Perhaps the only advantage to this program is the ease of administration. Only two injections per day are required, and premixed formulations eliminate the possibility of accidentally taking the wrong type of insulin. They also do not require multiple steps to mix the insulins together. Taking NPH insulin twice daily also virtually guarantees that some basal insulin is always present, thus minimizing the risk of ketoacidosis.
Taking two doses of premixed insulin has obvious drawbacks and limitations. However, it may prove practical for those who are unwilling or unable to utilize a more sophisticated program safely and consistently.
Option 2: Morning mixed and evening split
Breakfast: NPH and rapid insulin
Dinner: Rapid insulin
Bedtime: NPH
Figure 5-10. The action profile of NPH taken morning and bedtime, and rapid insulin taken at breakfast and dinner
There are a few differences (and improvements) between this program and Option 1. The user mixes the morning dose manually (rather than using premixed insulin), so you can adjust the dose of rapid insulin based on the amount of carbohydrate consumed. Likewise, the dinner rapid insulin is not part of a premixed formulation and can be adjusted as needed. By moving the evening NPH from dinner to bedtime, the peak is shifted to early morning (around the time of the dawn phenomenon), thus improving the chances for stable glucose levels during the night.
Otherwise, the disadvantages still abound. You must structure and monitor midmorning, midday, and afternoon food intake and physical activity carefully. You have little schedule flexibility. And you still have morning and evening injections of NPH that you must take on schedule but whose action profiles may vary from day to day.
This program may be of some practical use for those who depend on a caregiver to administer insulin injections. If the caregiver is unavailable to administer insulin in the middle of the day (e.g., during the school day), you utilize the morning NPH to offset the glucose rise from midday meals and snacks (albeit not very effectively). It may also work for anyone whose schedule is highly consistent from day to day.
Option 3: MDI with bedtime NPH
Breakfast: rapid insulin
Lunch: rapid insulin
Dinner: rapid insulin
Snacks: rapid insulin
Bedtime: NPH
Figure 5-11. The action profile of NPH taken at bedtime and rapid insulin taken at each meal and snack
Now we enter that zone we call multiple daily injection (MDI) therapy. People used to go to great lengths to avoid taking more injections, but then reality set in. Rational people came to realize that the injections are probably the easiest thing about living with diabetes. The rigid, restrictive lifestyle and uncontrolled blood sugars are what are really hard to live with. An MDI program minimizes these types of major drawbacks, all at the small price of a few extra virtually pain-free injections each day.
With this specific type of MDI program, NPH insulin taken at bedtime provides an early-morning peak to cover the dawn phenomenon as well as a prolonged “tail” of action that ensures the presence of at least some basal insulin throughout the day. However, the peak and duration of NPH can vary from day to day, putting the user at risk for unanticipated high or low blood sugar levels in the morning. Furthermore, the tapering action of the insulin in the afternoon and evening may result in a blood sugar rise between meals late in the day.
This type of plan requires an injection of rapid-acting insulin at every meal and snack, although snacks that are very low in carbohydrate may not require an injection. What qualifies as a “free” snack (not requiring insulin) varies from person to person. In general, the smaller your body size, the more sensitive you will be to small amounts of carbohydrate. For example, someone who weighs 250 pounds (120 kg) might be able to tolerate 10 grams of carb without needing any insulin, but someone who weighs 50 pounds (24 kg) might need insulin for as little as 3 to 5 grams of carb.
Many people find that insulin pens make frequent injections less of a chore. Pens that deliver in half-unit or whole-unit increments are available. And for those who despise the needle sticks, an injection port can be used. (See resource listings in Chapter 10.) Those who use syringes have the option of mixing their evening dose of NPH with rapid insulin if needed to cover a high glucose reading or a bedtime snack.
Taking rapid-acting insulin with each meal and snack restores freedom of choice because you can match the insulin doses to the amount of carbohydrate being eaten. It also allows adjustments for variations in physical activity as well as timely corrections for glucose readings that are above or below target. Details about fine-tuning mealtime doses of insulin will be covered in Chapter 7.
Option 4: MDI with injected basal insulin
Morning or evening: glargine
–or–Morning and evening: detemir
and
Breakfast: rapid insulin
Lunch: rapid insulin
Dinner: rapid insulin
Snacks: rapid insulin
Figure 5-12. The action profile of basal insulin taken once or twice daily as well as rapid insulin taken at every meal and snack
Glargine (Lantus) and detemir (Levemir) are the first insulin formulations that serve as true basal insulins. In some individuals Lantus may show a slight peak six to ten hours after injection and may dissipate earlier than twenty-four hours. But for most people it provides a steady level of basal insulin for about twenty-four hours. Detemir should be taken twice daily due to its shorter duration of action (usually eighteen to twenty-two hours). Each injection of detemir has a mild peak four to ten hours after injection and then tapers off gradually. But when taken twice daily, there are few noticeable peaks and valleys.
Use of basal insulin has its pros and cons. Its consistent absorption and lack of a true peak minimizes the risk of hypoglycemia, although glucose levels may tend to drop gradually between meals during the daytime hours because the dose is usually set high enough to meet basal needs during the night. The peakless nature of these insulins may not be optimal for those with a pronounced dawn phenomenon, whereby basal insulin needs to increase sharply in the early morning hours.
As with any MDI program, injections of rapid-acting insulin are necessary with every meal and snack. And unlike NPH, which can be mixed in the same syringe with rapid-acting insulin, glargine and detemir must be injected separately from rapid insulin.
Option 5: MDI with injected basal and bedtime NPH
Morning: glargine or detemir
and
Bedtime NPH
and
Breakfast: rapid insulin
Lunch: rapid insulin
Dinner: rapid insulin
Snacks: rapid insulin
Figure 5-13. The action profile of basal insulin taken in the morning, NPH taken in the evening, and rapid insulin taken at each meal and snack
Despite requiring the most injections (two to three shots of basal insulin daily plus rapid-acting insulin at each meal and snack), this program comes about as close as one can get to “thinking like a pancreas” when using injections instead of a pump. A low dose of injected basal insulin (glargine or detemir) maintains relatively steady glucose levels between meals during the day, and a nighttime dose of NPH offsets the dawn phenomenon in the middle of the night and early morning. The dose of NPH can be adjusted based on factors that might influence overnight glucose levels, such as illness, heavy exercise during the day, and high-fat meals late in the day. For those with a pronounced dawn phenomenon and a need for very flexible dosing of both basal and mealtime (bolus) insulin, this program might be right for you.
Option 6: Insulin pump therapy
Figure 5-14. The action profile of insulin pump therapy
Insulin pumps are beeper-sized, battery-powered devices that infuse rapid-acting insulin just below the skin. Pumps are programmed to deliver tiny pulses of insulin every few minutes throughout the day and night (basal insulin) along with larger doses at mealtimes (bolus insulin).
The insulin is delivered by way of a small, flexible plastic tube or a tiny needle called an infusion set. The infusion set must be changed every couple of days in order to prevent clogging and infection as well as to ensure consistent insulin absorption.
The infusion set is usually worn on the abdomen, buttocks, or hip. It adheres securely to the skin and is not likely to pull out while you sleep or exercise. Most feature a disconnect mechanism that allows you to temporarily set the pump and tubing aside for situations such as bathing, contact sports, and intimacy, all while leaving the infusion set portion on/in the skin. The tube that connects the pump to the infusion set is very strong and comes in different lengths. Some pumps stick directly to the skin and don’t require any tubing at all. Pumps also have multiple safety features to ensure against accidental insulin delivery.
All pumps are either waterproof or water resistant, and they come with clips that let you attach them to a belt/waistband. A variety of cases, pouches, and fashion accessories make the pump easy to wear in almost any situation. (See Resources in Chapter 10.) A few pumps offer remote-control programming so that you don’t even have to handle the pump when it comes time to deliver a bolus.
Most of today’s pumps have built-in bolus calculators. Enter your blood sugar level and the carbs you plan to eat, and the pump recommends a precise dose based on the dosing formulas you and your health care team programmed. Pumps can even deduct previous bolus insulin that is still working in your body so that you don’t accidentally overdose yourself. Each pump keeps a record of all this information in its memory for on-screen recall or downloading to a computer.
Some insulin pumps receive data via radio transmissions from blood glucose meters and continuous glucose monitors. This is not to say that they deliver boluses of insulin automatically based on your blood sugar, but rather that they can display the information on-screen and you can then use the information when calculating your boluses.
One very unique aspect of pump therapy is the ability to fine-tune and adjust basal insulin levels throughout the day and night. By matching basal insulin to the liver’s normal output of glucose, blood sugars should hold steady between meals and during the night. As a result, you can vary your schedule as much as you like in terms of meals, activities, and sleep—in other words, you can live a more normal life. You can also adjust basal insulin levels on the fly for circumstances such as menstrual cycles, pregnancy, stress, illness, travel, high-fat meals, and extended exercise.
One very unique aspect of pump therapy is the ability to fine-tune and adjust basal insulin levels throughout the day and night.
With insulin pumps, you can administer mealtime insulin at the touch of a button—actually, a sequence of button presses. The doses are highly precise; some pumps permit dosing in increments as low as onefortieth of a unit. All pumps offer the option of delivering mealtime boluses all at once or over an extended period of time—in case you expect your meal to take a while to digest.
Benefits of pump therapy include:
1. Better blood sugars. First and foremost, pump users tend to have lower A1cs and less glucose variability (fewer high-to-low and low-to-high swings) than those on injections.
2. Fewer lows. By using only rapid-acting insulin, there is no long-acting insulin peaking or working too hard at inappropriate times. This makes pump therapy a good choice for those who have frequent lows, a history of severe lows, or a hard time detecting low blood sugars.
3. A more flexible lifestyle. Raise your hand if you can eat, sleep, and exercise at the same times every day. The pump lets you choose your own schedule.
4. Dose calculations. Modern pumps come equipped with a bolus calculator that helps you determine mealtime doses based on carb intake, blood glucose levels, and the amount of insulin still active from previous boluses. Imagine that—no math!
5. Precise dosing. Pumps deliver insulin to the nearest .1, .05 or .025 units—ideal for those who are sensitive to very small doses, such as children and lean/active adults.
6. Convenience. There is no need to draw up syringes every time you need insulin; just reach for your pump and press a few buttons.
7. No Shots. Multiple daily insulin injections can be uncomfortable and cause skin problems, but pumps only require a needle stick once every two to three days to change the infusion set.
8. Easy adjustments for real life. Temporary basal insulin changes help maintain stable blood sugar during periods of growth, illness, seasonal sports, dining out, and menstruation. The ability to deliver boluses all at once or over a prolonged period of time can be instrumental in achieving optimal after-meal glucose control.
9. Weight control. Eat what and when you choose; snacks are not required when you use a pump.
10. Data analysis. Insulin pumps store a plethora of historical information that can be displayed on-screen or transmitted to various computer programs for analysis and fine-tuning.
Potential drawbacks to pump therapy include:
1. Cost. Although most insurance plans cover insulin pumps and supplies, there are often copays and deductibles that must be met.
2. A learning curve. Don’t expect good control right away. You usually need a few months to get the basal and bolus doses regulated and adjust to using the pump correctly.
3. Inconvenience. Wearing the pump around the clock, even during sleep, can become awkward once in a while. My infusion set tubing gets caught on a doorknob at least once a month!
4. Technical difficulties. As mechanical devices, pumps are prone to occasional infusion set clogs, electronic failures, computer glitches, and damage due to typical wear and tear.
5. Skin problems. Skin can become irritated from infusion set adhesive, and infections can occur if infusion sets are worn too long or inserted improperly. Insulin absorption can be hindered if you do not change infusion sets regularly and rotate sites properly.
6. Ketosis. The absence of long-acting insulin with pump use can present a problem if insulin delivery is interrupted for more than a few hours. Blood sugar can rise very quickly, and ketones may appear in the bloodstream and urine if the problem is not corrected.
7. Infusion set changes. Every couple of days you must change your own infusion set. This five- to ten-minute procedure involves numerous steps and can be momentarily uncomfortable or traumatic for the novice pump user.
Certain characteristics and skills are needed to use a pump successfully. After all, just about any idiot with insulin-dependent diabetes and a decent insurance policy can go on an insulin pump, but to succeed with a pump takes preparation and follow-through. The following are some qualities that are most important for those seeking an insulin pump:
•Motivation/interest in going on a pump, keeping in mind that nobody is 100 percent sure that it is right for them until they give it a try. A bit of hesitancy and anxiety about making the switch to a pump are perfectly normal.
•A true state of insulin dependence (type 1 or type 2, with little or no insulin production).
•Adequate resources to afford the pump and ongoing supplies (via insurance or cash).
•Ability to handle basic programming and infusion set change procedures. A guardian can do this if the user is very young or physically/mentally challenged.
Certain skills are essential for making a successful transition to pump therapy. Ideally, these should be mastered prior to starting on the pump:
•carbohydrate counting (using grams rather than exchanges)
•blood glucose monitoring prior to meals and bedtime (four times a day, minimum)
•complete record keeping in paper or electronic form (including blood sugars, insulin doses, carb intake, and physical activities)
•self-adjustment of insulin doses (based on blood sugar levels, carb intake, and physical activity)
•an understanding of the basic principles of pump therapy (including the components of a pump and infusion set as well as the role of basal and bolus insulin)
Successful pump u
se will also require adequate follow-up and finetuning. This should include
•basal rate testing throughout the day and night (fasting for eight- to ten-hour intervals and testing blood sugars to see if they are holding steady);
•fine-tuning of bolus formulas (based on record keeping);
•troubleshooting and preventing emergencies such as DKA (diabetic ketoacidosis); and
•using advanced pump features such as extended boluses and temporary basal rates.
To learn more about pump therapy, contact one of the insulin pump manufacturers listed in Chapter 10 or ask your physician or diabetes educator. Find out if there are insulin pump user groups in your area. Group meetings offer an excellent forum for meeting other pumpers and finding out about their personal experiences since starting pump therapy.
Substitution Is Permitted
When selecting an insulin program, don’t think of it as a lifetime commitment. Many people switch plans because of changes in their lifestyle or simply because a particular plan fails to do the job. Several of my clients have tried an MDI program but were unable to achieve the kind of control they wanted, so they made the move to a pump. I have also had pump users who switched back to injections, either permanently or temporarily, due to image concerns or the desire for more structure in their lives. The one constant in life is change—you are not locked into any particular plan.
Think Like a Pancreas Page 12
