Steve V. Edelman, MD
Robert R. Henry, MD
Patients can be taught how to analyze and use SMBG data to effectively make adjustments in their insulin doses so that they can maintain and improve glycemic control….
Insulin algorithms can be used with SMBG to make appropriate day-to-day changes in insulin dosing and to guide long-term treatment. The insulin algorithm shown in Figure 13.3 is used for patients receiving intensive insulin therapy. Self-adjustment guidelines for patients on a split-mixed regimen are shown in Table 13.4; insulin unit changes are provided by the physician on an individualized basis.
Over the past several years, home glucose monitoring devices have become smaller, faster, and easier to operate with data analysis capabilities. Computer generated data analysis can assist the care giver and the patient in many different areas, including data collection from blood glucose meters, certain insulin pumps, and other new devices. Computer software programs can also create charts and graphs that reveal trends and patterns in blood glucose values for easier evaluation by the patient and the caregiver. There are many software programs that are not only user-friendly for the patient, but are easy to read and analyze by the caregiver. Several programs can generate one-page summaries of a person’s diabetes monitoring data intended for optimal presentation of information. Information typically provided includes the standard day plot, before and after meals, pie graphs, the preceding 14 days in a combination graph format (where diet, exercise, and medication are shown with blood glucose levels) and a glucose line plot. The goal ranges and usual insulin doses are usually printed on the bottom of the page if applicable for that patient.
The fingerstick devices used to get a drop of blood for testing from the patient have improved with depth adjustable and sharp, thin lancets. There are meters that have the capability of getting blood from areas other than the fingertips, such as the forearm, for patient comfort and convenience. Other companies have developed bloodletting devices that can be used on the fingertips and other areas with special attachments to the finger sticker. Laser technology has also been designed to facilitate the bloodletting for these home devices.
SMBG is a fundamental part of diabetes management It is mandatory for tight glucose control. Intermittent measurement of capillary blood glucose via fingersticks has long been the method of choice for self-monitoring. However, such measurements provide isolated glucose values which do not reflect variations occurring throughout the day and night. In addition, this approach is dependent on patient education, diligence, and consistency. Hence systems monitoring blood glucose concentrations on a continuous basis have been developed. These devices allow for frequent and automatic glucose measurements, and thus can detect and track changes in glucose levels over time. This has tremendous implications for achieving near normalization of glucose control while avoiding the most serious complication of intensive glucose management, hypoglycemia. Several such devices are currently available.
The DexCom Seven with Open Choice (DexCom), Guardian Real-Time (Medtronic Diabetes), and the FreeStyle Navigator (Abbott Diabetes Care) are currently available and are composed of three basic parts: a sensor, a transmitter, and a receiver or monitor. The sensor, like a patch, is worn for up to 5 days and then replaced. It is placed just under the skin and is attached to a plastic sensor mount with adhesive to adhere to the skin. The small, unobtrusive transmitter snaps into the sensor mount and sends glucose information wirelessly to the pager-sized receiver, which can be worn on the belt or carried in a handbag. The sensor measures glucose every 1 to 5 minutes (frequency varies according to the device). The receiver displays the readings over time and provides high and low glucose level alarms that warn in advance when levels are trending toward hypoglycemic or hyperglycemic levels as determined the physician.
These systems also store up to 60 days of data, which can be analyzed by the patient or physician. Also available is the MiniMed Paradigm Real-Time System (Medtronic Diabetes), which is comprised of a sensor, transmitter, and insulin pump.
It is important to note that these systems measure interstitial glucose, a distinct physiologic space when compared with blood glucose. However, clinical trials with the various devices have shown there is an adequate correlation between interstitial and capillary blood glucose measurements. Nevertheless, the use of such systems adds information on PPG excursions, nocturnal hypoglycemia or hyperglycemia not previously detected by fingerstick monitoring, thereby facilitating the tailoring of treatment regimens for the individual patient. In addition, these devices are capable of communicating with implantable insulin pumps.
Totally noninvasive continuous glucose monitoring systems that utilize infrared technology are also under development.
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© Copyright 2010. Steven V. Edelman, MD, Robert R. Henry, MD, Professional Communications, Inc. All rights reserved.