guide the clinician in a practical manner to achieve a positive outcome. The most important guidelines for successful pump use in clinical practice begin with giving the patient—and those involved with the patient—-a clear understanding of what a pump is and is not. The pump is a device that enables more precise control over the amounts of insulin delivered and therefore how much insulin will be available at the cell receptor over time. It is not a cure for diabetes. Use of an insulin pump does not in and of itself constitute intensive therapy, which is defined by the targets and goals set for the levels of glucose. The pump itself does not demand more time and effort from the patient or the health-care team; it is the goal of achieving normal or improved glucose levels that calls for a commitment of time and effort from all involved. Pumps are a useful tool for insulin delivery when the goal is near-normal glycemia or ameliorating hypoglycemic events, in the treatment of hypoglycemic unawarcness. There is no age limit for pump usage—they have been used in people from 3 days old to over 80 years old. Pumps do allow for more choices and their success depends on the motivation, education, and involvement of all involved.
mination of bolus or basal rates before glucose measurement and assessment of insulin-delivery requirements is extremely arbitral}*; it should serve only as a place from which to start and then be further refined to match the needs of an individual person as those needs are discovered by observation arid interpretation. Commonly, patients going on CS1I or pump therapy require 20 to 25% less insulin than they did on injections (15-17).
Targets for glucose levels need to be set (Table 1). The most commonly used targets are those adopted by the American Diabetes Association and utilized in the DCCT (18): preprandial blood sugars of 70-140 mg/dl, 2-hour postprandial blood sugars of less than 180 mg/dl (with the clock starting when chewing begins), bedtime blood sugars of 100-140 mg/dl, and 3 a.m. blood sugars of greater than 90 mg/dl. Additional goals of glucose control recently set by the AACE consensus conference would seem to be appropriate. According to these, blood sugar levels would be a maximum of 110 mg/dl preprandial and 140 mg/ dl or less 2 hours postprandial (19). These targets are for patients who are not pregnant and who do not have hypoglycemic unawareness. Those conditions require different targets, which are discussed below.
Starting the pump is an outpatient procedure for the vast majority of patients. A certified pump trainer instructs the patient as to the various features and settings, which need to be in place before using the pump to deliver insulin. A method adopted successfully by most centers and offices is as follows. The patient takes his nighttime insulin the night before beginning to use the pump, and then begins pump therapy that morning prior to any meals. The initiation occurs in the office setting with the patient, others involved with the patient's care, and the physician or health-care provider all being present. The patient inserts the infusion set and is familiarized with such topics as basal rates and targets (Table
Table 2 Calculations of Adult Dosage
Basal rate 50% of pump total daily dose
Divide total bas8l by 24 hours to decide on hourly basal
Start with only one basal rate
See how it goes before adding additional basals
Basal rate adjustment overnight Check 8G Bedtime
Adjust overnight basal if readings vary >30 mg/dl
Correction bolus—rule of 1500a Insulin sensitivity factor
Determines the estimated BG drop per unit of insulin
Estimating an insulin-to-carbohydrate ratio—rule of 500 (500 divided by TDD)
Example: 500/50 = 10 = 1 unit of insulin per 10 g carbohydrate
2). Written guidelines are provided on these as well as for the administration of insulin as pre-mea), correction boluses, and basals, with instructions for adapting these initial calculations as necessary. Follow-up is usually scheduled for the next day, once again the following week, and then as often as deemed appropriate.
Initially only one basal rate is set for a 24-hour period. This rate is verified by the patient's checking at 2- or 3-hour intervals for a total of 6 hours, without food or food boluses being taken during this time. If the blood sugar level does not change by more than 30 mg/dl from beginning to end, the basal rate is confirmed as correct. When the glucose level changes in excess of 30 mg/dl, differing basal rates can be added. The newer and original basal rates are changed to accommodate the varying physiological need for insulin during these lime periods -g (e.g., if at 10:00 a.m. blood sugar is 90 and at 12:00, 2 hours later, it is 140, die h basal rate is increased over this period by 0.1 or 0.2 units per hour). Any change ^ in insulin should be reconfirmed the following day. The "dawn phenomenon," a sudden increase in glucose prior to awakening, requires an increase in the 5 amount of insulin being pumped or delivered at the time the glucose level is J rising; in such cases, blood sugar readings should be taken at midnight, 3 a.m., jj and 6 a.m. Again, changes in blood sugar by more than 30 mg/dl from the begin- o
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...