Insulin Pump Therapy Celia Levesque RN, MSN, CNS-BC, NP-C, CDE, BC-ADM
clevesqu@mdanderson.org
Objectives:
• Calculate initial insulin pump doses • Adjust insulin pump settings References
• Bolderman, K. M. (2012). Putting your patients on the pump: Initiation and maintenance guidelines (2nd ed). Alexandria, VA: American Diabetes Association.
• Grunberger, G, Abelseth, J., Bailey, T, et. al. Consensus state by the American Association of Clinical Endocrinologist/American College of Endocrinology Insulin Pump Management task force. Endocrine Practice. 2014;20(5):463-489.
• Kaufman, F. R. (2012). Insulin pumps and continuous glucose monitoring: A user’s guide to effective diabetes management. Alexandria, VA: American Diabetes Association.
• Walsh, J. & Roberts, R. (2012). Pumping insulin: Everything you need to succeed on an insulin pump (5th ed). San Diego, CA: Torrey Pines Press.
Calculating Starting Pump TDD
• Method 1 : Pre-pump TDD x 0.75 • Method 2: Weight: kg x 0.5 or lb. x 0.23 Clinical considerations on pump TDD
• Average values from methods 1 & 2 • Frequent hypoglycemia: start at lower dose
• Hyperglycemia, éHbA1c, pregnancy: start higher dose Basal Rate
• Pump TDD x 0.5 ÷ 24 hrs. • Start with one basal rate
• Adjust according to BG trends over 2-3 days • Adjust to maintain stability in fasting state
• Add additional basal rates according to diurnal variations Carbohydrate Ratio
• 450 ÷ TDD
• Adjust based on low-fat meals w known CHO • 2 hr. PP rise ~ 60 mg/dL
• Adjust CR in 10-20% increments • Alternate methods:
6 x wt. in kg÷ TDD or 2.8 x wt. in lb. ÷ TDD Fixed Meal Bolus = TDD x 0.5 ÷ 3 equal meals Continue existing CR from MDI regimen
Sensitivity/Correction Factor
• 1700 ÷ Pump TDD
• To assess SF, check BG 2 hrs. after correction BG should be 30 mg/dL of target
Make adjustments in 10-20% increments if 2 hr. PP are consistently above or below target Example 1: Calculate the Initial Doses
Ms. Washington is a 25 year-old 60 kg female with type 1 diabetes since age 15. • Previous insulin doses:
• Basal insulin 10 units q am/pm • Rapid-acting insulin 7 units ac • Calculate
• Single basal rate • I:C ratio • Sensitivity factor Answer:
Ms. Washington was previously taking 41 units per day before starting on the pump. Pump total dose based on method 1
o Method 1 : Pre-pump TDD x 0.75 41 x 0.75 = 30.75
Pump total dose based on method 2
o Method 2: Weight: kg x 0.5 or lb. x 0.2 60 kg x 0.5 = 30
Pump total dose based on the average of method 1 & 2 o 30.75 + 30 ÷ 2 = 30.375
Single basal rate based on method 1 o Pump TDD x 0.5 ÷ 24 hrs o 30.75 x 0.5 ÷ 24 hrs
o 30.75 x 0.5 = 15.375 ÷ 24 hrs = 0.64. You can round to 0.625 or 0.65 units per hour Single basal rate based on method 2
o Pump TDD x 0.5 ÷ 24 hrs o 30 x 0.5 ÷ 24 hrs
o 30 x 0.5 = 15 ÷ 24 hrs = 0.625
Single basal rate based on average of method 1 & 2 o Pump TDD x 0.5 ÷ 24 hrs
o 30.375 x 0.5 ÷ 24 hrs
o 30.375 x 0.5 = 15.18 ÷ 24 hrs = 0.63. You can round to 0.625 or 0.65 units per hour Insulin to carbohydrate ratio
o 450 ÷ TDD (prepump)
450 ÷ 41 = 10.97. Round to 11. 1 unit per 11 grams of carbohydrate Sensitivity factor based on method 1
o 1700 ÷ Pump TDD
o 1700 ÷ 30.75 = 55.28. Round to 55 Sensitivity factor based on method 2
o 1700 ÷ Pump TDD
Example 2: Calculate the Initial Doses
Mr. Simmons is a 32 year-old 95 kg male with a recent total pancreatectomy • Previous insulin doses:
• Basal insulin 25 units q pm
• Rapid-acting insulin 1 unit per 9 gm CHO + SF 35, T 150 mg/dL • Calculate
• Single basal rate • I:C ratio • Sensitivity factor Answer:
Since the example does not exactly say how much the patient actually takes from day to day, you would, in reality, look at their logbook and take an average of their total daily dose for the past week. For this example, assume that this patient takes 50% basal and 50% bolus so base the formulas on a total daily dose of 50 units.
Pump total dose based on method 1 (based on pre pump dose) o Method 1 : Pre-pump TDD x 0.75
50 x 0.75 = 37.5
Pump total dose based on method 2 (based on weight) o Method 2: Weight: kg x 0.5 or lb. x 0.2
95 kg x 0.5 = 47.5
Pump total dose based on the average of method 1 & 2 o 37.5 + 47.5 ÷ 2 = 42.5
Single basal rate based on method 1 o Pump TDD x 0.5 ÷ 24 hrs o 37.5 x 0.5 ÷ 24 hrs
o 37.5 x 0.5 = 18.75 ÷ 24 hrs = 0.78. You can round to 0.775 or 0.8 units per hour Single basal rate based on method 2
o Pump TDD x 0.5 ÷ 24 hrs o 47.5 x 0.5 ÷ 24 hrs
o 47.5 x 0.5 = 23.75 ÷ 24 hrs = 0.98. You can round to 1.0 units per hour Single basal rate based on average of method 1 & 2
o Pump TDD x 0.5 ÷ 24 hrs o 42.5 x 0.5 ÷ 24 hrs
o 42.5 x 0.5 = 21.25 ÷ 24 hrs = 0.88. You can round to 0.875 or 0.9 units per hour Insulin to carbohydrate ratio
o 450 ÷ TDD (prepump)
450 ÷ 50 = 9
1 unit per 9 grams of carbohydrate Sensitivity factor based on method 1
o 1700 ÷ Pump TDD
Mr. Henderson is a 58 yo male with T2DM. He weighs 118 kg • Home insulin doses:
• Basal insulin: 60 units q pm • Rapid-acting insulin: 15 units q ac • Calculate
• Single basal rate • I:C ratio • Sensitivity factor
Notice that this patient is taking more basal insulin than bolus insulin. This is very common. Often, patients who are sedentary or older need more basal than bolus. Continue to use the same pump calculations based on the previous total daily dose to start the patient on the pump and then adjust as needed. Also notice that the higher the previous total daily insulin dose, the greater the variance in the pump calculation. Use your clinical judgment in choosing which method you should use.
Pump total dose based on method 1 o Method 1 : Pre-pump TDD x 0.75
105 x 0.75 = 78.75 Pump total dose based on method 2
o Method 2: Weight: kg x 0.5 or lb. x 0.2 118 kg x 0.5 = 59
Pump total dose based on the average of method 1 & 2 o 78.75 + 59 ÷ 2 = 68.87
Single basal rate based on method 1 o Pump TDD x 0.5 ÷ 24 hrs o 78.75 x 0.5 ÷ 24 hrs
o 78.75 x 0.5 = 39.37 ÷ 24 hrs = 1.64. You can round to 1.625 or 1.65 or units per hour. Single basal rate based on method 2
o Pump TDD x 0.5 ÷ 24 hrs o 59 x 0.5 ÷ 24 hrs
o 59 x 0.5 = 29.5 ÷ 24 hrs = 1.22. You can round to 1.25 or 1.2 units per hour. Single basal rate based on average of method 1 & 2
o Pump TDD x 0.5 ÷ 24 hrs o 68.87 x 0.5 ÷ 24 hrs
o 68.87 x 0.5 = 34.43 ÷ 24 hrs = 1.43. You can round to 1.425 or 1.45 units per hour. Insulin to carbohydrate ratio
o 450 ÷ TDD (prepump)
450 ÷ 105 = 4.28
1 unit per 4 grams of carbohydrate Sensitivity factor based on method 1
o 1700 ÷ Pump TDD
o 1700 ÷ 78.75 = 21.58. Round to 22 Sensitivity factor based on method 2
o 1700 ÷ Pump TDD
o 1700 ÷ 59 = 28.81. Round to 29. Sensitivity factor based on average of method 1 & 2
o 1700 ÷ Pump TDD
Protocol for Pregnancy
Insulin Infusion Rate for T1DM: Total Basal Insulin Requirement for 24 hr.
Gestation Units x wt. in kg
Prepregnancy 0.3
First trimester 0.35
Second trimester 0.4
Third trimester 0.45
Term pregnancy > 38 weeks 0.5
Hourly Infusion Rate Changes Based on Time of Day (divide the total basal U by 24)
12-4 am 0.5 x calculated basal ÷ 24
4-10 am 1.5 x calculated basal ÷ 24
10 am – 6 pm 1 x calculated basal adjust based on stress and exercise during the time period
6 pm – 12 am 1 x calculated basal adjust based on stress and exercise during the time period
Meal-related Insulin Bolus
Gestation Units x wt. in kg (divide into thirds for a dose before each meal)
Prepregnancy 0.3
First trimester 0.35
Second trimester 0.4
Third trimester 0.45
Term pregnancy > 38 weeks 0.5
After second trimester, in case of dislodgment at infusion site:
• Dose of NPH 0.1 x wt. in kg before bed, then a lower early morning insulin infusion rate • Alternative: use metal needle infusion set
Testing Pump Settings
• Bolderman, K. M. (2012). Putting your patients on the pump: Initiation and maintenance guidelines (2nd ed). Alexandria, VA: American Diabetes Association.
• Walsh, J. & Roberts, R. (2012). Pumping insulin: Everything you need to succeed on an insulin pump (5th ed). San Diego, CA: Torrey Pines Press.
• Kaufman, F. R. (2012). Insulin pumps and continuous glucose monitoring: A user’s guide to effective diabetes management. Alexandria, VA: American Diabetes Association.
Do not test if all of the rules can’t be followed
• Do not disconnect from the pump, stop delivery, or run a temporary basal rate, or deliver an extended bolus • Do not perform more than one test per day
• Perform each test several times to ID trend • Do not perform basal testing during pregnancy • Do not eat food. Only drink calorie free fluids • Do not consume caffeine
• Do not consume alcohol within 24 hrs. before • Do not test during illness/periods of stress • Do not test if all of the rules can’t be followed • Do not test during unusual activity
• Do not test following strenuous exercise/activity • Do not test within 12 hours of hypoglycemia • Stop test if hypoglycemia occurs
Basal Testing: Prepare
• Select a basal period to test
• Plan to skip a meal during the test period
• Wait 4-5 hours after eating the last meal or snack before the test begins
• Check pump to make sure there is no active insulin on board at the start of the test Overnight Basal Test
• Eat early dinner
• Monitor BG hs, q 3 hrs., and waking • Ends at breakfast
• Morning
• Skip breakfast • Monitor BG q 1-2 hrs. • Ends at lunch Morning Basal Test
• Skip breakfast • Monitor BG q 1-2 hrs. • Ends at lunch Afternoon Basal Test
• Skip lunch
• Monitor BG q 1-2 hrs. • Ends at dinner Evening Basal Test
• Skip dinner
• Monitor BG q 1-2 hrs. • Ends at bedtime
Basal Testing
• Monitor BG at start of the test • Do not start if BG < 90 or > 150 mg/dL • Stop the test if BG < 70 or > 250 mg/dL • Daytime tests: check BG q 1-2 hrs.
• Overnight test: check hs BG, 2 am, and waking • Repeat testing 2-3 times to ID trend
• Adjust basal rate if fluctuations of > 30 mg/dL • Change by 5-10%
• Make changes before BG starts to trend up or down. It may take 2.5 to 4 hrs. for basal to change • Assess effectiveness of the basal change
Overnight Basal Test
Morning Basal Test
Testing CHO Ratio
• Eat a known amount of CHO between 45-70 g • Eat a balance of CHO, protein, fat
• Wait 4-5 hours after last food consumption to start the test • Make sure no insulin on board at start of test
• Monitor BG at start of test and q 1 hr. for 5 hrs. • Do not start test if BG < 90 or > 150 mg/dL • Eat meal 15 minutes after bolus
• Do not eat during test • Stop test if BG < 70 or > 250
• BG should be within 30 mg/dL from starting BG • Repeat test several times
• Adjust CHO ratio as needed CHO Bolus Test 1
Testing Correction Factor • Start test when
BG is > 200 mg/dL
No food for 4 hours before start of test No bolus for 4 hours before start of test • Monitor BG at start of test, and q 1 hr. x 5 hrs. • Do not eat or bolus during test
• Stop test if BG < 70 or > 250 mg/dL and treat appropriately • End BG should be within 30 mg/dL of target
• Repeat test several times • Adjust as needed Correction Factor Test
Pump Education • Establish goals • When to check BG • Learn CHO counting
• Learn to calculate insulin to CHO ratio • Learn correction/sensitivity factor • Correctly treat hyper and hypoglycemia • Prevention of DKA
• Choose infusion set • Pump Education
• Manage day to day issues: Illness Menstrual cycle Exercise Travel Stress Pump disconnection Counting CHO: Reading Labels
1. Look at serving size
2. Decide how many servings will be consumed 3. Multiply the number of servings by the total gm
CHO
Smart Phone Apps/Computer • Calorie King • My Net Diary • Spark People • Go Meals • Fooducate • dLife diabetes • WaveSense • My Glucose Buddy
Total Available Glucose: Original 100% of carbohydrate grams 50% of protein grams 10% of fat grams Total Available Glucose: Joslin:
According to Joslin: original system may overestimate the amount insulin needed for high-protein, low-fat meal and underestimate requirements for high fat meal
Total Available Glucose: Washington Medical Center • Carbohydrate: 100%
• Protein: 58% affects BG for 3-6 hrs. • Fat: 10% affects BG for 8-10 hrs.
Food Serving size GM CHO TAG
Meat 1 oz. 0 4
Milk 1 cup 12 17
Casserole 1 cup 30 38
Cheese pizza, thin ¼ of 10” 30 34
Chili with beans 1 cup 30 38
Bean soup 1 cup 20 24
Hormel Cheezy Mac ‘n Franks
Serving Size 1 container 7.5 ounces
Calories per serving 280
Total fat 18 grams
Total carbohydrate 20 grams
Fiber 1 gram
Sugar alcohol 0
Protein 10 grams
Raisin Bran
Serving Size 1 cup
Calories per serving 200
Total fat 1.5 grams
Total carbohydrate 47 grams
Sugar Free Dark Chocolates
Serving Size 5 pieces
Calories per serving 190
Total fat 15 grams
Total carbohydrate 23 grams
Fiber 3 grams
Sugar alcohol 18 grams
Protein 2 grams
Pizza Hut Thin ‘n Crispy Cheese Pizza 1 slice from 12” Pizza
Serving Size 1 slice
Calories per serving 190
Total fat 8 grams
Total carbohydrate 22 grams
Fiber 1 gram
Sugar alcohol 0
Protein 8 grams
Chick-fil-A Nuggets
Serving Size 8 nuggets
Calories per serving 270
Total fat 13 grams
Total carbohydrate 10 grams
Fiber 1
Sugar alcohol 0
Exercise
• Most studies show little impact on A1c for T1DM • Benefits of exercise same as non DM
• If exercise performed within 90 min of a meal, may reduce mealtime bolus Metabolic Response to Light and Moderate Exercise
Normal
• Insulin level decreases • Glucagon increases
• Free fatty acid mobilization increases
• Restriction of glucose by non-exercising skeletal muscle T1DM
• Insulin level fails to change at the onset of exercise
• Insulin excess: muscle glucose uptake exceeds liver glucose production
• Insulin deficiency: liver glucose production exceeds muscle uptake; FFA release and ketone body formation increase • Adequate insulin: liver glucose output matches muscle glucose uptake
Exercise and Pumps
Bolus Reduction if Exercise within 90 minutes after a meal Short duration
20-40 minutes Moderate duration 40-60 minutes Long duration > 60 minutes
Low intensity - 10% - 20% - 30%
Moderate intensity - 25% - 33% - 50%
High intensity - 33% - 50% - 67%
CHO Replacement in grams per 30 min of exercise
Weight 50 lb.
23 kg 100 lb. 45 kg 150 lb. 68 kg 200 lb. 91 kg 250 lb. 114 kg
Light activity 3 5 8 10 12
Moderate 5 8 10 12 15
Intense 8 12 18 24 30
Basal Adjustment for Prolonged Activity • Exercising < 90 minutes: do not change basal • Exercise > 2 hours
Starting point: decrease basal by 50% If more intense activity: 70-80% reduction Start reduction 1-2 hrs. before prolonged exercise
Resume full basal rate prior to stopping prolonged exercise • Delayed hypoglycemia may occur after prolonged/intense activity Exercise Induced Hyperglycemia
• Weight lifting
Troubleshooting Hyperglycemia • Insulin
Loss of potency Wrong insulin in pump • Infusion set
Bent catheter Air in tubing Infusion site problem • Insulin pump
Programming error Pump malfunction • Behavior
Missed bolus Bloused after eating Did not correct Miscount CHO
BG > 250 mg/d: take correction bolus via pump. Recheck BG in 1 hour. If BG not decreasing then check ketones and follow guidelines: Negative Ketones
• Inject insulin using a syringe: the dose according to the correction factor • Drink 8 ounces of sugar-free fluids every 30 minutes
• Recheck BG in 1 hour
• If the BG does not decrease, follow the steps in the positive ketones column Positive Ketones
• Using a new vial of insulin, inject insulin with a syringe: the dose according to the correction factor • Change the entire infusion set/reservoir using the new insulin
• Recheck BG in 1 hr. • Drink sugar-free fluids
• If BG does not decrease, contact healthcare provider/go to ER Supplies Needed • Insulin • Syringes • Pump supplies • Monitoring supplies • Hypoglycemia treatment • Ketone testing: urine/blood • DM identification
• Glucagon Beta-hydroxybutyrate
• Precision Xtra: 0.6 – 1.5 = call MD, > 1.5 = go to ER • NovaMax: 0.6 – 1.5 = call MD, > 1.5 = go to ER Hypoglycemia
• 20% of T1DM will die from hypoglycemia
• 40% of T1DM will have severe hypo if duration of > 15 years
• Annual rate of severe hypoglycemia requiring emergency medical services: 7.1% • Mortality rate 1 year after severe hypoglycemia T1 & T2 combined = 17% BG< 70 mg/dl: DM vs. Non DM
• No Diabetes
Insulin levels drop Glucagon secreted Epinephrine release
• T1DM or low C-Peptide Insulin levels high Glucagon not secreted Epinephrine release Norepinepherine Cortisol release Growth hormone Neurotransmitters Severe Hypoglycemia Treatment
• Causes glycogen to be converted into glucose • 1 kit raises BG ~ 50 mg/dl
• 1 Kit has 1 mg • Given SC, IM, or IV • 1 mg for child > 4 • ½ mg for child < 4 • Sites same as insulin • Push needle in all way Mini Dose Glucagon
• Pt unable to swallow CHO but is awake & alert with BG < 80 mg • 2 “units” for 1 yo
• 1 “unit” per year of age for 2 years & older • Max 15 “units”
• If not above 80 mg/dL in 30 min, double the dose (max 30) Special Situations • Illness • Menstrual cycle • Sex • Surgery • Steroids • Gastroparesis • Kids/Teens • Pregnancy Illness
• Frequent BG and ketone testing • Need basal to prevent DKA
• Do not reduce basal unless hypoglycemia
• Basal rates may need to be increased for fever, infection, surgical stress, etc. • Use hyperglycemia protocol as previous outlined
• If prolonged fasting: sensitivity factor may need to be changed • Increase noncaloric fluids
• Need some CHO to prevent ketosis
• If can’t eat solid food: may substitute with liquid CHO • Teach pt. to call if:
Fever > 100
Nausea, vomiting, diarrhea > 4 hrs.
Surgery/Procedure • What type of surgery? • How long is the surgery? • What time will the surgery start? • How long will the patient fast?
• What kind of diet will the patient have after surgery? • Will the patient be receiving IV dextrose?
• Will the patient be receiving steroid? • What type of anesthesia?
• Can the patient skip a meal without hypoglycemia? • Does the patient have a history of severe hypoglycemia? • Does the patient have hypoglycemia unawareness? General Anesthesia
• Neuroendocrine stress response Epinephrine Glucagon Cortisol Growth hormone • Inflammatory cytokines interleukin-6
tumor necrosis factor-alpha
Metabolic Abnormalities from Surgery/Anesthesia • Insulin resistance
• Decreased peripheral glucose utilization • Impaired insulin secretion
• Increased lipolysis and protein catabolism • Hyperglycemia
• In some cases: ketosis
• General anesthesia is associated with larger metabolic abnormalities as compared to epidural anesthesia Glycemic Goals for Surgery
• Avoidance of marked hyperglycemia • Avoidance of hypoglycemia
• Maintenance of fluid and electrolyte balance • Prevention of ketoacidosis
Options:
• Take pump off and replace basal insulin: 1 injection of basal prior to surgery ½ dose prior to surgery, ½ dose 12 hrs. later
Patient given corrections for hyperglycemia using Regular or Rapid-acting analog insulin • Leave pump on at full basal rate
Patient given corrections for hyperglycemia using Regular or Rapid-acting analog insulin • Leave pump on at reduced basal rate
Steroids
Steroid Equivalent Onset Duration
Betamethasone 20 0.6 mg Rapid Cortisone 1 25 mg Slow 30-36 h Dexamethasone 20 20-30 x > than HC 5-7 x > Prednisone 0.75 mg Rapid 72 hours
HC acetate 1 20 mg Slow Long
HC sodium phosphate 1 20 mg Rapid Short
HC sodium succinate 1 20 mg Rapid Short
MP 5 4 mg Rapid 30-36 h
Prednisolone 4 5 mg Rapid 18-36 h
Prednisone 4 5 mg Rapid
Steroids
• Low dose steroids: less than equivalent of Dexamethasone 40 milligrams 40% basal
60% bolus
• High dose steroids: equivalent of Dexamethasone 40 milligrams or higher 25% basal
75% bolus Steroids
• Total initial insulin dose:
Low dose steroids: start at 0.6-0.8 units/kg High dose steroids: start at:
0.9 units/kg if on metformin 1.2 units/kg if not on metformin Travel
• If sedentary during the travel: may need temp increase in basal rate 10-20% • Bring 50% more supplies than usually needed for the time away
Spare pump if available
Hypoglycemia treatment including glucagon Extra insulin with syringes
Extra monitoring supplies including spare meter, lancing device, ketone testing products • Know where the nearest pharmacy, and medical care available
• Extra glasses if needed
• Pack all medical supplies in a carry on bag • Insulin stable for 28 days at room temperature • Protect insulin from extreme heat
• Low dose x-ray screening and total body scanners: contact pump manufacturer • Check with airline and TSA for any changes in rules
• When changing time zones:
Keep the pump clock the same at departure and then change it to the new time zone after arriving to the new destination If a large time zone change pump clock 2 hours towards the new destination daily until the correct time is achieved Gastroparesis
Kids & Pumps
• Pump therapy in kids requires commitment and motivation on the part of caregivers • Children require frequent dose changes
• Tend to need more bolus and less basal insulin compared to adults • Teens are usually insulin resistant
• Common problems
Missed boluses Bent catheters
CHO counting is an adult concept Not finishing meal after bolus given Unpredictable, impulsive, erratic activity Total daily dose in T1DM
Units / Kg / Day Patient
0.5 Conditioned athlete, honeymoon phase
0.6 Motivated exerciser, woman in 1st phase follicular cycle
0.7 Women in luteal phase or 1st trimester pregnancy, adjust with mildly ill with virus, child starting puberty
0.8 Women in 2nd trimester pregnancy, adult with severe infection
0.9 Women in 3rd trimester pregnancy, adult with bacterial infection
1.0 Women at term pregnancy, adult with severe bacterial infection or illness, child at peak puberty
1.5-2.0 Child at peak puberty who is ill
Pregnancy • Target BG:
Premeal: 60-99 mg/dL Post meal 1 hr.: < 130 mg/dL • Target HbA1c: < 6%
• If frequent hypoglycemia, severe hypoglycemia, or hypoglycemia unawareness: customize target BG • Evaluate control twice weekly and adjust
Pregnancy: BG > 200 • Check ketones
• Give insulin via syringe or insulin pen • Change infusion set
Labor and Delivery
• Follow the hospital protocol • Hourly blood glucose checks • BG goal 80-120 mg/dL
• For elective C-section: decrease basal rate by 30% 8 hours before delivery while NPO and if prone to hypoglycemia, reduce 50% • Active labor: reduce basal rate 30-50%