Insulin Pump Therapy Bruce W. Bode, MD and Sandra Weber, MD

Goals of Targeted Insulin Therapy (Intensive/Physiologic/Flexible) Maintain near-normal glycemia Avoid short-term crisis Minimize long-term complications Improve the quality of life Hours

4: :0012:0016:0020:0024:004:00 BreakfastLunchDinner Plasma insulin (U/ml) Plasma insulin ( µ U/ml) Time 8:00 Physiological Serum Insulin Secretion Profile

4:0016:0020:0024:004:00 BreakfastLunchDinner 8:00 12:008:00 Time Glargine Plasma insulin Basal/Bolus Treatment Program with Rapid-acting and Long-acting Analogs LisproLisproLispro AspartAspartAspart or

4:0016:0020:0024:004:00 BreakfastLunchDinner 8:00 12:008:00 Time Basal infusion Bolus Plasma insulin Variable Basal Rate: CSII Program

Metabolic Advantages with CSII Improved glycemic control Better pharmacokinetic delivery of insulin —Less hypoglycemia —Less insulin required Improved quality of life

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Pump Infusion Sets

Current Pump Therapy Indications Diagnosed with diabetes (even new-onset type 1 diabetes) Need to normalize blood glucose —A1C > 6.5% —Glycemic excursions —Hypoglycemia Need for flexible insulin program

Monitoring —A1C = (0.21 x BG per day) Recording 7.4 vs 7.8 Diet practiced —CHO: 7.2 —Fixed: 7.5 —WAG: 8.0 Insulin type (Aspart) CSII Factors Affecting A1C Bode et al. Diabetes 1999;48 Suppl 1:264 Bode et al. Diabetes Care 2002;25 439

Initial Adult Dosage: Calculations Starting doses Based on pre-pump total daily dose (TDD)  reduce TDD by 25% to 30% for pump TDD Calculated based on weight  0.24 x weight in lb (0.53 x weight in kg) Bode BW, et al. Diabetes. 1999;48(suppl 1):84. Bell D, Ovalle F. Endocr Pract. 2000;6: Crawford LM. Endocr Pract. 2000;6:

Normal —Preprandial: mg/dl —1 hr postprandial:<160 mg/dl Hypoglycemic unawareness —Preprandial: mg/dl Pregnant —Preprandial: mg/dl —1 hr postprandial:<120 mg/dl Individually set for each patient Target BG Ranges for CSII Fanelli CG et al., Diabetologia 1994, 37: Jovanovich L, AMJObGynec 1991, 164:

Initial Adult Dosage: Calculations Basal rate 45% to 50% of pump TDD Divide total basal by 24 hours to decide on hourly basal Start with only 1 basal rate See how it goes before adding basals

Basal Dose Adjustment Overnight Rule of 30: Check BG Bedtime 12 AM 3 AM 6AM Adjust overnight basal if readings vary > 30 mg/dl

Adults often need an increase in basal rate in the “Dawn” hours (4 am to 9 am) Children often need an increase in basal rate earlier starting at 10 pm to 2 am Basal Dose Adjustment Overnight

4:0016:0020:0024:004:00 BreakfastLunchDinner 8:00 12:008:00 Time Basal infusion Bolus Plasma insulin Variable Basal Rate: CSII Program

Basal Dose Adjustment Daytime Rule of 30: Check BG Before usual meal time Skip meal Every 2 hrs (for 6 hrs) Adjust daytime basal if readings vary > 30 mg/dl

Bolus Dose Calculations Meal (food) Bolus Method 1 Test BG before meal Give pre-determined insulin dose for pre-determined CHO content Test BG after meal Goal < 60 mg/dl rise post meal or < 160 mg/dl

Individually determined CIR = (2.8 x wgt in lbs) / TDD Anywhere from 5 to 25 g CHO is covered by 1 unit of insulin Estimating the Carbohydrate to Insulin Ratio (CIR) Davidson et al: Diabetes Tech & Therap. April 2003

Correction Bolus Must determine how much glucose is lowered by 1 U of rapid-acting insulin This number is known as the correction factor (CF) Use the 1700 rule to estimate the CF CF=1700 divided by TDD example: if TDD=36 U, then CF=1700/36=  50, meaning 1 U will lower the BG  50 mg/dL

Correction Bolus Formula Example: —Current BG:220 mg/dL —Ideal BG: 100 mg/dL —Glucose CF: 50 mg/dL Current BG - Ideal BG Glucose Correction Factor = 2.4 U

If A1C is Not to Goal SMBG frequency and recording Diet practiced —Do they know what they are eating? —Do they bolus for all food and snacks? Infusion site areas —Are they in areas of lipohypertrophy? Other factors: —Fear of low BG —Overtreatment of low BG Must look at:

Case Study # 1 GL, male, age 39 Type 1 X 8 years A1C= 7%; recent increase from 6% CSII basal rates: 12 am 1.0 u/h; 4:30 am 1.6 u/h; 11:30 am 1.0 u/h Insulin: carbohydrate ratio =1u : 10 grams Correction Factor: BG divided by 40 CGMS done to assist with improving overall glycemic control

Modal Day View

Cheese / Crackers 20 g; 3units 30 gm CHO; Heavy Exercise 80 CHO; 7u 2u; 57 g CHO Milk choc 15g; 8u Juice box; no insulin Ice Cream; 3 u 6u

Most common bolusing errors Under-estimation of carbohydrates consumed (CHO bolus) Over-correction of post-prandial elevations (CF bolus) — Remaining unused, active insulin — Stacking of boluses

Bolus: Source of Errors “Inability” to count carbs correctly — Lack of knowledge, skill — Lack of time — Too much work Incorrect use of SMBG number Incorrect math in calculation “WAG” estimations

The Major Problems ♦Up until now we have not taken the active insulin issue into consideration ♦The math involved with this has become too complicated, and it would be impossible to accurately calculate the active insulin without assistance

Smart Pumps

Monitor sends BG value to pump via radio waves : No transcribing error Enter carbohydrate intake into pump “Bolus Wizard” calculates suggested dose Paradigm Link ™ Paradigm 512 ™ ) ) ) ) ) ) ) ) ) ) ) ) ) Bolus Wizard Calculator : meter-entered

Insulin Activity Over Time Rapid Acting Regular Insulin Activity (GIR) Time (hrs) Insulin Pharmacodynamic Data Adapted from Henry R: Diabetes Care 1999

Rapid Acting Regular Time (hrs) Percent Remaining Adjusting for Active Insulin: How smart pumps do it

Wizard: On Carb Units: grams Carb Ratios: 10 BG Units: mg/dl Sensitivity: 50 BG Target: 100 Bolus Wizard Set Up Screen

For This System To Work ♦It is critical the target, basal doses, the correction doses, and the carbohydrate ratios are accurate ♦Understanding how to match carbohydrate amounts with insulin is critical

Do Smart Pumps Enable Others To Go To CSII? YES All patients with diabetes not at goal are candidates for Insulin Pump Therapy - Type 1 any age - Type 2 - Diabetes in Pregnancy

Summary Insulin pump therapy offers improved glucose control with less risk of hypoglycemia and an improvement in quality of life Appropriate candidate selection, training, and follow-up ensures safe and effective therapy

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