Traditional methods of blood glucose monitoring involve obtaining samples for measurement via laboratory methodology or point of care devices and require invasive collection techniques such as capillary stick, venipuncture, or the placement of intravenous catheters. Limitations of traditional methods include the limited information provided by intermittent testing and the stress associated with restraint and discomfort experienced by patients. The snapshot nature of the provided information restricts a clinician's ability to truly monitor trends in glucose concentrations over an extended period of time, influencing clinical decision making. The stress of invasive sampling can cause stress hyperglycemia in many veterinary species, complicating interpretation. Continuous interstitial glucose monitoring technology is widely used in the human medical field due to the expansive information provided in a minimally invasive manner. In recent years, the device technology has advanced and cost has improved, prompting application of these devices into the veterinary sector. Studies have shown good agreement between newer glucose monitoring systems and traditional methods in small animal patients with diabetes mellitus, allowing veterinarians to obtain comprehensive glucose data with minimal stress and discomfort to the patient. However, information regarding the use of this new technology in equine medicine is limited. The following study describes the evaluation of two widely available glucose monitoring systems, the Dexcom G6 and the FreeStyle Libre, in healthy adult horses. / Master of Science / Monitoring of glucose concentrations is essential for the diagnosis and monitoring of a variety of disorders within equine medicine. Traditional methods of obtaining samples for testing include capillary stick, venipuncture, or the placement of intravenous catheters, which can cause stress and discomfort to equine patients. The information obtained by this testing methodology only allows for intermittent assessment of glucose concentrations, limiting the amount of information available for clinicians to make clinical decisions. The use of continuous glucose monitoring systems in the human medical field have allowed clinicians to obtain continuous or near-continuous glucose concentrations, improving interpretation. These devices have nearly eliminated the need for blood sampling for glucose concentrations, instead relying on interstitial glucose concentrations which have been shown to compare favorably to blood concentrations. Studies in small animal veterinary species, such as dogs and cats, have shown good agreement between newer glucose monitoring systems and traditional methods in small animal patients with diabetes mellitus, allowing veterinarians to obtain comprehensive glucose data with minimal stress and discomfort to the patient. However, information regarding the use of this new technology in horses is limited. The study described in the manuscript following evaluates the use of two widely available glucose monitoring systems, the Dexcom G6 and the FreeStyle Libre, in healthy adult horse.

INTRODUCTION: Type 1 diabetes (T1D) is a lifelong disease that requires regular injection of insulin and blood glucose (BG) monitoring. Many diabetes technologies have been created to assist in the management of T1D, including insulin pumps and Continuous Glucose Monitoring (CGM). These systems have been shown to decrease treatment distress and improve glycemic control. However, the uptake of these systems is low due to both cost and other barriers such as discomfort of wear or psychosocial aspects. METHODS: A survey was administered to clinicians of people with diabetes to better understand their perception of patient related barriers to device use. This analysis compares two clusters of clinicians, named "Cautious" and "Ready" based on their readiness to promote CGM use in their patients. Both have positive attitudes towards technology, but the Cautious cluster perceives much higher barriers to device use in their patients than the Ready cluster. In this analysis, the individual barriers, prerequisites to CGM use, confidence in addressing barriers, and clinic staff resources are compared between clusters using independent means t-tests and Pearson chi-square analyses. RESULTS: Results indicate that the confidence in addressing the clinician-reported number 1 rated barrier to CGM use was significantly lower in the Cautious cluster. Also, most individual barriers were perceived significantly more heavily by clinicians in the Cautious cluster. No significant difference was found in prerequisites to CGM use or clinic staff resources between the clusters. DISCUSSION: Because no differences were found in clinician reported prerequisites to CGM use between clusters, it does not seem that the clinicians in the Cautious cluster expect more from their patients before using this technology. One possible explanation would be a clinical deficiency. However, since there was no difference in clinic staff resources, it is unlikely that the availability of these resources contributes to the increased perceived barriers. Thus, the problem may lie in the clinician themselves. One possible explanation for the increased perceived barriers by the Cautious cluster is their lack of confidence in addressing barriers. Our results show that the Cautious cluster is significantly less confident in addressing the #1 barrier their patients face to CGM use, which is most commonly listed as cost-related barriers such as cost of the device or insurance status. One possible solution to this lack of confidence in clinicians is increased education on ways to address and coach patients on cost-related barriers.

The ability to measure glucose transcutaneously and noninvasively is an exciting prospect. Such a procedure will offer a painless way of glucose self-monitoring improving the lives of people with diabetes by lowering the barriers to optimal glycemic control. The noninvasive measurements involve collecting near-infrared spectra (4000–5000 cm-1; 2.0–2.5 µm) of skin with two optical fibers in a transmission geometry. Previous results indicate that repositioning of the fiber optic interface adversely affects both precision and accuracy of such measurements. Slight movements of the interface increase prediction errors more than 2.5–fold when performed with a stationary rat model. In this dissertation, the chemical heterogeneity of skin tissue is explored as a possible cause for the sensitivity of the measurement to the position of the optical interface. Rat and human skin tissues are mapped by using combination near infrared spectra the to provide distributions of the major components of skin: water, collagen type I protein, fat, keratin protein, and two scattering terms of constant and slope. On the basis of the measured heterogeneity, sets of rat and human skin spectra are simulated to investigate the impact of repositioning the fiber-optic interface. Glucose predictions are analyzed for each location of the interface for a series of partial least squares (PLS) calibration vectors established for different locations on the skin. Significant increases in the measurement errors are observed for the situation where the PLS calibration models are generated from spectra associated with one location of the interface while subsequent measurements are performed at slightly locations of the skin matrix. These increases in prediction errors match the 2.5–fold increase observed in vivo. The impact of replacing the spectrum of bovine fat with spectra of native fat for both rat and human skin samples is established. Principal component analysis (PCA) of the spectral residuals reveals that the magnitude of the spectral residuals and the effects of tissue fat content on the quality of the linear regression were decreased. The key implication of the research detailed in this dissertation is that chemical heterogeneity of skin tissue must be considered in multivariate models intended for noninvasive glucose measurements.

No description available.

Introduction: Brief vigorous exercise can enhance glycemic control. Limited work has investigated the effect of simple, practical interventions that require no specialized equipment. We examined the effect of bodyweight exercise (BWE) on acute glycemic control using continuous glucose monitoring (Abbott Libre Sense) under controlled dietary conditions This study was registered as a clinical trial (NCT05144490). Methods: Twenty-seven healthy adults (8 males, 19 females; age: 23±3 y) completed two virtually supervised trials in random order ~1 wk apart. The trials involved an 11-min BWE protocol that consisted of five, 1-min bouts performed at a self-selected pace interspersed with 1-min active recovery periods or a non-exercise sitting control period (CON). Food intake was standardized for each participant using pre-packaged meals supplied over 24 h. Results: Mean rating of perceived exertion for BWE was 14±2 (6-20 scale). Mean HR over the 11-minute the BWE protocol was 147±14 bpm which corresponded to 75% of age-predicted maximal HR. Mean 24-h glucose after BWE and CON was not different (5.0±0.4 vs 5.0±0.5 mM respectively; p=0.39). Postprandial glucose responses were also not different between trials after ingestion of a 75 g glucose drink, lunch, dinner and breakfast meals after each intervention. Measures of glycemic variability were not different between conditions. Conclusion: A single session of BWE did not alter acute glycemic control in healthy, young adults. This study demonstrates the feasibility of conducting a remotely supervised BWE intervention using CGM under free-living conditions. Future studies should investigate the effect of repeated sessions of BWE training as well as responses in people with impaired glycemic control. / Thesis / Master of Science (MSc) / We investigated the effect of brief bodyweight exercise (BWE) on glycemic control. This refers to the ability to maintain blood sugar within a healthy range. Glycemic control was assessed with a small device called a continuous glucose monitor (CGM) that is inserted just below the skin. Healthy adults completed a virtually supervised 11-minute BWE protocol or an equivalent period of sitting. There was no difference in glycemic control measured over 24 hours following the BWE compared to sitting under standardized dietary conditions. Future studies should investigate the effect of repeated sessions of BWE training as well as responses in people with impaired glycemic control.

Physical activity is important for the management and treatment of type 2 diabetes (T2D). Interval exercise training has been shown to improve glycemic control in people with T2D; however, studies have generally utilized high volume protocols and/or specialized equipment that limit translation to a “real world” setting. The present proof-of-concept study examined the efficacy of brief, intermittent stair climbing exercise to improve indices of glycemic control in adults with T2D, using continuous glucose monitoring (CGM) under controlled dietary conditions. Each session involved 3 x 60-s bouts of vigorously ascending and slowly descending a single flight of stairs. This was set within a 10-min period, which otherwise involved walking for a warm-up, cool-down and recovery in between bouts. Data are reported for n=5 participants (52 ± 18 y, BMI: 31 ± 5 kg/m2, HbA1c: 6.6 ± 0.7 %; mean ± SD) who performed 18 training sessions over 6 weeks. Mean 24-h glucose and time spent in hyperglycemia (> 10 mmol/L) were unchanged after an acute session of stair climbing (p=0.38 and p=0.42, respectively) or after 6 weeks of training (p=0.15 and p=0.47, respectively). Measures of glycemic variability were improved in the 24-h period following a single session of stair climbing, based on reductions in the mean amplitude of glycemic excursions (MAGE) (4.4 ± 1.5 vs. 3.5 ± 1.0 mmol/L, p =0.02) and the standard deviation (SD) around the mean (1.7 ± 0.5 vs. 1.4 ± 0.5 mmol/L, p=0.02). There was a meal-specific improvement in postprandial hyperglycemia after training, with the incremental area under the curve (iAUC) of the lunchtime meal reduced by 36 ± 42 % (p=0.01). These preliminary results demonstrate the feasibility of stair climbing as a physical activity option for people with T2D, although the acute and chronic effects of this training on indices of glycemic control remain equivocal. / Thesis / Master of Science in Kinesiology / Physical activity is important for the management of type 2 diabetes (T2D). Interval training, which involves alternating periods of relatively intense exercise and recovery, can improve blood sugar control in adults with T2D. This has largely been shown in laboratory settings using specialized equipment and protocols that may not be practical or time-efficient. This small, proof-of-concept study examined whether brief, intermittent stair climbing exercise could improve blood sugar control in people with T2D. Average blood sugar measured over 24 hours was unchanged after a single bout of stair climbing and after 18 sessions of training performed over 6 weeks. However, stair-climbing exercise reduced blood sugar fluctuations in response to specific meals. These preliminary findings suggest that interval stair climbing is a feasible exercise option for adults with T2D, but the precise effects on blood sugar control remain to be clarified.

Critically ill patients often exhibit abnormal glycaemia that can lead to severe complications and potentially death. In critically ill adults, hyperglycaemia is a common problem that has been associated with increased morbidity and mortality. In contrast, critically ill infants often suffer from hypoglycaemia, which may cause seizures and permanent brain injury. Further complicating the matter, both of these conditions are diagnosed by blood glucose (BG) measurements, often taken several hours apart, and, as a result, these conditions can remain poorly managed or go completely undetected. Emerging ‘continuous’ glucose monitoring (CGM) devices with 1-5 minute measurement intervals have the potential to resolve many issues associated with conventional intermittent BG monitoring. The objective of this research was to investigate and develop methods and models to optimise the clinical use of CGM devices in critically ill patients. For critically ill adults, an in-silico study was conducted to quantify the potential benefits of introducing CGM devices into the intensive care unit (ICU). Mathematical models of CGM error characteristics were implemented with existing, clinically validated, models of the insulin-glucose regulatory system, to simulate the behaviour of CGM devices in critically ill patients. An alarm algorithm was also incorporated to provide a warning at the onset of predicted hypoglycaemia, allowing a virtual dextrose intervention to be administered as a preventative measure. The results of the in-silico study showed a potential reduction in nurse workload of approximately 75% and a significant reduction in hypoglycaemia, while also providing insight into the optimal rescue dose size and resulting dynamics of glucose recovery. During 2012, ten patients were recruited into a pilot clinical trial of CGM devices in critical care with a primary goal of assessing the reliability of CGM devices in this environment, with a specific interest in the effects of CGM device type and sensor site on sensor glucose (SG) data. Results showed the mean absolute relative difference of SG data across the cohort was between 12-24% and CGM devices were capable of monitoring some patients with a high degree of accuracy. However, certain illnesses, drugs and therapies can potentially affect sensor performance, and one particular set of results suggested severe oedema may have affected sensor performance. A novel and first of its kind metric, the Trend Compass was developed and used to assesses trend accuracy of SG in a mathematically precise fashion without approximation, and, importantly, does so independent of glucose level or sensor bias, unlike any other such metrics. In this analysis, the trend accuracy between CGM devices was typically good. A recent hypothesis suggesting that glucose complexity is associated with mortality was also investigated using the clinical CGM data. The results showed that complexity results from detrended fluctuation analysis (DFA) were influenced far more by CGM device type than patient outcome. In addition, the location of CGM sensors had no significant effect on complexity results in this data set. Thus, while this emerging analytical method has shown positive results in the literature, this analysis indicates that those results may be misleading given the impact of technology outweighing that of physiology. This particular result helps to further delineate the range of potential applications and insight that CGM devices might offer in this clinical scenario. In critically ill infants, CGM devices were used to investigate hypoglycaemia during the first 48 hours after birth. More than 50 CGM data sets were obtained from several studies of CGM in infants at risk of hypoglycaemia at the Waikato hospital neonatal ICU (NICU). In light of concerns regarding CGM accuracy, particularly during the first few hours of monitoring and/or at low BG levels, an alternative, novel calibration scheme was developed to increase the reliability of SG data. The recalibration algorithm maximised the value of very accurate calibration BG measurements from a blood gas analyser (BGA), by forcing SG data to pass through these calibration BG measurements. Recalibration increased all metrics of hypoglycaemia (number, duration, severity and hypoglycaemic index) as the factory CGM calibration was found to be reporting higher values at low BG levels due to its least squares calibration approach based on the assumption of a less accurate calibration glucose meter. Thus, this research defined new calibration methods to directly optimise the use of CGM devices in this clinical environment, where accurate reference BG measurements are available. Furthermore, this work showed that metrics such as duration or area under curve were far more robust to error than the typically used counted-incidence metrics, indicating how clinical assessment may have to change when using these devices. The impact of errors in calibration measurements on metrics used to classify hypoglycaemia was also assessed. Across the cohort, measurement error, particularly measurement bias, had a larger effect on hypoglycaemia metrics than delays in entering calibration measurements. However, for patients with highly variable glycaemia, timing error can have a significantly larger impact on output SG data than measurement error. Unusual episodes of hypoglycaemia could be successfully identified using a stochastic model, based on kernel density estimation, providing another level of information to aid decision making when assessing hypoglycaemia. Using the developed algorithms/tools, with CGM data from 161 infants, the incidence of hypoglycaemia was assessed and compared to results determined using BG measurements alone. Results from BG measurements showed that ~17% of BG measurements identified hypoglycaemia and over 80% of episodes occurred in the first day after birth. However, with concurrent BG and SG data available, the SG data consistently identified hypoglycaemia at a higher rate suggesting the BG measurements were not capturing some episodes. Duration of hypoglycaemia in SG data varied from 0-10+%, but was typically in the range 4-6%. Hypoglycaemia occurred most frequently on the first day after birth and an optimal measurement protocol for at risk infants would likely involve CGM for the first week after birth with frequent intermittent BG measurements for the first day. Overall, CGM devices have the potential to increase the understanding of certain glycaemic abnormalities and aid in the diagnosis/treatment of other conditions in critically ill patients. This research has used a range of prospective and retrospective clinical studies to develop methods to further optimise the use of CGM devices within the critically ill clinical environment, as well as delineating where they are less useful or less robust. These latter results clearly define areas where clinical practice needs to adapt when using these devices, as well as areas where device makers could target technological improvements for best effect. Although further investigations are required before these devices are regularly implemented in day-to-day clinical practice, as an observational tool they are capable of providing useful information that is not currently available with conventional intermittent BG monitoring.

Trata-se de uma pesquisa de avaliação, realizada por análise de resultados antes e após uma intervenção, cujo objetivo principal foi avaliar a contribuição de um programa educativo na monitorização da glicemia capilar, em pessoas com diabetes mellitus tipo 2. A amostra ficou constituída por 82 pessoas, em seguimento ambulatorial em um hospital de atenção terciária do interior paulista. As intervenções educativas foram desenvolvidas em grupo aberto, por meio da ferramenta \"Mapas de Conversação em Diabetes\", fundamentada nos pressupostos da Teoria Social Cognitiva. O programa educativo se desenvolveu em quatro sessões, com duração média de uma hora e quinze minutos para cada tema, respectivamente: fisiopatologia, controle e complicações da doença, alimentação e atividade física, medicamentos e monitorização da glicemia capilar e da insulina. Além destas sessões, ocorreram dois encontros adicionais para a coleta dos dados, o primeiro antes das intervenções e o segundo, após o seu término. No terceiro encontro, enfatizaram-se os cuidados com a monitorização da glicemia capilar, e foram entregues glicosímetros e insumos para a avaliação da glicemia capilar no domicílio. Para a caracterização da amostra, utilizou-se a estatística descritiva, e para as análises dos dados utilizaram-se os testes de McNemar, para as variáveis categóricas, os Testes de Wilcoxon e o de Correlação de Spearman, mediante nível de significância de 5% (alfa = 0,05). Na caracterização da amostra, destacam-se: 48(58,54%) são do sexo feminino, e os respectivos valores médios da idade são 60,4(DP=8,4) anos; dos anos estudados 4,86(DP=3,86) anos e do diagnóstico da doença 15,3 (DP=8,2) anos. Para o valor de p<0,05, houve diferenças entre os momentos para o conhecimento dos cuidados da monitorização (valores da glicemia de jejum e pós-prandial, descarte dos insumos, sinais/sintomas, prevenção e tratamento da hipoglicemia e da hiperglicemia) e da frequência diária da monitorização da glicemia capilar. O programa educativo contribuiu com a melhora do conhecimento e com a frequência da monitorização da glicemia capilar / This was an evaluative study, developed by means of an analysis of results prior to and after an intervention, whose main objective was to evaluate the contribution of an educational program to capillary glucose monitoring in people with type 2 diabetes mellitus. The sample was made of 82 people, in ambulatory follow-up at a hospital that provides tertiary health care in the interior of the state of São Paulo. The educational interventions were developed in an open group, using the tool \"Diabetes Conversation Maps\", grounded on principles of the Cognitive Social Theory. The educational program was developed in four sessions, with an average duration of one hour and fifteen minutes for each subject, namely: physiopathology; disease control and complications; feeding and physical education; medications, capillary glucose monitoring, and insulin. In addition to these sessions, there were also two meetings for data collection; the first was held prior to intervention, and the second after their completion. At the third meeting, the researchers emphasized the care required for monitoring capillary glucose, and handed the participants with glucometers and materials for assessing capillary glucose at home. Descriptive statistics were used for sample characterization. The McNemar test was used for data analysis, and the Wilcoxon test and Spearman\'s correlation for categorical variables, with significance set at 5% (alpha = 0.05). Sample characteristics that stood out include: 48 (58.54%) participants were women, and respective mean values were 60.4 (SD=8.4) years of age; 4.86 (SD=3.86) years of education, and 15.3 (SD=8.2) years since the disease diagnosis. For the value of p<0.05, there were differences among the moments for learning about the monitoring care (interpretation of results, postprandial glucose levels, glucometer calibration, disposal of the materials, cleansing of the puncture site, knowledge of the terms hypoglycemia and hyperglycemia, conducts towards hypoglycemia and prevention of hypoglycemia and hyperglycemia) and the daily frequency of the capillary glucose monitoring. The educational program contributed to improve the knowledge and frequency of capillary glucose monitoring

Type 2 diabetes mellitus affects patients' health across the globe and is costly to manage. The chronic high blood sugar of diabetes is linked to cardiovascular and kidney damage, impaired functional status, and multiple organ failure. To lessen the complications associated with diabetes and promote self-care in those with the disease, health care professionals must be vigilant in offering diabetes education to patients with each clinic or primary care visit. Lack of diabetic educators in the clinic that provided the setting for this study indicated a need to increase clinical staff competency in teaching self-care and diabetes management to patients. The resulting project, guided by Bandura's theory of social learning, involved the creation of an educational curriculum, which was evaluated by 5 content experts with 5 or more years of experience caring for adult patients with Type 2 diabetes mellitus who provided narrative feedback. The content experts indicated satisfaction with the program and offered the following recommendations: (a) implementation of staff coaching on motivational interviewing, (b) additional help in securing medications and blood glucose testing supplies for noninsured patients, (c) translation of patient tools into Spanish at a Grade 3 or 4 reading level for better patient understanding, and (d) proceeding with full implementation after the recommendations are carried out. Improved self-care among diabetes patients could promote positive social change through the prevention of acute, long-term complications and disability.

As the number of people with diabetes continues to increase, research efforts improving glucose testing methods and devices are under way to improve outcomes and quality of life for diabetic patients. This dissertation describes the design and testing of a Data Acquisition Unit (DAU) providing low noise photocurrent spectra for use in a continuous glucose monitoring system. The goal of this research is to improve the signal to noise ratio (SNR) of photocurrent measurements to increase glucose concentration measurement accuracy. The glucose monitoring system consists of a portable monitoring device and base station. The monitoring device measures near infrared (IR) absorption spectra from interstitial fluid obtained by microdialysis or ultrafiltration probe and transmits the spectra to a base station via USB or a ZigBee radio link. The base station utilizes chemometric calibration methods to calculate glucose concentration from the photocurrent spectra. Future efforts envisage credit card-sized monitoring devices. The glucose monitor system measures the optical absorbance spectrum of an interstitial fluid (ISF) sample pumped through a fluid chamber inside a glucose sensor. Infrared LEDs in the glucose sensor illuminate the ISF sample with IR light covering the 2.2 to 2.4 micron wavelength region where glucose has unique features in its absorption spectrum. Light that passes through the sample propagates through a linearly variable bandpass filter and impinges on a photodiode array. The center frequency of the variable filter is graded along its length such that the filter and photodiode array form a spectrometer. The data acquisition unit (DAU) conditions and samples photocurrent from each photodiode channel and sends the resulting photocurrent spectra to the Main Controller Unit (MCU). The MCU filters photocurrent samples providing low noise photocurrent spectra to a base station via USB or Zigbee radio link. The glucose monitoring system limit of detection (LOD) from a single glucose sensor wavelength is 5.8 mM with a system bandwidth of 0.00108 Hz. Further analysis utilizing multivariate calibration methods such as the net analyte signal method promise to reduce the glucose monitoring system LOD approaching a clinically useful level of approximately 2 mM.