Primary Care Reports January 27, 1997

A Primer on Intensive DiabetesManagement and Insulin Pump Therapy

Authors: Jeffrey R. Unger, MD, Chino Medical Group, Inc., Chino, CA; Linda P. Fredrickson, MA, RN, CDE, Director, Professional Education and Clinical Services, MiniMed, Sylmar, CA.

Peer Reviewer: Ralph R. Hall, MD, Professor and Associate Dean, University of Missouri at Kansas City School of Medicine, St. Luke’s Hospital Division, Kansas City, MO.

Editor’s Note—The primary care physician often treats patients with insulin-dependent diabetes mellitus who use conventional insulin therapy (1-2 injections per day with minimal blood glucose testing). The publication in 1993 of a landmark 10-year study funded by the National Institutes of Health1 demonstrated that improved glucose levels significantly reduced the incidence and progression of diabetic complications. Since then, more and more physicians and patients are practicing intensive diabetes management (³ 3 injections per day or insulin pump therapy with blood glucose testing 4 times daily) in order to improve glucose control. The role of the primary care physician is explained in this issue relating to the benefits and use of intensive diabetes management therapies and, in particular, insulin pump therapy. Practical guidelines are given for pump therapy (i.e., the "nuts and bolts" of how a pump works), as well as formulas for starting pump dosages and guidelines for the prevention of adverse events. In addition, guidelines are given for carbohydrate counting, exercising, the use of the pump during pregnancy, and candidate selection.

Introduction to Insulin Pump Therapy

Between 750,000 and 1 million Americans have insulin-dependent diabetes mellitus (IDDM), with 30,000 new cases diagnosed each year.2 It has been proven that the long-term complications of diabetes can be significantly delayed and/or prevented by maintaining glycemic control as close to the normal range as possible throughout the patient’s lifetime. People with diabetes are usually unable to achieve ideal blood glucose control unless they are intensively managed. (See Table 1.) Insulin pump therapy, or continuous subcutaneous insulin infusion (CSII), evolved in 1974 from the desire to develop insulin delivery that simulates normal pancreatic function for people with IDDM.3 Through a continuous "basal" insulin infusion and incremental, or "bolus," insulin administration at meal times, CSII provides a more normal physiological insulin delivery than possible with conventional injection therapy.4

The acceptance of insulin pump therapy increased following the Diabetes Control and Complication Trial (DCCT), the 10-year study funded by the NIH and published in 1993. The DCCT demonstrated that improvement in glycemic control can significantly reduce by 60% the incidence of microvascular complications (retinopathy, neuropathy, and nephropathy).1 In the DCCT, patients achieved intensive control either with three or more injections daily or with the use of an insulin pump. At the end of the study, 42% of all the intensively managed patients were using pump therapy.5 Currently, 3% (32,500) of U.S. patients with IDDM are treated with CSII. (See Figure 1.) As shown, this number has been steadily increasing, which indicates that more and more physicians and patients are accepting insulin pump therapy as an option for intensive diabetes management.

Most patients with diabetes are treated by primary care physicians whose speciality is not diabetes or endocrinology.6 Patients who use CSII are usually knowledgeable about diabetes and insulin pump therapy. When these patients move or join new insurance providers, they frequently encounter a physician who has limited or no knowledge of CSII. These patients may be told that "insulin pump therapy will not work," or "insulin pumping is just a fad." However, very few patients are willing to give up pump therapy to return to multiple daily injections. As a result, many pump patients stop seeing these healthcare providers who are not familiar with pump therapy. Therefore, it is becoming more important for the primary care physician to know the mechanics and principles of insulin pump therapy and of intensive diabetes management.

Benefits of Continuous Insulin Infusion

With injection therapy, absorption from the injection site with the use of intermediate- and long-acting insulins does not provide a constant basal rate due to their highly variable absorption, which ranges from 10% to 52% of the injected daily dose.7 Variable insulin absorption is responsible for up to 80% of the day-to-day fluctuation in blood glucose concentrations in persons using injection-based therapy.8 With CSII, patients use only regular insulin, in which there is far more predictable absorption, varying by less than 2.8% from the administered 24-hour dose.7 CSII provides the greatest day-to-day reproducibility in insulin availability and the least unexpected fluctuation in glycemic control.

In the past, insulin pump use was contraindicated in individuals with severe, recurrent hypoglycemia. However, pump therapy, with its more predictable delivery of insulin, has been shown to reduce the incidence of severe hypoglycemia.9-12 Newer studies have shown that CSII should be considered as an important indication for patients with frequent severe hypoglycemia.12-14

Another indication for insulin pump therapy is extreme insulin sensitivity (total daily dose < 20 units per day).15 The pump permits convenient administration of fractional insulin units (in 0.1 unit increments), a level of precision not available with injections.

Pump therapy allows individuals to lead a more normal lifestyle. Pump users are able to experience a degree of freedom in the timing of meals, work, sleep, and physical activity not possible with the conventional treatment of multiple daily injections (MDI). Diabetes treatment protocols that rely on rigid dieting and activity schedules are unrealistic and inconvenient for most people. Having that freedom without loss of diabetes control is thought to be a major reason for the decreased depression and greater perception of self-efficacy found among pump users.16

How Does the Pump Work?

Although the original pumps were quite large and weighed close to 2 pounds, patients with diabetes were still able to master this form of therapy and achieve near normal glycemic control.17,18 Today’s insulin pumps weigh only 4 ounces and are about the size of a beeper. (See Figure 2.)

Insulin pumps use a flexible infusion set with catheter lengths of 24 or 42 inches to facilitate placement inside or outside clothing. A 24-gauge soft catheter or 27-gauge bent needle is located at the far end of the plastic tubing. The insertion site is cleaned with alcohol or Hibiclens before inserting the needle into the chosen infusion site. The majority of pump wearers use the abdomen as the infusion site, although the buttocks or arms can be used. (See Figure 2.) The newer catheters have a Quick Release (MiniMed, Inc., Sylmar, CA) feature, which allows the patient to separate the catheter from the insulin syringe/reservoir located within the pump for bathing, exercise, or intimate activities. The insulin is located within a 3 cc syringe/reservoir on the pump. The syringe and infusion set must be filled and changed every 2-3 days by the patient. Prolonged use of the infusion set at a single site could result in irritation at the infusion site or the formation of a superficial abscess requiring surgical drainage in the office.15 The pump is powered by disposable batteries which last approximately eight weeks.

The physician sets and programs the pump infusion parameters into the pump’s memory. Each pump comes with specified built-in alarms to prevent inadvertent insulin delivery or to warn the patient if the infusion set becomes clogged or dysfunctional.19

Principles of Insulin Pumping

1. Establishing the pump parameters. (See Figure 3.)

When initiating any form of intensive diabetes management, the physician must first determine the total daily dose of insulin that the patient will require. Because many patients need less insulin when beginning CSII,14 the prepump total daily dose is reduced by 10-25%. Approximately 50% of the adjusted total daily dose of insulin is used as "basal insulin," and the other 50% is given prior to meals as "bolus insulin."20 CSII uses basal insulin to maintain hepatic glucose output equivalent to peripheral basal glucose utilization.19 Insulin given as a bolus prior to eating will control postprandial hyperglycemia.

Basal rate. To program the basal rate, 50% of the reduced total daily insulin dose is divided by 24 hours. The patient with a prepump total daily dose of 54 units would have a basal rate equal to 50% of the reduced total daily dose of 40 units, or 20 units. This rate is then divided by 24 hours, for an hourly rate of 0.8 units. The most commonly used insulin pumps have the capability of programming 12 different basal rates. However, the majority of patients require only 2-3 basal rates.14 If a patient has significant early morning hyperglycemia, a second basal rate can be programmed to counter the "dawn phenomenon," which occurs due to the production of growth hormone and cortisol, both of which raise fasting blood glucose levels and result in insulin resistance.21 By increasing the basal rate 0.2-0.4 units per hour beginning 2-3 hours prior to rising, patients will be able to arise with normal blood glucose levels.21

Bolus dosages. Premeal insulin bolus doses should be determined according to: a) the preprandial blood glucose levels; b) estimation of the grams of carbohydrates that will be consumed during that meal; and c) anticipated activity level after eating.22

2. Meal planning

Diabetes interferes with the metabolism of carbohydrates. Therefore, the more carbohydrates consumed in a meal, the higher the anticipated rise in postprandial blood glucose, since carbohydrates are completely metabolized into glucose. Bolus insulin can be determined as demonstrated in Figure 3.

Correcting high blood glucoses. Supplemental insulin can also be given with the routine preprandial bolus to correct any high blood glucose levels that are present before eating. The supplemental insulin dose is based on the "1500 rule."14,23 This rule calculates the patient’s insulin sensitivity factor and allows the patient to predict how much 1.0 unit of insulin will lower the blood glucose. The formula is depicted in Table 2. Using the example in Table 2, for a patient whose TDD is 50 units, 1.0 unit of insulin will drop blood glucose by 30 mg/dL. Therefore, a blood glucose level of 160 mg/dL would require a 2.0 unit supplement of insulin to reach the preprandial target of 100 mg/dL. The 2.0 unit supplement would be added to the normal meal bolus used to cover the carbohydrates in the meal.

Determining insulin sensitivity is particularly important in assisting patients to avoid extremely labile swings in blood glucose (i.e., over-correcting for an increased blood glucose and then becoming hypoglycemic several hours later). Meal planning for patients with IDDM is an essential aspect of intensive diabetes management; many are often frightened by the term "diet." Physicians all too often prescribe the standard "1800-calorie American Diabetes Association diet" for all patients with diabetes regardless of age, weight, activity level, or total daily insulin requirements. People with diabetes require a careful balance of food intake, activity level, and insulin dosage. When patients learn the influence of various foods and activities on glycemic levels, they are able to balance these components of diabetes management at an optimum level.

Counting carbohydrates. When discussing meal planning with the patient, physicians should emphasize the importance of sound nutritional practices, including avoiding excess intake of saturated fats and cholesterol, limiting salt consumption, and avoiding foods that have a high glycemic index, which could result in a rapid rise in plasma-glucose levels.24 Unless the patient is overweight, there is no need to limit calorie consumption. Recently, health care professionals have begun teaching intensively treated IDDM patients how to count carbohydrates.25 This simple concept requires that the patient learn to dose insulin according to the amount of carbohydrates consumed.

In order to successfully count carbohydrates, patients must be familiar with the effects of carbohydrate consumption. For most people, 5 g of fast-acting carbohydrate will raise the blood glucose by about 20 mg/dL.26 Thus, a 30 g carbohydrate meal will result in a 120 mg/dL rise in blood glucose within 90 minutes of consumption. Next, the patient can be given an insulin-to-carbohydrate coverage ratio to help calculate the dose of insulin required to cover the ingestion of a given amount of carbohydrate. One unit of insulin will usually cover 10-15 g of carbohydrate.27 However, this ratio will have to be individually adjusted for each patient. In general, patients who have smaller body size and are extremely insulin-sensitive will require less insulin and more precise calculations.28

Patients should be encouraged to read food labels and estimate the amount of insulin required to cover the carbohydrate load contained within a meal. Eating a meal high in carbohydrates will require an increased meal bolus, whereas eating a small amount of carbohydrates requires bolusing less insulin. The patient should also understand that sugar-free foods may not contain sucrose but might contain other forms of carbohydrate that would require the use of insulin. Snacks will also require bolus insulin. A patient who goes to a movie and eats a box of popcorn will need to take insulin, or blood glucose will rise substantially. Therefore, patients need to be aware that all carbohydrate consumption must be matched with appropriate insulin boluses.

With practice, carbohydrate counting becomes commonplace. During the initiation phase, patients must learn to check postprandial blood glucose levels 1-2 hours after the meal to see if they fall within a target range. (See Table 3.) If the blood glucose levels fall outside of the target range, adjustments must be made to the amount of insulin taken as a bolus prior to consuming that same amount of carbohydrates next time a similar meal is eaten. Patients who fail to achieve normal glycemic control following a given meal are advised to eat the same meal the following day and attempt to make the appropriate insulin adjustments. Using standard meals will decrease the variability encountered during the evaluation or reevaluation phase of CSII. Once the target goal is attained, teach the patient to remember how much insulin is required for commonly consumed meals. Food diaries containing information on matching insulin dosing with commonly eaten foods are especially helpful.

Intensively managed patients must ask the following five questions prior to preprandial bolus dosing of insulin:

1. What is my blood glucose now?

2. What type of food will I be eating, and is the meal high in carbohydrates?

3. How much insulin do I need to cover this meal?

4. What happened to my blood glucose the last time I gave this dose of insulin for this amount of food?

5. Is there any anticipated postmeal exercise planned?

3. Exercising with the insulin pump

A regular exercise program can potentially improve glycemic control in nearly all diabetic individuals. Clear-cut cardiovascular benefits accrue to patients who participate in a program of regular exercise.29 The effect of exercise is dependent on several factors: 1) intensity and duration of exercise; 2) degree of physical conditioning of the individual; 3) preexercise diet; 4) dosage and timing of insulin taken prior to exercise; and 5) duration of the diabetes. Nearly all people can perform some type of exercise including walking, biking, aerobics, weight training, swimming, running, or chair exercises. Caloric expenditure of 500-3500 calories weekly will result in increased longevity, improved glycemic control, and weight maintenance. Walking for 20 minutes four times weekly is sufficient exercise for most people with diabetes. Exercise can also improve an individual’s sense of well-being and quality of life.30

General health status. Prior to beginning an exercise program, a physician must evaluate the patient for evidence of eye, kidney, nerve, or cardiovascular problems that might prohibit certain types of exercise. Loss of sensation in the feet can result in weakened arches, increased callous formation, joint damage, and pressure ulceration. Patients with neuropathy should perform low-impact, high-intensity exercise such as swimming and biking. Running is contraindicated in patients with neuropathy due to loss of proprioception and balance mechanisms. Patients with proliferative retinopathy should avoid resistance weight training because of an increase risk of retinal detachments. An exercise-stress ECG is recommended for all patients over 35 years of age. This test will help identify silent heart disease and may identify patients who have an exaggerated hypertensive response to exercise and/or may develop postexercise orthostatic hypotension.30

Blood glucose goals. Patients with IDDM should begin exercise within a target blood glucose of 120-180 mg/dL. Intensive exercising below 120 mg/dL may result in hypoglycemia. The symptoms of hypoglycemia are similar to those seen commonly with exercise—palpitations, sweating, dizziness, and fatigue. If the blood glucose is below 120 mg/dL prior to exercise participation, the patient can consume 15-25 g of carbohydrates such as a fruit or a carbohydrate-enhanced "power bar" in order to elevate the blood glucose to the target range. An absolute deficiency of insulin will result in impaired glucose uptake, hyperglycemia, and ketosis;31 therefore, patients should not exercise if the blood glucose is above 240 mg/dL. At this level, exercise will cause insulin levels to drop, with a consequent rise in blood glucose levels that can cause ketosis.

Temporary basal rate. During exercise, the insulin pump offers several advantages over multiple daily injections. In anticipation of exercise, the pump can be stopped or slowed down using a temporary basal rate (TBR).32 A TBR allows the patient to bypass the programmed basal rate in favor of one that is either decreased or increased. Thus, a lower TBR can be set prior to the anticipated exercise start time so that circulating exogenous insulin levels begin to fall. The TBR should be continued throughout the exercise period as well as several hours after exercise is completed in order to avoid postexercise hypoglycemia.33

A well-conditioned athlete who is performing the same level of intense exercise on a routine basis may not have to alter his insulin delivery rate at all. However, if an athlete is poorly conditioned, the blood glucose will drop rapidly and remain low in the fasting state for up to 12 hours after exercising.33,34 The guidelines for exercising with an insulin pump are summarized in Table 4.35

Risk Assessment and Prevention

Any diabetes treatment plan carries potential risks to the patient. Proper education, close monitoring, and adherence to recommended guidelines are the cornerstones to dealing with problems unique to pump therapy and preventing minor problems from escalating into adverse events.

Hypoglycemia. Patients undergoing intensive diabetes management are at increased risk for developing hypoglycemia. During the DCCT, severe hypoglycemia, defined as a hypoglycemic episode requiring assistance of another person, was increased threefold in the intensive therapy group in comparison to the conventional group.36 Of severe hypoglycemic episodes, 53% occurred during sleep, and 35% occurred without warning symptoms while patients were awake. Patients who have had IDDM for more than five years often lose their counterregulatory mechanism for identifying and metabolically reversing hypoglycemia.37 These patients often develop "hypoglycemic unawareness,"38 functioning fairly well with blood glucoses as low as 40 mg/dL. The most dangerous consequences of hypoglycemia are impaired cognitive and disordered intellectual functioning, making self-medication and reversal of hypoglycemia impossible.39 This could be very dangerous if hypoglycemia occurs at a time when concentration and cognitive thinking are essential, such as while driving a car, working in the operating room, or taking care of small children. Strategies to prevent hypoglycemia include the following:

Setting higher target glucose goals. Insulin pump therapy offers several advantages in preventing hypoglycemia. If the patient on multiple daily injections is experiencing frequent wide glycemic swings including hypoglycemia on a daily basis, placing the patient on an insulin pump will permit the physician to aim for higher target blood glucose levels.14 Setting a lower than normal basal rate, the blood glucose levels will rise, and the patient will experience fewer episodes of hypoglycemia. Blood glucose targets can be set in the range of 120-180 mg/dL instead of 70-130 mg/dL. After resetting the target blood glucose range and maintaining that target for 6-8 weeks, the basal rate can be increased once again, allowing the physician to lower the target blood glucose range closer to normal. Hypoglycemic awareness has been reported to be re-established in patients using this technique to avoid hypoglycemia.40,41

Hypoglycemia treatment guidelines. Patients with frequent hypoglycemia who eat to raise blood glucoses will often gain weight and require even more insulin to control their glucose levels. CSII allows the patient to avoid "eating their way out of hypoglycemia" by decreasing the basal rate when hypoglycemia occurs. Hypoglycemia that does not improve with these modalities can be treated with glucose tablets that contain 5 g of carbohydrates. (See Table 5.) All people with diabetes should have access to glucagon for the treatment of severe hypoglycemia, and their family members or significant others should know how to administer the injection.

Blood glucose monitoring guidelines. Many patients using intensive diabetes management do so in the hope of avoiding the long-term diabetes complications. They may not view a low blood glucose value as dangerous as a high blood glucose value. Physicians need to educate patients on the two problems caused by repeated episodes of hypoglycemia. First, repeated episodes blunt hormonal defense mechanisms that prevent hypoglycemia; second, they lower the level at which early hypoglycemic symptoms are perceived. Understanding the principle that hypoglycemia begets more hypoglycemia,42 patients must be taught how to be their own "glucose sensor" based on frequent self-monitoring of blood glucose (SMBG) levels.43 Blood glucose levels should be monitored at least four times per day in all patients—before each meal, at bedtime, prior to driving and before exercising. In addition, once a week a blood glucose test should be performed three hours after going to bed in order to detect nocturnal hypoglycemia.

Skin infections. Skin irritations and skin infections may appear at the infusion site. Occasionally, an abscess may occur and must be surgically drained. Most infections are caused by coagulase-positive Staphylococcus aureus.44 Infections usually occur because the patient fails to change the infusion set at the appropriate interval. Infusion sets with the soft cannula (Sof-set) can be changed every three days. Bent needle sets must be changed more frequently (i.e., every 2 days). If pain and redness appear at the infusion site, the infusion set and site need to be changed immediately to prevent development of a skin infection.

Unexplained hyperglycemia. Unexplained hyperglycemia is a high blood glucose level that persists for more than 2-4 hours for no obvious reason. Usually the patient is not ill but performs a routine blood glucose test only to be surprised that the reading is in the 300-400 mg/dL range.

There are several potential causes of unexplained hyperglycemia, which, when present, requires a systematic investigation of the pump, syringe, infusion set, infusion site, and insulin vial to identify the cause. (See Table 6.) Since pump therapy uses only rapid-acting insulin, even a minor interruption of insulin delivery will result in hyperglycemia. Diabetic ketoacidosis (DKA) can occur in 4-6 hours after the insulin infusion is interrupted.15,45

As soon as the patient determines the presence of unexplained hyperglycemia, a bolus of insulin should be administered via the pump. The supplemental dose of insulin should be determined by the "1500 Rule,"14 which is used to determine an individual’s sensitivity to insulin. When properly calculated, the supplemental dose should return the blood glucose to the target blood glucose range. Two hours after administering the bolus, the blood glucose should be checked again. If the glucose remains high, an injection of insulin should be given using a regular insulin syringe. The infusion set should be changed, which should restore normal glycemic levels. However, if blood glucose remains high, the patient should discontinue CSII and initiate an emergency protocol during which routine insulin injections are administered every four hours based upon the blood glucose levels and carbohydrate counting at meal times.

If nausea or vomiting develops in the presence of unexplained hyperglycemia, a subcutaneous injection of insulin should be administered immediately. It is imperative for a pump user to understand that high blood glucose levels can lead to DKA and must be treated immediately. The cause of the high blood glucose must be treated subsequently.46

Weight gain. Weight gain has been associated with intensive insulin regimens. In the DCCT, subjects using intensive diabetes management gained an average of 5.1 kg over the whole study (average, 6.5 years per patient) compared with an average weight gain of 2.4 kg in conventionally treated subjects.47 The largest weight gain was associated with the greatest decreases in glycosylated hemoglobin levels and increased frequency of severe hypoglycemia. The weight gain occurred despite a reduction in caloric intake from baseline.

This weight gain, which occurs when blood glucose control is improved, is due to a reduction of caloric loss in the form of glycosuria. Frequent episodes of over-treatment of hypoglycemia may also be a factor. Weight reduction may be facilitated with CSII since patients do not need to eat as frequently or to eat between meal snacks, and can often skip meals without loss of glycemic control.22

Can a Pump Be Used during Pregnancy?

In no individual is excellent blood glucose control more important than in the pregnant diabetic patient.48 Hyperglycemia in pregnancy can result in congenital abnormalities including intrauterine growth delay, macrosomia, neonatal hypoglycemia, respiratory distress syndrome, and neonatal jaundice.29,49,50 The intrauterine mortality associated with DKA approaches 50%.51

CSII is best initiated before conception but can also be started during the pregnancy. The basal and bolus parameters will need to be updated frequently as the pregnancy progresses due to the accelerated catabolism, increasing insulin demand, and intensified production of counterregulatory hormones that oppose the actions of insulin during pregnancy. The target blood glucose levels during pregnancy are 70-110 mg/dL fasting and < 120 mg/dL two hours postprandially. Also, as the skin stretches during pregnancy, abdominal sites become less comfortable. Therefore, most pregnant pump users choose the upper arm or hip as the infusion site.

Special precautions and protocols must be used during pregnancy to prevent DKA. Due to the high rate of fetal mortality associated with DKA, a small supplemental bedtime dose of NPH or Lente insulin (0.2 u/kg) is recommended in addition to the normal or reduced nighttime basal rate.48 This NPH or Lente supplement reduces the likelihood that DKA will occur if the infusion of insulin is interrupted for any reason while sleeping.

What Types of Insulin Are Used?

Currently, only regular buffered insulin (Velosulin BR, Novo Nordisk, Princeton, NJ) is labeled for pump use. A new fast-acting insulin, insulin lispro (Humalog for injection) has been approved by the FDA and is now available for injection therapy. It is manufactured by Eli Lilly (Indianapolis, IN) and requires a doctor’s prescription. Insulin lispro is not yet labeled for use for pump therapy; however, tests using lispro in pumps are currently being conducted at three U.S. centers. Bench tests with pumps and infusion systems have demonstrated the stability of the insulin.52

In Canada, 30 Type I patients participated in a study using lispro and the pump.53 Both physician and participant were blinded as to whether they were taking lispro or regular insulin by pump for a three-month period. Participants were then "crossed over" to the alternate insulin for an additional three months. The authors reported significantly lower glycosylated hemoglobin (HbA1c) in the lispro group compared to the regular group (7.65% vs 7.99%; P = 0.0041) without an increase in the number of hypoglycemic episodes. Specific guidelines/algorithms for pump use are not expected until the results of the multi-center trial in the United States is completed. Studies (without the pump) have shown that the glucose-lowering action of lispro begins within five minutes of injection and that the duration of action is shorter.

Because insulin lispro has a shorter duration of action than regular insulin, it is more rapidly cleared from the body. Therefore, when it is approved for pump use, patients must be aware of the increased potential for more rapid onset of high blood glucose and diabetic ketoacidosis (DKA) if insulin delivery is interrupted. Extra attention should be given to self-monitoring of blood glucose and DKA prevention guidelines. In addition, it may be particularly important to adhere to the recommended infusion set change interval of every 2-3 days to be certain that interruption of flow does not occur.

Choosing Pump Therapy

The indications for CSII include the need for improved glycemic control and a patient’s desire to lead a more normal life, especially when daily schedules are erratic. Appropriate candidate selection is essential to the success of pump therapy. (See Table 7.)54 Pump therapy requires that patients possess certain physical, intellectual, and motivational abilities to ensure the optimum benefit and to reduce risks. Physical abilities are needed to accurately perform blood glucose monitoring and to carry out the technical components of insulin pump use. It is essential that a pump user understands the components of the pump regimen as well as troubleshooting the pump and infusion system if a problem should arise. The patient must be willing to comply with professional recommendations and to aggressively self-monitor blood glucose levels, to anticipate insulin needs for changing circumstances, and to make purposeful decisions and evaluate actions taken. Patients who take an active role in using pump therapy will have the best short- and long-term outcomes. When patients see the benefit of the increased effort, they are willing to work harder to achieve that goal.

Summary

Insulin pump therapy is an integral part of a complete intensive diabetes management program. As the number of patients being placed on CSII is increasing each year, physicians are often introduced to the pump when patients already using CSII are transferred to a new clinic. If the health care provider is unfamiliar with CSII, active participation in the patient’s daily pump management will enhance their ability to provide support and education for this intensively managed group of patients. Physicians must be knowledgeable in all aspects of intensive diabetes management in order to manage pump patients. Health care providers should attend professional pump programs where they may "mentor" and network with more experienced providers. Also, pump manufacturer representatives can provide instructional materials, operation manuals, tutorials, and videos to pump candidates and physicians.

As physicians and health care providers, we are challenged to design for the patient an insulin regimen that promotes both short- and long-term well-being. Each patient should have an individualized treatment regimen so that the patient’s potential for achieving optimal health and personal freedom is enhanced. Insulin pump therapy is an exciting option for the patient striving for improved diabetes self-care and a more normal lifestyle.

References

1. DCCT Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993;329:977-986.

2. LaPorte RE, et al. Prevalence and incidence of insulin-dependent diabetes. In: Diabetes in America, 2nd edition. Harris MI, et al (eds). National Institutes of Health; 1995:37.

3. Slama G, et al. One to five days of continuous intravenous insulin infusion on seven diabetic patients. Diabetes 1974; 23:732-738.

4. Hirsch IB, et al. Intensive insulin therapy for treatment of type I diabetes. Diabetes Care 1990;13:1265-1283.

5. DCCT Research Group. Implementation. Diabetes Care 1995.

6. Harris, et al. The DCCT and Medical Care for Diabetes in the U.S. Diabetes Care 1994;17:761-764.

7. Lauritzen T, et al. Pharmacokinetics of continuous subcutaneous insulin infusion. Diabetologia 1983;24:326-329.

8. Binder C, et al. Insulin pharmacokinetics. Diabetes Care 1984; 7:188-200.

9. Ronn B, et al. Evaluation of insulin pump treatment under routine conditions. Diabetes Res Clin Pract 1989;3:191-196.

10. Eichner HL, et al. Reduction of severe hypoglycemic events in type I (insulin-dependent) diabetic patients using continuous subcutaneous insulin infusion. Diabetes Res 1989;8:189-193.

11. Bell DSH, et al. The feasibility of long-term treatment of diabetes with continuous subcutaneous insulin infusion. Diab Nutr Metab 1993;6:57-60.

12. Hirsch IB, et al. Continuous subcutaneous insulin infusion for the treatment of diabetic patients with hypoglycemia unawareness. Diab Nutr Metab 1991;4:41-43.

13. Farkas-Hirsch R, Hirsch IB. Continuous subcutaneous insulin infusion: A review of the past and its implementation for the future. Diabetes Spectrum 1994;7:80-138.

14. Bode BW, et al. Reduction in severe hypoglycemia with long-term continuous subcutaneous insulin infusion in type I diabetes. Diabetes Care 1996;19:324-327.

15. Mecklenberg RS, et al. Acute complications associated with insulin infusion pump therapy. Report of experience with 161 patients. JAMA 1984;252:3265-3269.

16. Shapiro J, et al. Personality and family profiles of chronic insulin-dependent diabetic patients using portable insulin infusion pump therapy: A preliminary investigation. Diabetes Care 1984;7:137-142.

17. Pickup JC, et al. Continuous subcutaneous insulin infusion: An approach to achieving normoglycemia. BMJ 1978;1:204-207.

18. Tamborlane WV, et al. Reduction to normal of plasma glucose in juvenile diabetes by subcutaneous administration of insulin with a portable infusion pump. N Engl J Med 1979;300:573-578.

19. Skyler JS. Continuous subcutaneous insulin infusion (CSII) with external devices: Current status. In: Update in Drug Delivery Systems. Ensminger WD, Selam JL (eds). Mount Kisco, NY: Futura; 1989:163-183.

20. Bode BW. Establishing and verifying basal rates. In: The Insulin Pump Therapy Book: Insights from the Experts. Fredrickson L (ed). Sylmar, CA: MiniMed, Inc.; 1995:49-56.

21. Koivisto VA, et al. Pathogenesis and prevention of dawn phenomenon in diabetic patients treated with CSII. Diabetes 1985;35:78-82.

22. Strowig SM. Initiation and management of insulin pump therapy. Diabetes Educator 1993;18:50-59.

23. Davidson PC. Bolus and supplemental insulin. In: The Insulin Pump Therapy Book: Insights from the Experts. Fredrickson L (ed). Sylmar, CA: MiniMed; 1995:59-71.

24. American Diabetes Association. Position statement. Nutrition recommendations and principles for people with diabetes mellitus. Diabetes Care 1996;19:S16-S19.

25. Brackenridge BP. Carbohydrate gram counting: A key to accurate mealtime boluses in intensive therapy. Practical Diabetology 1992;11:22-28.

26. Hirsch IB, Polansky WH. Hypoglycemia and its prevention. In: The Insulin Pump Therapy Book: Insights from the Experts. Fredrickson L (ed). Sylmar, CA: MiniMed, Inc.; 1995:129-142.

27. American Diabetes Association. Insulin infusion pump therapy. In: Intensive Diabetes Management. Farkas-Hirsch R (ed). Alexandria, VA: American Diabetes Association; 1994:65-78.

28. Brackenridge BP, Reed JH. Counting carbohydrates: The key to proper bolusing. In: The Insulin Pump Therapy Book: Insights from the Experts. Fredrickson L (ed). Sylmar, CA: MiniMed, Inc.; 1995:73-83.

29. American Diabetes Association. Medical Management of Insulin-Dependent Type I Diabetes, 2nd ed. Santiago JV (ed). Alexandria, VA: American Diabetes Association; 1994:67-72.

30. American Diabetes Association. Therapy for Diabetes Mellitus and Related Disorders, 2nd ed. Lebonitz HE (ed). Alexandria, VA: American Diabetes Association; 1994;107-115.

31. Zinman B. Exercise and the pump. In: The Insulin Pump Therapy Book: Insights from the Experts. Fredrickson L (ed). Sylmar, CA: MiniMed, Inc.; 1995.

32. Unger J. Principles of intensive insulin therapy. Hospital Physician 1994;11:8-20.

33. Sonnenberg GE, et al. Exercise in type I (insulin-dependent) diabetic patients treated with continuous subcutaneous insulin infusion. Diabetologia 1990;33:696-703.

34. Campaigne BN, et al. Glucose and insulin response in relation to insulin dose and caloric intake 12 hours after acute physical exercise in men with IDDM. Diabetes Care 1987;10:716-721.

35. Walsh J, Roberts R. Insulin Pump Therapy Handbook. Sylmar, CA: MiniMed, Inc.; 1992:34.

36. DCCT Research Group. The effect of intensive treatment of diabetes on the development and progression of long-term complications in insulin-dependent diabetes mellitus. N Engl J Med 1993;329:977-986.

37. Cryer PE, et al. Hypoglycemia. Diabetes Care 1994;17:734-755.

38. Cryer PE. Hypoglycemia unawareness in IDDM. Diabetes Care 1993;16 (Suppl 3):40-47.

39. White NH. Hypoglycemia: A limiting factor in implementing intensive therapy. Clinical Diabetes 1994;12:101-105.

40. Fanelli CG, et al. Meticulous prevention of hypoglycemia normalizes the glycemic threshold and magnitude of most of neuroendocrine responses to, symptoms of, and cognitive function during hypoglycemia in intensively treated patients with short-term IDDM. Diabetes 1993;42:1683-1689.

41. Fanelli C, et al. Long-term recovery from unawareness, deficient counterregulation and lack of cognitive dysfunction during hypoglycemia, following institution of rational, intensive insulin therapy in IDDM. Diabetologia 1994;37:1265-1276.

42. Cryer PE. Hypoglycemia begets hypoglycemia in IDDM. Diabetes 1993;42:1691-1693.

43. Farkas-Hirsch R, Hirsch IB. Continuous subcutaneous insulin infusion: A review of the past and its implementation for the future. Diabetes Spectrum 1994;7:80-138.

44. Mecklenburg R. Acute complications associated with the use of insulin infusion pumps. Diab Educ 1989;15:40-43.

45. Bending JC, et al. Eight-month correction of hyperglycemia in insulin-dependent diabetes mellitus is associated with a significant and sustained reduction of urinary albumin excretion rates in patients with microalbuminuria. Diabetes 1985;34:69-73.

46. Fredrickson L. Insulin Pump Safety, Certified Pump Trainer Manual. Sylmar, CA: MiniMed, Inc.; 1996:65-75.

47. DCCT Research Group. Weight gain associated with intensive therapy in the Diabetes Control and Complications Trial. Diabetes Care 1988;11:567-573.

48. Marcus AO, Fernandez M. Insulin pump therapy; acceptable alternative to injection therapy. Postgraduate Med 1996;3:125-143.

49. Pedersen JF, Molsted-Pedersen L. Early growth retardation in diabetic pregnancy. In: Jovanovic L, et al (eds). Diabetes and Pregnancy, 1st ed. New York: Praeger; 1986.

50. Jovanovic L, et al. Effect of euglycemia on the outcome of pregnancy in insulin-dependent diabetic women as compared with normal control subjects. Am J Med 1981;71:921-927.

51. Kitzmiller JL. Diabetic ketoacidosis and pregnancy. In: Qaueenan JT (ed). Managing OB-Gyn Emergencies, 2nd ed. Oradell, NJ: Medical Economics; 1983:44-55.

52. Lougheed WD, et al. Chemical stability of insulin lispro in insulin infusion systems. Diabetes 1996;45:28A#1058.

53. Zinman B, et al. Insulin lispro in CSII: Results of a double-blind, crossover study. Diabetes 1996;45:28A#98.

54. Tanenberg RJ. Candidate selection. In: The Insulin Pump Therapy Book: Insights from the Experts. Fredrickson L (ed). Sylmar, CA: MiniMed, Inc.; 1995:21-30.

Physician CME Questions

6. When establishing the pump parameters of insulin dosage, the basal rate represents what percent of the total daily dose?

a. 15%

b. 25%

c. 35%

d. 50%

e. 65%

7. Using the "1500 Rule" for supplemental insulin, if an individual is taking 17 units of insulin per day, 1.0 unit of insulin will drop blood glucose approximately how many mg/dL?

a. 30

b. 40

c. 50

d. 90

e. 120

8. Skin infections are most commonly caused by :

a. Streptococcus.

b. Staphylococcus aureus.

c. Escherichia coli.

d. Candida albicans.

e. Listeria.

9. Hypoglycemia unawareness:

a. is a contraindication to pump therapy.

b. is an indication for pump therapy with modified glucose goals.

c. is related to the use of modified insulins such as NPH and Lente.

d. is caused by the pump.

e. is possible to overcome with self-medication.

10. To prevent DKA, what is the first action a pump user should take if blood glucose is unexplainably high and does not respond to a bolus via the pump?

a. Consume 15-25 grams of carbohydrate.

b. Determine the cause of the unexplained high BG.

c. Take an injection of regular insulin via syringe.

d. Check to see if the insulin has expired.

e. Exercise for 20 minutes.