Diabetes and Lipid Clinic of Alaska

 

 


Pump Tips: Bolus Dosing

There is no one "right" way to bolus, each person must learn their own responses and patterns. Only through faithful recording and trial and error will you learn what works best for you! Assuming that you are already matching your foods and insulin through accurate carbohydrate counting, these suggestions may help you answer some questions.

  • Bolus after the meal for people whose "eyes are bigger than their stomach"
  • Bolus before the meal for what is on the plate if you are sure it will be eaten, then bolus again after for any "seconds or extras"
  • If your blood sugar is low when you check right before the meal, calculate a "negative correction" which is simply subtracting a certain amount of bolus from the insulin dose needed for the meal. Try a 10 - 25% decrease in the meal bolus.
  • Do not correct between meal high blood sugars too readily. The type of the bolus (square or dual) is as important as the amount of bolus itself. How will you know? Blood sugar is high 2 hours after the meal (>140)
  • Corrections taken at this time cause low blood sugar before the next meal.
  • Changing the timing of boluses can be done using the extended and dual wave bolus features on the pump
  • Or try - bolusing 10 - 15 minutes before the meal.
  • Using the extended or dual wave feature of your pump is a good way of solving problems such as high blood sugars3-4 hours after a meal high in fat, or in the case of slowed digestion.
  • Try a calculation of 70% "Now" and 30% over the next 1 -2 hrs. Check blood sugar 2 hours after the meal to see whether this is working for you.
  • Try varying the length of time the bolus is extended, and the percentage of "up-front" bolus. It may be that you need 50% now and 50% delivered over an hour. Make sure you have the correct bolus amount before you start changing the timing.
  • You have taken too large a bolus if two hours after the meal your blood sugar 80 or less. Better have a snack!
  • For kids at school: don't bolus for snacks of 15 - 20g eaten before recess.
  • Also for kids: find out what time gym time is. If it is first thing in the morning or right after lunch, the meal bolus just before class will have to be decreased by about half (50%)

The Bolus Wizard Calculator is a feature on the Medtronic Paradigm REAL Time insulin pump. Other pumps have a similar feature as well as may include a food diary This tool can assist the pump user in calculating insulin doses for mealtimes or correcting high blood sugar values. The “Wizard” on board calculator tool should not be a substitute for good judgment or proper problem solving diabetes management practices. The Bolus Wizard Calculator is a feature on the new Paradigm REAL Time insulin pump. This tool can assist the pump user in calculating insulin doses for mealtimes or correcting high blood sugar values. The “Wizard” on board calculator tool should not be a substitute for good judgment or proper problem solving diabetes management practices. This document is meant to help you learn about the benefits and limitations of the Bolus Wizard and how to best maximize its use.

Specifications of the Bolus Wizard

  1. Option is “OFF” by default from the factory. All settings must be complete before the Bolus Wizard can be used.
  2. The wizard’s calculator tool uses either manually entered BG values or BG values received from the Link Meter.
  3. Calculator uses the following information to determine a BOLUS insulin dose:
    1. BG (manually entered or beamed to pump from the BD Link meter)
    2. Individual insulin to carbohydrate ratio.
    3. Insulin Sensitivity Factor (ISF) also known as a “correction factor”
    4. Your target pre-meal blood glucose range is set specifically for you.
    5. Active insulin (insulin from last correction BOLUS still exerting an effect on your blood sugar.
    6. We refer to the individual factors as your “ratios”
  4. An “estimate” is created for you to review prior to accepting and delivering the suggested amount of bolus

Procedure for Implementing Bolus Wizard

*Remember, we are aiming for success, not perfection!

  1. Talk to your health care provider. Have you determined your ratios? When were they changed last? Have they been verified by post-meal blood sugar checks?
  2. If you are just beginning pump therapy, it is best to establish the basal rate(s) prior to setting up the bolus wizard.
    a. Your ratios will change when you start pump therapy as your total daily insulin dose changes. Therefore the ratios that worked for you when you were on injections may not work for you on a pump.
    b. Work with your Diabetes Care Team at the Diabetes and Lipid Clinic of Alaska to help you establish and adjust your ratios.
  3. If you are moving from one model of pump to another and have verified your ratios, you may set up the Wizard when you feel comfortable with the other programming changes.
  4. If you have been using a pump for a while but not consistently using carbohydrate ratios or insulin sensitivity factors to bolus, you may need to “re-tool” to get the most out of your new Paradigm Pump. Speak with a Medtronic MiniMed Certified Insulin Pump Trainer or diabetes educator to help you with this.
  5. If you are unsure of the Bolus Wizard functions, then DO NOT activate it!

Tools for setting up your Bolus Wizard:

  • Pump User Guide
  • Record of your individual ratios
  • Your pump

* Remember to write down all of your pump settings each time you make a change.

Making “Active Insulin” Work for You

“Active insulin” is the term for what is also known as the “un-used insulin” rule. The basis of the active insulin formula incorporated into the pump functioning is from clinical studies looking at the curve of glucose uptake vs. time. Glucose uptake is how fast the body uses up the insulin. Active insulin only takes bolus insulin into account: not basal which should be considered “background” insulin.

The following are some Frequently Asked Questions (FAQ’s)

Q. When does the pump consider “Active” Insulin?

A. “Active insulin” is only taken into consideration by the Bolus Wizard if there has been a correction bolus within a certain time frame established by the formula in the pump. The pump determines how much of the previous correction bolus has exerted its’ effect on your blood sugar and how much of it is yet to be active. Active insulin does not consider either basal insulin or bolus insulin to cover carbohydrates.

Q. Will the Bolus Wizard consider my activities when it suggests a bolus? Does active insulin stand for activity?

A. No, the Wizard is not a replacement for your own good judgment. If you plan on being active after a bolus, it is up to you to decide how much if any, insulin you wish to reduce or you may prefer to use a temporary basal rate depending on the type and duration of exercise you are planning. You can still use the Bolus Wizard to help you calculate your meal, correction and Active insulin. Once the bolus estimate screen is shown and before you activate the bolus, it is up to you to make any changes. You can still change this amount by using the scrolling keys (arrows) before deciding on a bolus dose. The Bolus Details screen will store what you actually took.

Q. What if I only use the Bolus Wizard some of the time? Will it still know what I have taken?

A. Yes, though you may not have used the Bolus Wizard to program a dose and used the express bolus instead, the Wizard will still factor in the Active Insulin (if any is left) the next time you use it.

Q. I am nervous about using the Bolus Wizard feature of my pump. What can you tell me to reassure me that it is safe?

A. The Bolus Wizard is a tool. Think of it as a calculator that you carry along with your pump. Would you trust the information it displayed? Now consider that instead of carrying it with your pump, it is in your pump. If you answered “yes” to the first question but feel that you would not trust the suggested amount on the pump you may be concerned unduly. Start with writing out your own calculations. Review what the Wizard suggests, but use your own judgment before selecting a dose. You always have the choice of whether or not to “activate” on the Wizard’s estimation and deliver the dose. Remember, there is no substitute for the Bolus Wizard between our ears!

Your Bolus Wizard Checklist:

  • I have met with a pump trainer to determine my individual ratios.
  • I have tested my basal rates and know they are current.
  • I have read and understand the Paradigm pump user guide.
  • I have recorded my pump settings.
  • I understand how to read the “Bolus Wizard Estimation” screen on the pump.
  • I understand the rationale for the Bolus Wizards’ calculation.

Success with the Bolus Wizard may take some practice to make it work for you. With time and effort, your skills working with the calculator and fine tuning your rates will improve. Even the most precise insulin delivery system cannot foresee changes which need to be made to your diabetes management. Be realistic about what the Bolus Wizard can do for you.

The Dual and Square Wave Bolus

This Variable Bolus feature is designed to help people better match insulin action to insulin need during periods of extended eating or to compensate for delayed digestion (gastroparesis).

In the past, these situations were addressed by recommendations to either split larger boluses into multiple smaller boluses spaced throughout a long meal, or to set a temporary basal rate to function as an extended bolus. Both of these situations were complicated and presented the possibility of making errors.

To make this process safer and easier, Medtronic Diabetes developed the Square Wave and Dual Wave Boluses. The Square Wave Bolus allows patients to easily select an amount and duration (from 30 min to 8 hrs) over which time a meal bolus is to be delivered. The Dual Wave Bolus simply combines a Square Wave Bolus with a Normal bolus and delivers them at the same time.

The Variable Boluses can be helpful in the following situations, whether using regular insulin or the newer rapid acting insulin analogs, when they become available for pump use.

  • Prolonged Meals Banquets
  • Formal Dinners
  • Holiday Feasts
  • Extended Snacking
  • Receptions
  • Spectator Sporting Events
  • High Fat Meals (e.g., pizza)
  • Gastroparesis (delayed digestion)

Matching Insulin Action With Carbohydrate (CHO) Digestion:

For prolonged meals, the insulin action of a standard bolus is too quick to adequately compensate for the carbohydrate (CHO) digestion. Glucose levels go high after meal.

For gastroparesis (slow digestion), insulin action peaks before carbohydrate digestion occurs. Glucose levels run high after meal.

Using a Square Wave Bolus, insulin action matches the carbohydrate digestion of prolonged meals or gastroparesis. Insulin levels remain in target range after meals.

Use of the Dual wave feature:

The dual wave is a way of delivering a bolus where the pump gives a set amount now and the rest over an amount of time that you enter into the pump. People using pumps actually get better blood sugars after meals if they learn how to use this function. It is an extra step in the process therefore uses it only for large meals that will take a long time to digest or high fat /fiber meals which can slow the absorption of the carbs. So, usually not needed for breakfast or lunch though you may wish to use it. I would recommend trying starting with 50% now and the other half delivered over the next 2 hours. Some people find themselves still high at 2 hours later which would mean that they need to give 70% now and the other 30% over the next 2 hours. This is individual and like everything else, based on trial and error. It may be that you need to extend your bolus for 3 or 4 hours to cover the food. If you find yourself under 6 at the two hour mark, you may wish to cancel the rest of the bolus, do this by just putting the pump into suspend then removing the suspend the same way you would cancel any other bolus. You may be on the rise though so the only way to know is to test your BG every hour after the 2 hr post meal sugar.

This is a confusing aspect of pump therapy, and one that I usually deal with after the pumper has been doing regular boluses for a month or so. That being said, if we are not getting good control for the next 4 hours after a Normal bolus, there is no other option but to try something different. You may be wondering why your blood sugar stays up for so long after you bolus:

  • High fat meal slows the absorption of carbohydrates
  • Your stomach emptying is slowed down due to a nerve problem related to your diabetes.

High stomach acids are affecting how your food is absorbed. No matter what the reason, any or all of the above, we need to deal with the high post meal spikes.

Determining what type of boluse one should use takes time and patience. Remember to utilize the pump to its full capabilities and break old habits if they exist. If your diabetes is perfectly controlled without highs or lows with little effort, you are one of the few and fortunate patients. Consult with us at the Diabetes and Lipid Clinic of Alaska for additional information and consultation.

The information on this Web page is provided for educational purposes. You understand and agree that this information is not intended to be, and should not be used as, a substitute for medical treatment by a health care professional. You agree that Diabetes and Lipid Clinic of Alaska is not making a diagnosis of your condition or a recommendation about the course of treatment for your particular circumstances through the use of this Web page. You agree to be solely responsible for your use of information contained on this Web page

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