIA
8

• A triple-linear line in red can more closely
  approximate a curvilinear DIA.
• For a 5 hr DIA
• 1st 10 no change
• Mid 65 fall 75
• Last 25 fall 25 ( adjustable as needed
  in device)

5 hr Triple Linear
modification suggested by Gary Scheiner, MS,
CDE
59
Hypoglycemia Analysis And Alert
9
60
Standards ForHypoglycemia Analysis And Alert
9

• Insulin pumps that store BG and insulin dosing
  data can present this BG control data in a
  readily accessible form on the pump or
  controller.
• The pump shall alert the user when the BG data
  from their glucose meter or continuous monitor
  suggests they are experiencing frequent or
  severe patterns of hypoglycemia, based on
  preselected, adjustable criteria.

Adjustable settings in pump/controller
61
Frequent/Severe Hypoglycemia Alert
9

• Issue Although most current insulin pumps
  contain sufficient data to determine when the
  user is experiencing patterns of frequent or
  severe hypoglycemia, pumps give no warning of
  this to the user.

62
ExamplePump Screen Hypoglycemia Display 1
9
To improve statistics for a better understanding
of the severity and frequency of low glucose
events over time (weeks), the pump can provide a
screen such as the following
Modified to display per Gary Scheiner, MS, CDE
Adjustable settings in pump/controller
63
ExamplePump Screen Hypoglycemia Display 2
9
The daily timing for severity and frequency of
hypoglycemia can be shown in a screen such as the
following
Modified to display per Gary Scheiner, MS, CDE
Adjustable settings in pump/controller
64
Frequent/Severe Hypoglycemia Alert
9

• Solution Depending on the settings selected by
  the user and clinician, an alert would sound when
  a pattern of more than one hypoglycemia event
  exceeds their threshold for frequency or
  severity of hypoglycemia.
• In addition, typical ways to resolve the pattern
  of hypoglycemia will be presented.

Adjustable settings in pump/controller
65
Hyperglycemia Analysis And Alert
10
66
Standards ForHyperglycemia Analysis And Alert
10

• Insulin pumps that store BG and insulin dosing
  data can present this BG control data in a
  readily accessible form on the pump or
  controller.
• The pump shall alert the user when the BG data
  from their glucose meter or continuous monitor
  suggests they are experiencing frequent or
  severe patterns of hyperglycemia, based on
  preselected, adjustable criteria.

Adjustable settings in pump/controller
67
Frequent/Severe Hyperglycemia
10

• Issue Although most current insulin pumps
  contain sufficient data to determine when the
  user is experiencing patterns of frequent or
  severe hyperglycemia, pumps give no warning of
  this to the user.

68
ExamplePump Screen Hyperglycemia Display 1
10
To improve statistics for a better understanding
of the severity and frequency of high glucose
events over time (weeks), the pump can provide a
screen such as the following
Modified to display per Gary Scheiner, MS, CDE
Adjustable settings in pump/controller
69
ExamplePump Screen Hyperglycemia Display 2
10
The daily timing for severity and frequency of
hyperglycemia can be shown in a screen such as
the following
Modified to display per Gary Scheiner, MS, CDE
Adjustable settings in pump/controller
70
Frequent/Severe Hyperglycemia Alert
10

• Solution Depending on the settings selected by
  the user and clinician, an alert would sound when
  a pattern of more than one hyperglycemia events
  exceeds their threshold for frequency or
  severity.
• In addition, typical ways to resolve the pattern
  of hyperglycemia will be presented.

Adjustable settings in pump/controller
71
Correction Bolus Alert
11
72
Standard ForCorrection Bolus Alert
11

• Insulin pumps shall show in a readily accessible
  history screen the percentage of the TDD that is
  used for correction boluses over time, and alarm
  based on preselected, adjustable criteria.
• For instance, the insulin pump shall alert the
  wearer when they use more than 8 of their TDD
  for correction bolus doses over the most recent 4
  day period.

Adjustable settings in pump/controller
73
Correction Bolus Alert
11

• Issue Hyperglycemia is more common than
  hypoglycemia for most people on insulin pumps.
• When glucose levels consistently run high, many
  pump users address the problem by giving frequent
  correction boluses rather than correcting the
  core problem through an increase in their basal
  rates or carb boluses.
• If the correction bolus becomes excessive
  relative to the TDD, the pump user is made aware
  of their excess use of correction boluses.

74
Insulin Stacking Alert
12

• Accurate accounting of the BOB is important to
  those who bolus frequently, those who experience
  frequent or severe hypoglycemia, and those whose
  average glucose levels are closer to normal
  values.

75
Standard ForInsulin Stacking Alert
12

• Insulin pumps shall alert the user when he/she
  gives a bolus and no glucose value has been
  entered in the pump, but there is sufficient
  insulin stacking to significantly alter the
  bolus they would otherwise give.
• The alert is on by default once a DIA time is
  selected to measure BOB, but may be turned off if
  the user desires.

Such as when the BOB is greater than 1.25 of
the avg. TDD, sufficient to change the glucose
about 25 mg/dl. ( Adjustable setting in
pump/controller for a certain fall in glucose
selected by the user or clinician)
76
Insulin Stacking Alert
12

• Issue Pump users often bolus for carbs without
  checking their glucose first. With no glucose
  reading, the pump cannot account for BOB, nor
  appropriately adjust a recommended bolus for the
  BOB or the current BG.
• Even though no BG test is done, data available in
  the pump when the bolus is given can inform the
  user when there is sufficient BOB to
  substantially change their bolus dose.
• The pump can alert the user to this unseen,
  substantial insulin stacking.

77
ExampleInsulin Stacking or BOB Alert
12

• When a carb bolus is planned without a recent BG
  check, but BOB is more than 1.25 of the average
  TDD (enough to cause about a 25 mg/dl drop in the
  glucose), the pump will recommend that the wearer
  do a BG check due to the substantial presence of
  BOB.
• For instance, for someone with
• Avg TDD 1.25 of TDD
• 40 units 0.5 units
• 50 mg/dl per u (corr factor) X 0.5 u 25
  mg/dl
• This individual would be alerted when they do not
  check their glucose and want to give a bolus but
  have 0.5 u or more of BOB present.

Adjustable in pump/controller for a reasonable
degree of safety
78
Automatic Entry Of BG Values
13
79
Standard ForAutomatic Entry Of BG Values
13

• For completion of the BG history, improved
  handling of BOB, and more accurate bolus
  recommendations, insulin pumps shall be enabled
  to have wireless or direct entry of BG test
  results from a glucose meter.
• Automatic glucose entry from two or more major
  brands of meters is recommended to increase the
  likelihood of insurance coverage for test strips.

80
Automatic Entry Of BG Values
13

• Issue Pump users do not enter as many BG values
  into their pump when readings must be entered
  manually rather than automatically entered from a
  meter.
• When a BG is checked but not entered, the lost
  data cannot be used to account for BOB, warn of
  insulin stacking (see 12), and are not as
  accurate when attampting to analyze glucose
  patterns or the frequency of hypoglycemia and
  hyperglycemia.
• Relatively normal and hypoglycemia values are
  less likely to be entered manually, but are more
  likely to be influenced by BOB.

81
ReviewAutomatic Entry Of BG Values
13

• In a study of over 500 insulin pumps where BG
  values could be entered either manually or
  automatically, users entered 2.6 BG values per
  day manually, compared to 4.1 values per day for
  pumps in which glucose values wre automatically
  entered.
• BOB could typically be taken into account for 1.5
  additional boluses per day with automatic entry
  of BG values.
• When glucose values are not automatically
  entered, BOB cannot be determined and bolus
  recommendations will not be as accurate.

J. Walsh, D. Wroblewski, T.S. Bailey
unpublished data
82
ReviewAutomatic Entry Of BG Values
13

• Automatic entry of glucose values into pumps
  offers a significant clinical advantage to users
  and clinicians because more boluses will be
  adjusted for high and low BGs, and residual BOB
  is more likely to taken into accout in bolus
  calculations.
• Automatic entry of glucose values (along with
  accurate accounting of BOB, see 7) ensures a
  greater degree of safety for those who experience
  frequent or sever hypoglycemia, and those whose
  glucose values are closer to normal.

83
Infusion Set Monitoring
14
84
Standards ForInfusion Sets
14

• Insulin pumps shall monitor and record in easily
  accessible history the duration of infusion set
  usage recorded as mean, median, and SD of time of
  use.
• Insulin pumps shall monitor and report average
  glucose values over 6 or 12 hour time intervals
  between set changes with the ability to change
  the observation interval, such as the last 1 to
  30 set changes.
• This monitor allows HCPs and users to identify
  infusion set problems through loss of glucose
  control related to length of set use and
  variations in length of infusion set use.

Adjustable setting in pump/controller
85
Infusion Sets
14

• Issue A significant number of pump wearers
  encounter partial or complete infusion set
  failure. Failure may arise from poor infusion set
  design or poor site preparation. Which users are
  encountering infusion set problems, how often
  infusion sets may be responsible for erratic
  glucose readings, and how significantly infusion
  set problems impact glucose control are currently
  difficult for users and clinicians to identify.

86
ReviewInfusion Set Failure
14

• Infusion set failure can arise due to occlusions
  or from a Teflon infusion set coming loose
  beneath the skin due to movement or tugging. When
  loosened, some of the infused insulin can leak
  back to the skin surface and result in
  unexplained high readings.
• A complete loss of glucose control can also occur
  when an infusion set is pulled out entirely.
• Selecting the right infusion set plus good site
  technique, especially taping the infusion line to
  the skin, can significantly minimize unexplained
  high readings for many pump wearers.

87
Why Tubing Needs To Be Taped
14

• Many problems with infusion sets come from
  loosening of the Teflon under the skin, not from
  a complete pullout. A 1 tape placed on the
  infusion line
• Stops tugging on the Teflon catheter under the
  skin
• Prevents loosening of the Teflon catheter under
  the skin
• Avoids many unexplained highs caused when
  insulin leaks back to the skin surface
• Reduces skin irritation
• And prevents many pull outs

88
Tape The Tubing
14

• This helps prevent
• Tugging
• Irritation
• Bleeding

89
ExamplesLack Of Anchoring Of Sets
14
A review of dozens of pictures of infusion sets
online and pump manuals finds that anchoring of
the infusion line with tape is rarely recommended
or practiced.
No tape!
90
Review Infusion Set Monitor
14

• Many pump wearers experience random erratic
  readings until they change to a different
  infusion set or start to anchor their infusion
  lines with tape to stop line tugging.
• However, insulin pumps offer no mechanism for
  clinicians or pump users to detect who may be
  having problems with their infusion sets.

91
ToolInfusion Set Monitor
14

• Insulin pumps with direct BG entry can identify
  those who may be having intermittent loss of
  glucose control secondary to infusion set
  failure. The pump
• Shows the average time and variation in time of
  use between reservoir loads or use of the priming
  function.
• Shows average BGs for each full or partial 12 or
  24 hour time interval following set changes
  (indicated by the prime function) over a various
  number of set changes or as soon as statistical
  significance is reached.

Adjustable setting in pump/controller