1 / 78

A Patient Safety Initiative For Insulin Pumps

Proposals for improving insulin pump use and medical outcomes through guidelines and practices. Feedback and suggestions welcome.

longenecker
Télécharger la présentation

A Patient Safety Initiative For Insulin Pumps

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. A Patient Safety Initiative For Insulin Pumps Standards and recommended practices to improve insulin pump use and medical outcomes These proposals are not final. They will undergo a single editorial review before being distributed for wider signatures. Your editorial comments are needed at this time. All suggestions you have for improvements, additions, or deletions are welcomed and will be attributed. Send comments to: John Walsh, PA, CDE at jwalsh@diabetesnet.com or call (619) 497-0900

  2. Over 500,000 insulin pumps are in use around the world, yet no formal guidelines regarding pump settings, safety features, and use have been adopted by the diabetes clinical community and pump manufacturing industry. The slides present a preliminary set of guidelines for standards and recommended pump practices. Most of these cannot be integrated into current insulin pumps, but we recommend that they be seriously considered for all new pump models. Introduction

  3. John Walsh, PA, CDE Ruth Roberts, MA Gary Scheiner, MS, CDE Timothy Bailey, MD, FACE Steve Edelman, MD Your name Etc These Standards And Recommended Practices Are Supported By: * Any reservations you have about a standard will be modified or noted

  4. 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.

  5. Why Insulin Pump Guidelines Are Needed These standards and recommended practices are designed to improve: • Consistency of pump settings between pump manufacturers • Accuracy and safety of carb and correction factors • Safety of DIA defaults and increments • Consistency in the handling of BOB • Improved monitoring for hypoglycemia & hyperglycemia • Faster notification that use of correction boluses is excessive • Faster identification of control problems related to infusion sets • Consistency in the presentation of data in history screens

  6. Benefits Pump users and clinicians will be able to quickly make sound clinical decisions when changing between pumps. Clinicians will be able to make better decisions when managing a variety of pumps Adjunctive medical and accessory personnel (ER, surgical, school nurses, etc.) can more easily interact and be trained in pump use

  7. ReviewWhat % of The TDD Changes The BG? To understand some slides that follow, it helps to know how much of a change in the TDD creates a significant change in the glucose level. Using a conservative 2000 Rule to set the correction factor, 1.25% of anyone’s TDD is sufficient to change the glucose by 25 mg/dl when given as a single dose. About a 5% change in the TDD is equivalent to a 25 mg/dl reduction in the glucose through the day. A change in the carb factor of 5 to 6% (about 2.5% to 3% of the TDD) is sufficient to change the glucose by about 20 mg/dl per meal.

  8. # Topic Carb Factor Increments Correction Factor Increments Personal Carb Factors Personal Corr Factors DIA Settings DIA Time Increments Severe/Frequent Hypoglycemia Overview These slides are numbered by topic for easy reference. # Topic 8. Severe/Frequent Hyperglycemia 9. Correction Bolus Alert 10. Insulin Stacking Alert 11. Automatic BG Entry 12. BOB Handling 13. Linear And Curvilinear DIA 14. Infusion Sets

  9. Carb Factor (CarbF) Increments 1 Issue: Safety is compromised for many pump users because current carb factors lack the precision required to avoid excess hyperglycemia and hypoglycemia. Current carb factor increments are too large to provide accurate carb boluses, especially for those who use smaller carb factors.

  10. ExampleCarb Factor Increments 1 • Most pumps offer 1 gram per unit as their smallest CarbF increment. This increment becomes relatively large for CarbFs below 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 the a carb factor larger than 5 or 6% would be expected to create more than a 20 mg/dl shift in the glucose following each meal.

  11. ExampleImpact On BG From CarbF Adjustments 1 This table shows the average additional fall in glucose after each meal of the day when a carb factor is reduced from 10 grams per unit to 9 grams per unit (for appropriate weight & TDD), and from 5 gr per unit to 4 gr per unit. * Calculated as avg. carbs/day – avg. carbs/day X 1 X 2000 new carb factor old carb factor 3 TDD

  12. ReviewMedian Carb Factor 1 In unpublished data from the Cozmo Data Analysis Study: • The median (middle) carb factor was 11.2 g/u • Almost all pumpers used carb factors below 20 g/u • 40% or more use carb factors of 10 g/u.

  13. 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%.

  14. 1 Standard For: Carb Factor Increments We recommend that carb factor increments be smaller than 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. We recommend minimum carb factor increments of: 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

  15. 2 Standard For: Correction Factor Increments For similar reasons, we also recommend that correction factor increments be smaller than 5% of the next larger whole number in order that a single step adjustment causes subsequent correction boluses to change by no more than 5% from previous doses. We recommend minimum correction factor increments of: 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

  16. Personal Carb Factors 3 Issue: Many carb factors used in insulin pumps today are poorly tuned to the user’s need. When a carb factor does not match an individual’s need, this will significantly magnify other sources of error in carb bolus calculations.

  17. Review Carb Factors In Use 1 3 Avg. carb factors* for 468 consecutive Cozmo insulin pump downloads (>126,000 boluses) are shown in blue Note that they are NOT bell-shaped or physiologic People prefer “magic” numbers – 7, 10, 15, and 20 g/unit – for their carb factors * Determined directly from grams of carb divided by carb bolus units for each carb bolus 10 7 115 20 1

  18. ReviewCarb Factors In Use 1 3 MANY magic carb factors, shown in blue, are inaccurate. A more normal or physiologic distribution is shown in green Use of magic numbers creates major, consistent bolus errors that magnify other sources for error 10 7 115 20 1

  19. 3 Recommended Practice For: Personal Carb Factors To encourage use of accurate carb factors, we request that research studies be undertaken to determine what range of carb factor rule numbers (CarbF x TDD) provide optimal glucose results (lower eAG and a minimum of hypoglycemia). These rule numbers may vary for various TDD ranges and for the percentage of carbs in the diet. Research results will be published as a reference for clinicians.

  20. 3 Recommended Practice For: Personal Carb Factors To ensure that carb factor selection is being individual-ized, we ask that insulin pump companies measure and publish each year carb factors from a sufficient number of random downloads of pumps which use carb factors. We recommend that tools be adopted to improve the accuracy of carb factors, specifically automated carb factor recommendations based on the user’s TDD and percentage of carbs in their diet. 5. We recommend that efforts be undertaken to automate carb factor testing.

  21. ExampleSample Carb Factor Setting Guide 3 To assist users in setting accurate CarbFs, insulin pumps should allow the user to compare their current CarbF to a range of best practices settings derived from CarbF Rule Numbers* gained from pumps with similar TDDs of users whose avg. BGs are < 180 mg/dl without frequent or severe hypoglycemia: * Carb Factor Rule Numbers = carb factor x TDD ** Optimal ranges would be determined from research studies of best practices

  22. Personal Correction Factors 4 Issue: Many correction factors used in insulin pumps today are poorly tuned to the user’s need. When a correction factor does not match an individual’s need, this will significantly magnify other sources of error in correction bolus calculations.

  23. 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 Users or clinicians appear to frequently select “magic” numbers for correction factors. 10 7 115 20 1

  24. 4 Recommended Practice For: Personal Correction Factors To encourage use of accurate correction factors, we request that research studies be undertaken to determine what range of correction factor rule numbers (CorrF x TDD) provide optimal glucose results (lower eAG and a minimum of hypoglycemia). Rule numbers may vary for various TDD ranges. Research results will be published as a reference for clinicians. To ensure that correction factor selection is being individualized, we request that insulin pump companies measure and publish each year correction factors from a sufficient number of random downloads of pumps which use correction factors for corrections.

  25. 4 Recommended Practice For: Personal Correction Factors 3. We recommend that tools be adopted to improve the accuracy of correction factors, specifically automated correction factor recommendations based on the user’s TDD. 4. We recommend that efforts be undertaken to automate correction factor testing.

  26. ExampleSample Correction Factor Setting Guide 4 To assist users in setting accurate CorrFs, insulin pumps should allow the user to compare their current CorrF to a range of best practices settings derived from CorrF Rule Numbers* derived from pumps with similar TDDs of users whose avg. BGs are < 180 mg/dl without frequent or severe hypoglycemia: * Correction Factor Rule Numbers = corr factor x TDD ** Optimal ranges would be determined from research studies of best practices

  27. DIA Settings 5 Issue: Duration of insulin action measures the glucose-lowering activity of a carb or correction bolus over time. In research studies, inter-individual variation in the pharmaco-dynamic time for rapid insulins is generally about 25%. However, the DIA times recommended by clinicians vary widely from 2 to 6 hours or more.

  28. ReviewHow Long Do Boluses Lower The BG? 5 • One insulin manufacturer states their insulin’s pharmacodynamics is 3 to 5 hours 10, but numerous studies show rapid insulin lowers 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. 10 Novolog product labeling information, October 21, 2005. 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; 22:1501-1506. 13 L Heinemann, et al: Time-action profile of the insulin analogue B28Asp. Diabetic Med 1996;13:683-684.

  29. ReviewShort DIAs Hide Bolus Insulin Activity 5 A short DIA time hides true BOB level and its glucose-lowering activity. This: • Leads to “unexplained” lows • Leads to incorrect adjustments in basal rates, carb factors, and correction factors • Causes user to start ignoring their “smart” pump’s advice Inappropriately long DIAs overestimate bolus insulin activity. DIA should be based on an insulin’s real action time. Do NOT modify the DIA time to fix a control problem

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

  31. 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) Regular Apidra product handout, Rev. April 2004a

  32. 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. 1993;42(Suppl. 1):54A

  33. 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 the pharmacodynamics of insulin tends to underestimate insulin’s true duration of action. See the next slide.

  34. ReviewPharmacodynamics Underestimates DIA And Overestimates Impact Of Bolus Size 5 • To measure pharmaco-dynamics, glucose clamp studies are done in healthy individuals (0.05 to 0.3 u/kg) • Because there is no basal suppression, this injected insulin ALSO SUPPRESSES normal basal release from the pancreas (grey area in figure) • Basal suppression also makes smaller boluses appear to have a shorter DIA

  35. ReviewPharmacodynamic Time Does Not Equal DIA 5 After accounting for the lack of basal suppression, • True DIA times become longer than the pharmacodynamic times derived from typical research • At least some of the apparent variation in DIA related to bolus size may also disappear • Some of the apparent inter-individual variation in pharmacodynamics may also disappear

  36. 5 Standards For:Duration Of Insulin Action We recommend that a panel of experts in insulin action review existing pharmacodynamic studies, consider differences between pharmacodynamics and the DIA time used in pumps, and recommend guidelines for acceptable ranges for DIA times in pumps for children and adults. Default DIA times in current pumps vary widely between 3 and 6 hours. We recommend that guidelines be set for consistent and accurate default times in pumps that use different methods to measure DIA.

  37. DIA Time Increments 6 Issue: Current DIA time increments vary from 15 minutes to 1 hour in different pumps • When a DIA time is changed in a pump, a larger time increment, such as 1 hr, can introduce an excessive change 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 25%.

  38. ReviewGlucose Infusion Rate (GIR) Studies 6 Most GIR studies suggest that pharmacodynamic action of insulin varies only about 25% 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 only 1 hr DIA increments would enable the user to select only 1 or 2 setting within this physiologic range, while a 30 min increment would allow only 2 or 3 choices that are close to a physiologic range.

  39. 6 Standard For: DIA Time Increments For safe and accurate estimates of residual BOB, we recommend that DIA time increments be no greater than 15 minutes.

  40. Frequent/Severe Hypoglycemia Alert 7 Issue: Although most current insulin pumps contain sufficient data to do so, pumps (and glucose monitors) do not warn users when the user is experiencing patterns of excessively frequent or severe hypoglycemia.

  41. 7 Recommended Practice For:Hypoglycemia Alert We recommend that insulin pumps which store glucose and insulin dosing data have this data easily accessible on the pump and that the user be alerted when they experience frequent* or severe* hypoglycemia. We recommend that specific guidance be provided regarding likely causes based on the pattern of hypoglycemia and the user’s current settings. * Adjustable setting in pump/controller

  42. ExamplePump Screen Hypoglycemia Display 7 * Adjustable setting in pump/controller

  43. Frequent/Severe Hyperglycemia 8 Issue: Although most current insulin pumps contain sufficient data to do so, pumps (and glucose monitors) do not warn users when the user is experiencing patterns of frequent or severe hyperglycemia.

  44. 8 Recommended Practice For:Hyperglycemia Alert We recommend that insulin pumps which store glucose and insulin dosing data have this data easily accessible on the pump and that the user be alerted when they experience frequent* or severe* hyperglycemia. We also recommend that specific guidance be provided regarding likely causes based on the pattern of hyperglycemia and the user’s current settings. * Adjustable setting in pump/controller

  45. ExamplePump Screen Hyperglycemia Display 8 * Adjustable setting in pump/controller

  46. Correction Bolus Alert 9 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, this information is often not shown and no alert is given regarding the excess.

  47. 9 Recommended Practice For:Correction Bolus Alert We recommend that insulin pump companies show in an easily available history what percentage of the TDD is used for correction boluses. We recommend that the pump wearer be able to request that the pump alert them when they are using more than 8% (adjustable) of their TDD for correction bolus doses over a 4 day period (adjustable). We recommend that once an excess in correction bolus is identified, that the user be provided with guidelines in how to safely distribute any excess in correction boluses into carb boluses or basal rates.

  48. Insulin Stacking Alert 10 Issue: Pump users often bolus for carbs without checking their glucose first. Without a glucose reading, the pump cannot account for BOB, and the bolus is not appropriately adjusted for the BOB or the current BG. However, data in the pump is available at the time the bolus is given whether the BOB is sufficiently large to substantially change a bolus dose. The pump can alert the user to this otherwise unseen insulin stacking.

  49. 10 Recommended Practice For:Insulin Stacking Alert We recommend that insulin pumps alert* the wearer when there is sufficient insulin stacking to introduce a significant error in a current bolus (such as BOB greater than 1.25%* of TDD). The alert would be on by default once a DIA time is selected to measure BOB, but may be turned off if the user desires. * Adjustable setting in pump/controller for an expected mg/dl drop in glucose with visible, audio, or vibratory output.

  50. ExampleInsulin Stacking or BOB Alert 10 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

More Related