of colors and materials (leather, vinyl, plastic, etc.)? Do case options include something like a “skin” used on cell phones to provide a grip and ease in holding the pump? Will the pump fit into a “universal” case, i.e., one that accommodates various pumps so that the patient may be able to purchase a case from another pump manufacturer?
• Is the pump available in more than one color? If not, can the user change the outside color or appearance of the pump?
• With what device can the pump communicate? Most insulin pumps can wirelessly communicate with either a blood glucose (BG) meter or a continuous glucose monitor (CGM). As of this writing, interconnectivity among all three devices is not yet available, but the integration of these technologies is on the horizon. Determine what is most important for the patient—the ease of wireless transmission of the BG from the meter to the pump for calculation of insulin doses, or use of a CGM device.
• What types of history does the pump store? Percentage of total daily dose (TDD) as basal and as bolus? Most recent boluses? A summary of daily delivery, including TDD, an average of TDD over X number of days, amounts of insulin delivered as correction boluses and meal boluses, infusion set changes? Total history, including alarms, alerts, battery changes, infusion set changes, and basal rate/pattern changes?
• Does the pump include software to download data reports of various types that can be used by both the patient and healthcare professional to track trends, make changes and corrections, and monitor overall use of the pump?
Insulin and insulin delivery
• What size is the cartridge/reservoir, i.e., how much insulin can it hold? Does the pump use a disposable cartridge/reservoir, or is the cartridge “built into” the pump? How much insulin can the cartridge/reservoir hold? This varies, and as of this writing ranges from 176 units to 315 units. This is important for people who are insulin resistant or use large doses of insulin. Remember that tubing connects the cartridge/reservoir to the infusion set and the tubing must be primed (filled) with insulin with each infusion set change (see Sets with tubing). A set change occurs every 24–72 hours, and the amount of insulin (approximately 20 to 45 units depending on the tubing length) changed/wasted (from discarding the tubing) should be taken into consideration. This may increase overall costs of the insulin supply. Overall, this is an important consideration in choosing a pump whose cartridge/reservoir contains <200 units for use in a patient requiring >55–60 units/day.
• Some pumps make noise during basal and bolus deliveries. The noise can be a “clicking” or “zzzz-sounding” type noise. Does this matter to the user?
• Frequent insulin delivery is an important issue for infants, toddlers, children, and insulin-sensitive adults. If the infusion set cannula or metal/steel needle is not infusing insulin constantly, subcutaneous or scar tissue may build up and occlude the site, impeding basal delivery. In contrast to pumps with solenoid motors, a direct-current motor pump delivers fractions of any basal rate, no matter how high or low, in “micro” pulses every 3 minutes. Insulin-sensitive patients are better matched to direct-current motor pumps.
Basal rate delivery
• Does the basal rate deliver in increments of 0.10 (tenth of a unit), 0.05 (twentieth of a unit), or 0.025 (fortieth of a unit)? Smaller increments are useful for fine-tuning basal rate delivery in children and insulin-sensitive people.
• Can the user temporarily increase and decrease basal rate delivery, and for how long? Can the pump be programmed to automatically calculate increases or decreases in percentages for several different basal rates, or can it alternately just calculate the number of units or units/hour? A temporary basal increase is helpful for acute illness or preceding menstruation, whereas a temporary decrease in basal delivery is useful for exercise.
• How many 24-h basal rate programs can be programmed into the pump? This is useful for patients who want to accommodate activity levels that vary day-to-day. For example, if weekend activity levels are different from weekday activity levels, the user may want to pre-set different 24-h basal programs with higher or lower rates instead of frequently resetting temporary basal rates. The ability to set alternate 24-h basal programs is a helpful feature for children who have gym class on specific days, adults who exercise on alternate days, and patients who are shift workers or weekend athletes, and is also useful for times of premenstrual syndrome, stress, and illness.
Bolus delivery
• What types of bolus delivery options does the pump have? Is the bolus delivery increment in twentieths, tenths, halves, or whole-unit increments, or does the user have a choice? Patients who are insulin sensitive may prefer or require fractional-unit bolus increments.
• Is there more than one type of bolus delivery available? An extended (“square wave”) or combination immediate/extended (“dual wave”) bolus delivery is useful for patients with gastroparesis and also may be used when consuming high-protein, high-fat, or ethnic meals and if using pramlintide. How long can delivery be extended? Can the delivery be in increments of an hour, such as 15, 30, or 45 minutes?
• Is there a touch bolus button? Is it audio or vibratory? This is a consideration for the patient who prefers to wear the pump discreetly and does not want to visibly press buttons on the pump or use a remote device to deliver a bolus.
• Is there a remote device available to deliver a bolus?
• Can specific bolus types be “named” and programmed into the pump for ease of use, such as “pizza,” “ethnic meal,” “dessert”? This is helpful and alleviates the need to repeatedly program a frequently used combination (“dual wave”) bolus.
• How is “insulin on board” (active insulin) calculated for bolus deliveries, i.e., can the user determine the number of hours the most recent bolus is active, or does the pump automatically default to a specific duration of time setting, such as 4 hours? This is a useful feature to prevent “insulin stacking” for repeated correction boluses (see Use of Duration of Insulin Action “Insulin on Board” or “Active Insulin” Feature). How does the insulin on board feature account for the insulin dose required for the upcoming meal?
• Does the pump store a history of bolus deliveries? How many? Can this information be downloaded to track trends and patterns of use and dosages?
Safety
• Can a bolus dose be stopped easily during delivery? Can the user track exactly how much of the bolus was delivered before it was halted?
• Is there a maximum use lockout feature for children, so that a basal rate or bolus delivery cannot be programmed for more than a specific upper limit?
• Is there a time-out feature that the user can pre-set to halt all insulin delivery if a button is not pushed for a specific duration of time?
• Can the user set an hourly limit of insulin delivery?
• What type of safety and performance checks does the pump have? How often does the pump perform self-checks?
• What types of warning and alarm systems does the pump have? Is there an alarm for undelivered basal insulin?
• Does the pump alarm sound/vibrate when insulin is running low or the cartridge/reservoir is empty? How is the amount indicated? Is it approximate or exact?
• If batteries are removed for an extended period of time, does the pump retain its memory of programmed basal rates and history
