Evaluation of a continuous glucose monitoring system in diabetic dogs

The generation of a blood glucose curve is important for assessing the response to insulin therapy in diabetic dogs. Disadvantages of this technique include patient discomfort and the potential for missing transient hypo- or hyperglycaemic episodes. The aim of the current study was to evaluate a continuous glucose monitoring system (CGMS) for use in diabetic dogs. Interstitial fluid glucose concentrations were recorded in 10 diabetic dogs, every five minutes for up to 48 hours, using a subcutaneous sensor attached to the CGMS device. Blood glucose concentrations were measured simultaneously using a glucometer. The correlation between interstitial fluid and blood glucose values was 0.81 (P < 0.01). The largest discrepancies between the two sets of data were seen during the one- to three-hour period following feeding, suggesting that postprandial hyperglycaemia might not be reflected in the interstitial fluid. The authors conclude that the CGMS is a potentially valuable tool in the management of canine diabetic patients.     

Continuous glucose monitoring in dogs and cats

Use of continuous glucose monitoring in veterinary medicine is gaining popularity. Through use of a commercially available continuous glucose monitor system, insights into daily glucose changes in dogs and cats are achievable. The continuous glucose monitoring system measures glucose concentrations in the interstitial fluid of the subcutaneous space by use of a small, flexible probe. When placed in the subcutaneous tissue, the probe is connected to a recording device that is attached to the animal and records the interstitial fluid glucose concentration every 5 minutes (288 readings per 24 hours). Once attached and properly calibrated, the instrument can remain in place for several days, hospitalization of the patient is not necessary, and the normal daily routine of the animal can be maintained. The data from the recording device are then downloaded and a very detailed picture of the interstitial fluid glucose concentration over that time period can be obtained. Subcutaneous interstitial fluid glucose concentrations have a good correlation to blood glucose concentrations within a defined range. The continuous glucose monitoring system has distinct advantages over traditional blood glucose curves and is a valuable tool for managing diabetic dogs and cats. In addition, other clinical uses for continuous glucose monitoring are being developed. This review is designed to outline the technology behind the continuous glucose monitoring system, describe the clinical use of the instrument, provide clinical examples in which it may be useful, and discuss future directions for continuous glucose monitoring in dogs and cats.     

Clinical assessment of blood glucose homeostasis in horses: comparison of a continuous glucose monitoring system with a combined intravenous glucose and insulin test protocol

Background: The combined glucose‐insulin test (CGIT) is helpful for evaluating insulin sensitivity. A continuous glucose monitoring system (CGMS) reports changes in interstitial glucose concentrations as they occur in the blood. Use of the CGMS minimizes animal contact and may be useful when performing a CGIT. Hypothesis: Results obtained using a CGMS are useful for the evaluation of glucose responses during the evaluation of insulin sensitivity in equids. Animals: Seven mature, obese ponies. Methods: Ponies were equipped with CGMS for determination of interstitial glucose concentrations. Glucose (150 mg/kg, IV) and insulin (0.1 U/kg, IV) were administered and blood glucose concentrations determined at (minutes after time zero) 1, 5, 15, 25, 35, 45, 60, 75, 90, 105, and 120 with a hand‐held glucometer. Blood chemistry results were compared with simultaneously obtained results using CGMS. Results: Concordance coefficients determined for comparison of blood glucose concentrations determined by a hand‐held glucometer and those determined by CGMS after the zero time point were 0.623, 0.764, 0.834, 0.854, and 0.818 (for delays of 0, 5, 10, 15, and 20 minutes, respectively). Conclusions and Clinical Importance: Interstitial glucose concentrations obtained by the CGMS compared favorably to blood glucose concentrations. CGMS may be useful for assessment of glucose dynamics in the CGIT.     

Evaluation of a continuous glucose monitoring system in cats with diabetes mellitus

A continuous glucose monitoring system (CGMS) was evaluated in 14 cats with naturally occurring diabetes mellitus. The device measures interstitial fluid glucose continuously, by means of a sensor placed in the subcutaneous tissue. All cats tolerated the device well and a trace was obtained on 15/16 occasions. There was good correlation between the CGMS values and blood glucose concentration measured using a glucometer (r=0.932, P<0.01). Limitations to the use of the CGMS are its working glucose range of 2.2-22.2 mmol/l (40-400 mg/dl) and the need for calibration with a blood glucose measurement at least every 12 h. When compared to a traditional blood glucose curve, the CGMS is minimally invasive, reduces the number of venepunctures necessary to assess the kinetics of insulin therapy in a patient and provides a truly continuous glucose curve.     

Portable blood glucose meters as a means of monitoring blood glucose concentrations in dogs and cats with diabetes mellitus

The use of portable blood glucose meters (PBGM) has become common in veterinary medicine as a rapid means of monitoring animals' blood glucose in a variety of medical conditions. These hand-held monitors allow for diagnostic and therapeutic decisions to be made quickly and relatively inexpensively using only a small amount of blood. Both in conditions resulting in hyperglycemia, such as diabetes mellitus, and in those resulting in hypoglycemia, such as sepsis or the presence of an insulinoma, veterinarians have come to rely on PBGM to provide critical information on the status of their animal patients. In particular, PBGM are frequently used to measure individual blood glucose values in an animal over a period to create a blood glucose curve when evaluating the effectiveness of insulin therapy in diabetic dogs and cats.     

Accuracy of a continuous glucose monitoring system in dogs and cats with diabetic ketoacidosis

Objective – (1) To determine the ability of a continuous interstitial glucose monitoring system (CGMS) to accurately estimate blood glucose (BG) in dogs and cats with diabetic ketoacidosis. (2) To determine the effect of perfusion, hydration, body condition score, severity of ketosis, and frequency of calibration on the accuracy of the CGMS. Design – Prospective study. Setting – University Teaching Hospital. Animals – Thirteen dogs and 11 cats diagnosed with diabetic ketoacidosis were enrolled in the study within 24 hours of presentation. Interventions – Once BG dropped below 22.2 mmol/L (400 mg/dL), a sterile flexible glucose sensor was placed aseptically in the interstitial space and attached to the continuous glucose monitoring device for estimation of the interstitial glucose every 5 minutes. Measurements and Main Results – BG measurements were taken with a portable BG meter every 2–4 hours at the discretion of the primary clinician and compared with CGMS glucose measurements. The CGMS estimates of BG and BG measured on the glucometer were strongly associated regardless of calibration frequency (calibration every 8 h: r=0.86, P<0.001; calibration every 12 h: r=0.85, P<0.001). Evaluation of this data using both the Clarke and Consensus error grids showed that 96.7% and 99% of the CGMS readings, respectively, were deemed clinically acceptable (Zones A and B errors). Interpatient variability in the accuracy of the CGMS glucose measurements was found but was not associated with body condition, perfusion, or degree of ketosis. A weak association between hydration status of the patient as assessed with the visual analog scale and absolute percent error (Spearman's rank correlation, ρ=?0.079, 95% CI=?0.15 to ?0.01, P=0.03) was found, with the device being more accurate in the more hydrated patients. Conclusions – The CGMS provides clinically accurate estimates of BG in patients with diabetic ketoacidosis.     

Home-based subcutaneous continuous glucose monitoring in 10 diabetic dogs

A subcutaneous continuous glucose monitoring system (GlucoDay; Menarini Diagnostics) based on microdialysis was investigated for its clinical applicability in veterinary medicine. Ten diabetic dogs, referred as clinically stable, were equipped with this system and sent home for a maximum observation period of 48 hours. Time of insulin administration, feeding and other events were written in a diary and plotted afterwards in the glucose graph. Implantation of the microdialysis fibre, acceptance of the device and evaluation of individual canine glucose profiles were without complication. Based on the monitoring data, recommended treatment adjustments were given to the referring veterinarians in all 10 dogs; hypoglycaemic or prolonged hyperglycaemic episodes were detected in six dogs.     

Field method for monitoring blood glucose in beef cattle.

The purpose of this study was to determine the applicability of the Accu-Chek Easy (ACE) human self-monitoring system for monitoring glycemic status in cattle. The ACE method was compared with the Yellow Springs Instrument (YSI) analytical laboratory method in two studies. A preliminary study (62 samples) and a primary study (434 samples) involved a nine-fold range and a 10-fold range, respectively, of glucose concentrations obtained during the acute phase response of growing beef cattle to injections of varying dosages of endotoxin. The ACE monitoring method compared with the YSI analytical method resulted in similar patterns of glucose concentration change, similar ranking of glucose means across endotoxin dosages during hyper-and hypoglycemia, and a close relationship between paired YSI and ACE concentrations from common samples. The ACE method identified all nine animals that displayed hypoglycemic distress during the acute phase response to endotoxin injection. The relationship between the YSI analytical method and the ACE monitoring method was found to be nonlinear (YSI = -38.2+13.6.ACE.50; R2 = .99; Sy.x = 7.3 mg/dL), and the use of this equation to predict YSI values from ACE values in an independent data set resulted in linearity when YSI was regressed on the predicted YSI values (YSI = -.78+1.00.Predicted YSI; R2 = .87; Sy.x = 6.9 mg/dL). Even though variation seemed greater for ACE than for YSI, we concluded that a system developed for human self-monitoring of blood glucose, such as the ACE, can be used to monitor the glycemic status of cattle.     

Evaluation of a continuous glucose monitoring system for use in dogs, cats, and horses

OBJECTIVE: To evaluate a continuous glucose monitoring system (CGMS) for use in dogs, cats, and horses. DESIGN: Prospective clinical study. Animals-7 horses, 3 cats, and 4 dogs that were clinically normal and 1 horse, 2 cats, and 3 dogs with diabetes mellitus. PROCEDURE: Interstitial glucose concentrations were monitored and recorded every 5 minutes by use of a CGMS. Interstitial glucose concentrations were compared with whole blood glucose concentrations as determined by a point-of-care glucose meter. Interstitial glucose concentrations were also monitored in 2 clinically normal horses after oral and i.v. administration of glucose. RESULTS: There was a positive correlation between interstitial and whole blood glucose concentrations for clinically normal dogs, cats, and horses and those with diabetes mellitus. Events such as feeding, glucose or insulin administration, restraint, and transport to the clinic were recorded by the owner or clinician and could be identified on the graph and associated with time of occurrence. CONCLUSIONS AND CLINICAL RELEVANCE: Our data indicate that use of CGMS is valid for dogs, cats, and horses. This system alleviated the need for multiple blood samples and the stress associated with obtaining those samples. Because hospitalization was not required, information obtained from the CGMS provided a more accurate assessment of the animal's glucose concentrations for an extended period, compared with measurement of blood glucose concentrations. Use of the CGMS will promote the diagnostic and research potential of serial glucose monitoring.     

Home monitoring of blood glucose concentration by owners of diabetic dogs

The objective of this study was to investigate whether home monitoring of blood glucose of diabetic dogs by owners would be possible on a long-term basis. The owners of 12 diabetic dogs were each asked to generate four glucose curves by taking capillary blood samples from their dog's ear, at three- to four-week intervals. Within one week of each curve being produced by the owner, an additional curve was produced by a veterinarian in the hospital. Ten owners were able to generate blood glucose curves; three of them needed a second demonstration, and two telephoned for further guidance. The blood glucose concentrations obtained from the first two 'hospital' curves were significantly lower than those measured at home. Overall, in 42 per cent of cases, the treatment based on the hospital curves would have been different from that based on 'home' curves. The results of this study indicate that the majority of owners were able and willing to perform long-term monitoring of the blood glucose concentrations of their dogs.     

Home monitoring of blood glucose concentrations by owners of diabetic dogs and cats

Generation of blood glucose curves is essential to monitor glycemic control in dogs and cats with diabetes mellitus. Up till now blood collection and blood glucose measurements could only be performed in a hospital. However, glucose concentrations measured in a hospital environment can markedly differ from concentrations measured at home, due to reduced appetite, different activity level and stressful handling. At the Clinic of Small Animal Internal Medicine, University of Zurich, a new method to collect capillary blood from the ear and to measure blood glucose by means of a portable glucose meter has been developed. This method enables owners of diabetic dogs or cats to determine blood glucose concentrations and generate blood glucose curves at home. Three cases demonstrate, how much blood glucose concentrations at home may differ from those in the hospital and how home monitoring can help to establish diabetic control in dogs and cats.     

Retrospective study of owners' perception on home monitoring of blood glucose in diabetic dogs and cats

Home monitoring of blood glucose (HMBG) concentrations has been recommended in the monitoring of human diabetics for 3 decades. During the last number of years, it also gained popularity in long-term follow-up of diabetic cats and dogs. The aim of this retrospective study was to evaluate the practical feasibility of and identify the major problems encountered with HMBG in diabetic pets. A standard questionnaire was filled in by owners of 9 diabetic pets monitored with HMBG. The need for more than 1 puncture to obtain a blood drop, the creation of a sufficient blood drop, the need for assistance in restraining the pet, and the resistance of the pet were the most frequently encountered problems during HMBG. The major obstacles for the owners to start with HMBG were also identified. In conclusion, HMBG is a practical and simple technique for most owners and, overall, owners were satisfied.