Adjusting Your Basal Rates On Insulin Pumps

Transcription

1 Adjusting Your Basal Rates On Insulin Pumps Now that you are on an insulin pump your basal insulin doses will still need to be adjusted just like when you received insulin injections. The reasons your insulin doses need adjustment include the following: as you enter the honeymoon phase shortly after diagnosis your insulin doses will decrease as you grow you will need more insulin to keep your blood glucose levels n control insulin requirements increase during your teenage years changes in your activity level illness special events such as birthdays, holidays, and vacations Before you make any adjustments to your insulin doses it is important to know what your target blood glucose range is. Research has shown that keeping your blood glucose levels in a range closer to normal significantly improves your overall health, decreases your risk for developing diabetes related complications, and improves blood glucose control. A study performed by the DirectNet Study Group found that approximately 95% of children without diabetes have fasting blood glucose levels between mg/dl and random blood glucose levels between mg/dl. Therefore, the Children s Mercy Diabetes Center has developed our own blood glucose guidelines based on these findings. The Children s Mercy Hospital Diabetes Center Recommended Blood Glucose Target Ranges (mg/dl) Age Suggested Blood Glucose Level 5 years or younger mg/dl 6 years and older mg/dl The American Diabetes Association recommends different blood glucose target ranges than our recommendations. You can find the ADA recommendations on their website: Once you know what your blood glucose target range is, you can start to look at your blood glucose patterns. The CMH diabetes team recommends looking at your blood glucose patterns for at least five days before any changes are made to your insulin doses. When looking at your blood glucose results it is important to look for blood glucose levels that are or below your target range and also what time of day the pattern occurs. You also want to consider other variables that can cause your blood glucose to increase or decrease.

2 Variables that can change the level of your blood glucose What makes blood glucose increase? Foods or drinks with carbohydrates Stress Illness (cold, fever, flu, or other infection) What makes blood glucose decrease? Exercise Insulin Honeymoon phase The best way to remember your blood glucose results and variables that may affect the results is to keep written records using a logbook or computer management system. On an insulin pump it is trickier to adjust your basal rates than to adjust your bolus insulin dose. As you know, the goal of your basal (background) insulin is to keep your blood glucose in target range during the overnight hours and also during the daytime should you decide to skip a meal. For example, a basal rate is set too high if you experience hypoglycemia when a meal is skipped. A basal rate is set too low if you have to use your correction bolus frequently to correct for hyperglycemia or if your blood glucose increases if you miss a meal. Basal rate testing is divided into 4 time periods: overnight, breakfast, lunch, and supper. Before you decide to test your basal rates there are some things you need to consider: The first time period you want to test is your overnight basal rate. This basal rate is most often incorrect. You want the same pattern in your blood glucose to occur at least two times before it is considered a pattern and adjustments are made. Your blood glucose level should always range before you perform a basal rate test. You should not exercise or eat high fat meals during the days that you are testing your basal rates. You should be confident of the carbohydrate gram amount and your bolus insulin dose in the meal that you eat prior to beginning a basal test. This meal should be low in fat. Basal rate testing should be stopped if your blood glucose level drops or rises your target range during the test. You should treat hypo or hyperglycemia as you normally would. Do not perform basal testing if you have experienced a severe low blood glucose that day. Do not test your basal rates if you are sick or under stress as your blood glucose levels typically elevate during these times. Basal rate testing should start 4-5 hours after your last bolus. While you are testing your basal rates, you need to check your blood glucose levels every 1-2 hours. During basal rate testing you want to keep an accurate and detailed log of your blood glucose values and the times the values occur. You should never evaluate all of your basal time periods on the same day. If your basal rates are set correctly, your blood glucose level should never change more than 40 points during the testing period.

3 Testing your overnight basal rate eat a low fat dinner eat no food afterwards begin basal test 4-5 hours after dinner as long as blood glucose (BG) is between mg/dl 4-5 hours after dinner bolus bedtime midnight 2:30 am when you wake in the morning Testing your breakfast basal rate Your basal rates are correct if your (BG) does not increase or decrease more than mg/dl during the basal test If your BG increases: your basal rate needs to be increased during this time period If your BG decreases: your basal rate needs to be decreased during this time period. check your BG when every 1-2 hours from the time evaluate your results as you wake up you wake up for 5 hours skip breakfast eat no food until lunch Testing your lunch-time basal rate check your BG before every 1-2 hours from the start evaluate your results as lunchtime the test for 5 hours skip lunch eat no food until dinner Testing your dinner-time basal rate check your BG before every 1-2 hours from the start of evaluate your results as dinnertime the test for 5 hours skip dinner eat a bedtime snack or late dinner at the end of the basal test time

4 End basal testing at any time if your blood glucose goes low or high. If your basal rate is too high, your blood glucose will drop during the basal rate test. If your basal rate is too low, your blood glucose will increase during the basal test. Guidelines for making adjustments to your basal rates: changes in your blood glucose of more than 40 mg/dl during the basal test indicate a need to adjust your basal rates. if your total daily dose of insulin is less than 20 units a day, increase or decrease your basal rate by 0.05 units/hour at a time. if your total daily dose of insulin is over 20 units a day, increase or decrease your basal rate by 0.10 units/hour at a time. you should increase or decrease your basal rate about 2 hours before you notice a pattern of high or low blood glucose readings. Only make one change at a time. In general, your different basal rates should not be drastically different. For example, if your highest basal rate is 0.9 units/hour, your would not expect to see your lowest basal rate less than 0.5 units/hour. In most circumstances your basal rate total makes up anywhere from 35-65% of your total daily insulin dose (TDD). Example: Sam s mom is testing his overnight basal rate. He has noticed a pattern that at 6 a.m. his blood glucose value increases more than 40 mg/dl from his bedtime, midnight, and 3 a.m. results. His current basal rate is 0.25 units/hr from midnight until 7 a.m. Sam s average total daily dose of insulin, TDD, is 15 units. What should his mom do? Day 1 9:00 p.m. 119 mg/dl Midnight 139 mg/dl 3:00 a.m. 126 mg/dl 6:00 a.m. 190 mg/dl Day 2 9:00 p.m. 101 mg/dl Midnight 140 mg/dl 3:00 a.m. 135 mg/dl 6:00 a.m. 210 mg/dl Answer: Sam s mom should increase his basal rate at 4:00 a.m. (2 hours before the pattern of high BG readings) by 0.05 units/hr (his TDD is less than 20 units). His new basal rates will be midnight 0.25 units/hr and at 4:00 a.m units/hr. She should recheck Sam s basal rates with the change in his insulin dose.

5 Example: Allison is checking her dinner-time basal rate. She has noticed a pattern of hypoglycemia around 11 p.m. Her current basal rates are as follows: midnight -1.0 units/hr; 5:00 a.m units/hr; 7:00 p.m units/hr. Allison s average total daily insulin dose is 43 units. What should she do? Day 1 5:00 p.m. 131 mg/dl 7:00 p.m. 106 mg/dl 9:00 p.m. 112 mg/dl 11:00 p.m. 66 mg/dl Day 2 5:00 p.m. 109 mg/dl 7:00 p.m. 100 mg/dl 9:00 p.m. 115 mg/dl 11:00 p.m. 63 mg/dl Answer: Allison should add in a basal rate of 1.0 units/hr (total daily insulin dose is greater than 20 units) at 9:00 p.m. (2 hours before the pattern of hypoglycemia). She should recheck her basal rates with the change. References: Retrieved August Walsh, J. & Roberts, R. (4 th ed). (2006). Pumping insulin. San Diego: Torrey Pines Press. Wolpert, H. (2002). Smart pumping for people with diabetes. American Diabetes Association.