A new smartphone-based method for wound area measurement.

Proper wound healing can be assessed by monitoring the wound surface area. Its reduction by 10 or 50% should be achieved after 1 or 4 weeks, respectively, from the start of the applied therapy. There are various methods of wound area measurement, which differ in terms of the cost of the devices and their accuracy. This article presents an originally developed method for wound area measurement. It is based on the automatic recognition of the wound contour with a software application running on a smartphone. The wound boundaries have to be traced manually on transparent foil placed over the wound. After taking a picture of the wound outline over a grid of 1 × 1 cm, the AreaMe software calculates the wound area, sends the data to a clinical database using an Internet connection, and creates a graph of the wound area change over time. The accuracy and precision of the new method was assessed and compared with the accuracy and precision of commercial devices: Visitrak and SilhouetteMobile. The comparison was performed using 108 wound shapes that were measured five times with each device, using an optical scanner as a reference device. The accuracy of the new method was evaluated by calculating relative errors and comparing them with relative errors for the Visitrak and the SilhouetteMobile devices. The precision of the new method was determined by calculating the coefficients of variation and comparing them with the coefficients of variation for the Visitrak and the SilhouetteMobile devices. A statistical analysis revealed that the new method was more accurate and more precise than the Visitrak device but less accurate and less precise than the SilhouetteMobile device. Thus, the AreaMe application is a superior alternative to the Visitrak device because it provides not only a more accurate measurement of the wound area but also stores the data for future use by the physician.

Microdialysis monitoring of glucose, lactate, glycerol, and pyruvate in patients with diabetic ketoacidosis.

PURPOSE: The objective was to assess glucose, lactate, glycerol, and pyruvate concentrations in the interstitial fluid of the adipose tissue as well as the glucose relative recovery coefficient in reference to capillary blood (RC) during the first two days of the standard treatment of diabetic ketoacidosis (DKA) in patients with type 1 and type 2 diabetes. MATERIALS AND METHODS: The study group consisted of 19 patients (12 with type 1 diabetes and 7 with type 2 diabetes). The metabolic state of the patients was monitored using the microdialysis technique. The analysis of variance was used to investigate whether the type of diabetes and the duration of treatment influenced the assessed parameters. RESULTS: Concentrations of all the monitored components were stable after the initial 12 h of treatment. Glucose concentration was higher and concentrations of all the other components were lower (p<0.0001) in patients with type 1 diabetes than in patients with type 2 diabetes. Significantly higher RC was observed in patients with type 1 diabetes during the initial 12 h. CONCLUSIONS: The results suggest that the standard treatment of DKA is effective in stabilizing a concentration of the studied metabolic components in the interstitial fluid in patients with type 1 and type 2 diabetes despite differences in the glucose concentration at the beginning of the treatment.

Accuracy and precision of selected wound area measurement methods in diabetic foot ulceration.

AIM: The present study assesses precision and accuracy of four selected methods of wound area measurements in diabetic foot wounds. MATERIALS AND METHODS: The areas of 16 wound shapes were measured using linear measurement with elliptical estimation (Elliptical method), using the Visitrak™ (Smith & Nephew, London, United Kingdom) device, the SilhouetteMobile™ device (ARANZ Medical Ltd., Christchurch, New Zealand), and the TeleDiaFoS system (Nalecz Institute of Biocybernetics and Biomedical Engineering, Warsaw, Poland). The actual area of a wound shape was determined with a tested scanner and specifically developed software. Accuracy of the area measurement method was assessed by the relative error (RE), whereas precision was assessed by the coefficient of variation (CV). RESULTS: The overall absolute REs were 13.3%, 6.8%, 2.1%, and 2.3% for the Elliptical method, the Visitrak device, the TeleDiaFoS system, and the SilhouetteMobile device, respectively. The accuracy of the Visitrak device was remarkably reduced for wound areas smaller than 2 cm². The overall CVs were 6.0%, 6.3%, 1.6%, and 3.1% for the Elliptical method, the Visitrak device, the TeleDiaFoS system, and the SilhouetteMobile device, respectively. The precision of the Visitrak device was revealed to be remarkably lower for small wounds (<2 cm²). CONCLUSIONS: The Elliptical method gives overestimation up to 33%; thus, it should not be used in applications where the actual wound area is an important parameter (like the prediction of wound healing). The TeleDiaFoS system and the SilhouetteMobile device showed the best accuracy of all used methods; however, the precision of the TeleDiaFoS system was revealed to be higher than the precision of the SilhouetteMobile device. The accuracy and the precision of the Visitrak device are significantly reduced for wounds smaller than 2 cm².

What we can really expect from telemedicine in intensive diabetes treatment: 10 years later.

During the last 10 years many new telematic systems aiming at support of diabetes treatment have been designed and developed. Most systems that were applied in clinical randomized trials used the classical approach, with data transfers from patients performed usually once every few days. In the few available meta-analyses of these trials, a significant improvement of the mean hemoglobin A1c was demonstrated in patients using telematic systems. However, the magnitude of this improvement in comparison with the control groups was lower than expected. This conclusion was confirmed by results of the IDEATel study involving more than 1,600 patients over a period of 5 years. It might by hypothesized that in some groups of patients continuous telecare with frequent contacts between patients and the care provider during each day should be required. This hypothesis is confirmed by the results of the clinical trials applying real-time diabetes monitoring systems. However, the increased frequency of the data transfers and checkups requires a new model for technology-supported care. The new model should connect together the ubiquitous data transfer with an automatically selected optimal frequency, the automatic assessment of the data coupled with quicker feedback from the decision support system or from the provider, and selection of the optimal time for the patient's face-to-face visit in the clinic. All this new future implementations together with already confirmed advantages of the telematic support, such as the increase of self-confidence of the patient, will hopefully give real benefits for the patients.

Hemoglobin glycation rate constant in non-diabetic Individuals.

The objectives were as follows: (1) estimating mean value of the overall hemoglobin glycation rate constant (k); (2) analyzing inter-individual variability of k; (3) verifying ability of the hemoglobin A1c (HbA1c) formation model to predict changes of HbA1c during red blood cells cultivation in vitro and to reproduce the clinical data. The mean k estimated in a group of 10 non-diabetic subjects was equal to 1.257 ± 0.114 × 10(-9) L mmol(-1) s(-1). The mean k was not affected by a way of estimation of glycemia. The mean k differed less than 20% from values reported earlier and it was almost identical to the mean values calculated on basis of the selected published data. Analysis of variability of k suggests that inter-individual heterogeneity of HbA1c formation is limited or rare. The HbA1c mathematical model was able to predict changes of HbA1c in vitro resulting from different glucose levels and to reproduce a linear relationship of HbA1c and average glucose obtained in the A1C-Derived Average Glucose Study. This study demonstrates that the glycation model with the same k value might be used in majority of individuals as a tool supporting interpretation of HbA1c in different clinical situations.

Area of the diabetic ulcers estimated applying a foot scanner-based home telecare system and three reference methods.

BACKGROUND: Diabetic foot ulcer area is a basic parameter used for monitoring the wound healing and effectiveness of the treatment applied. TeleDiaFoS (developed earlier in collaboration with the Department and Clinic of Gastroenterology and Metabolic Diseases, Medical University of Warsaw, Warsaw, Poland) is one of just a few systems available that make possible monitoring of the wound size remotely based on the foot scans transmitted to the physician from a patient's home. The aim of this study was to compare the diabetic foot ulcer areas measured using TeleDiaFoS with the results obtained using three reference methods. METHODS: The reference measurements were conducted using the elliptical method with a ruler, the wound tracing method and planimetrics with the Visitrak (Smith & Nephew, London, UK) system, and the pattern-coded structured light method with the Silhouette (ARANZ Medical, Christchurch, New Zealand) system. Regression and Bland-Altman analyses were performed. The study group consisted of 23 diabetes patients with plantar foot ulcers. RESULTS: Thirty-three wounds were successfully examined. The measurement method influenced the measured area significantly (P=0.00005). The correlation coefficients between TeleDiaFoS and the ruler, Visitrak, and Silhouette methods were 0.949, 0.985, and 0.987, and the limits of agreement equaled -1.3±5.5 cm(2), -0.4±2.2 cm(2), and -0.6±2.1 cm(2), respectively. The strong linear relationships obtained can be used to convert the wound area measured with TeleDiaFoS to the corresponding value of each of the reference methods. CONCLUSIONS: The results indicate that the wound area of plantar ulcers in diabetes might be monitored effectively using the TeleDiaFoS system based on the foot scans that the patient can produce at home with no assistance of other persons.

A new imaging and data transmitting device for telemonitoring of diabetic foot syndrome patients.

BACKGROUND: Proper healing of ulcers and wounds on the feet of diabetes patients is important in order to prevent amputation. If the wound area reduction during the first 4 weeks of the treatment is not 40% or more, reevaluation of the treatment is necessary. The wound area evaluation is not complicated when the patient stays at a hospital, but when he or she goes home the physician does not have a tool allowing monitoring of the wound area. METHODS AND RESULTS: The aim of the present article is to present a new device able to take a wound picture and send it automatically to the database. This device, called the Patient's Module (PM), is also able to download data from the memories of blood pressure and blood glucose meters and send the data to the database. The PM is able to operate within the TeleDiaFoS system (developed earlier in collaboration with the Department and Clinic of Gastroenterology and Metabolic Diseases, Medical University of Warsaw, Warsaw, Poland) aimed at monitoring of treatment of patients with diabetic foot syndrome. The PM was tested on 10 type 2 diabetes patients during a 3-month period. CONCLUSIONS: The study revealed that the PM can be used as a home telemonitoring device, and the analysis of the data sent from patient's home enables the assessment of wound healing progress, giving the physician the possibility for earlier change of the treatment if the wound area reduction is not satisfactory.

Monitoring of diabetic foot syndrome treatment: some new perspectives.

Diabetic foot syndrome (DFS) is one of the major complications of diabetes, and it can lead to foot amputations. It is very important to assure good medical care for diabetic patients not only during their stay at hospital but also at home. Telecare can be one good solution for extending medical care to patients' homes. There are some reports regarding the application of new technologies in this field. The standard current model of telecare of DFS includes experts at hospital who conduct clinical examinations and decision making at a distance, in close cooperation with a visiting nurse and the patient. In the present paper a new paradigm of the DFS's telecare is introduced, which eliminates the visiting nurse. The designed and developed TeleDiaFoS system consists of a traditional database and mobile patient's module (PM) allowing for documentation of the foot images as well as the results of blood glucose and blood pressure measurements taken by the patient himself at home. A 2-year validation of the TeleDiaFoS system on 10 DFS patients (3 months each) proved its usefulness and led to acceptance of this type of technical support by patients and physicians. The designed and developed system and proposed sterilization procedure of the PM have been found to be easy to use by the patient at home.

Validation of hemoglobin glycation models using glycemia monitoring in vivo and culturing of erythrocytes in vitro.

Glycated hemoglobin A1c (HbA1c) concentration in blood is an index of the glycemic control widely used in diabetology. The aim of the work was to validate two mathematical models of HbA1c formation (assuming irreversible or reversible glycation, respectively) and select a model, which was able to predict changes of HbA1c concentration in response to varying glycemia courses with higher accuracy. The experimental procedure applied consisted of an original combination of: in vivo continuous glucose concentration monitoring, long-term in vitro culturing of the human erythrocytes and mathematical modeling of HbA1c formation in vivo and in vitro with HbA1c values scaled according to the most specific analytical methods. Sixteen experiments were conducted in vitro using blood samples collected from healthy volunteer and stable type 1 diabetic patients whose glycemia was estimated beforehand based on long-term monitoring. The mean absolute difference of the measured and predicted HbA1c concentrations for the in vitro experiments were equal to 0.64 +/- 0.29% and 1.42 +/- 0.16% (p = 0.0007) for irreversible and for reversible model, respectively, meaning that the irreversible model was able to predict the glycation kinetics with a higher accuracy. This model was also more sensitive to a deviation of the erythrocytes life span.

Microdialysis technique as a monitoring system for acute complications of diabetes.

The objective of the study was to establish the quasi-continuous courses, using microdialysis technique, of glucose, lactate, and glycerol concentrations in interstitial fluid of abdominal adipose tissue during the standard treatment of acute diabetes complications. Clinical studies were carried out on 31 diabetic patients during the initial 48 h of the treatment. In all but two obese female patients with hyperglycemic hyperosmolar state (HHS) did glucose concentration in perfusion fluid (PF) reflect concentration in capillary blood. The recovery of glucose correlated with patients' body mass index (r = 0.55). It was significantly higher in lean and overweight patients (91 +/- 15%) than in obese patients (55 +/- 31%). The course of lactate concentration in PF coincided with the course in venous blood (2.1 +/- 0.3 mmol/L vs. 2.0 +/- 0.5 mmol/L, P = 0.35). Glycerol concentration was 267 +/- 41 micromol/L and 133 +/- 40 micromol/L in PF and venous blood, respectively (P = 0.004). The study indicated that microdialysis may be an effective tool to monitor concentration of different metabolites in interstitial fluid of the adipose tissue during treatment of the acute complications of diabetes. Applicability of the technique in the monitoring of HHS, especially in obese female patients, needs further investigation.

Home telecare during intensive insulin treatment--metabolic control does not improve as much as expected.

We examined the influence of the increased frequency of data reporting on metabolic control in patients with diabetes. Data reporting was via a home telecare system that stored blood glucose values and was integrated with a simple electronic logbook. The data collected by the patient were automatically transmitted via the telephone network every night. The study population consisted of 30 patients with type I diabetes, who were randomly allocated to the home telecare group or the control group. The control group was treated based on clinical examinations performed every three weeks. In the home telecare group, the patient-collected data were transmitted to hospital daily, enabling more frequent interventions by the doctor. The average study period was 180 days (SD 22) in the home telecare group and 176 days (SD 16) in the control group. The mean level of metabolic control and the insulin dose adjustment patterns were very similar in both groups regardless of the much higher (15 times) reporting frequency in the home telecare group. The patient-collected data were not fully utilized, mainly because of too high within-day variability in glycaemic control and the high workload connected with daily data analysis.

Toward the improvement of diabetes treatment: recent developments in technical support.

Diabetes is recognized as one of the most severe health problem in the world. It spares no one, attacking men, women, children, and the elderly. Diabetes is the leading cause of kidney failure, blindness in adults, nervous system damage, and amputations. It is a major risk factor for heart disease, stroke, and birth defects. Diabetes is currently one of the most costly diseases in both human and economic terms. Diabetes is a metabolic disorder resulting from insulin deficiency, insulin resistance, or both. There are several possible realizations of the so-called artificial or bio-artificial pancreas (AP, BAP), systems which should automatically and efficiently substitute for the lost function of the # cells. Any types of AP/BAP are routinely used for the treatment of diabetes. Currently, for ambulatory insulin-treated diabetics, only application of intensive therapy can effectively delay the development and progression of the above-mentioned life-threatening late complications of diabetes. Ideal intensive insulin treatment should mimic as closely as possible the secretion of insulin by # cells in healthy people. The crucial factors that determine the efficiency of this type of treatment are the effective monitoring of the patient's glycemic control (monitoring phase) and the accurate delivery of insulin according to established algorithms (treatment phase). The monitoring phase includes blood glucose measurements, the transfer of all parameters measured and noted by the patient to a physician, and clear registration of the data. The treatment phase concerns selection of the optimal insulin regimen and effective insulin delivery to the patient. Delivery of insulin is most commonly realized either intermittently using multiinjection techniques or continuously by portable pumps. However, several others methods of delivery are under development. The main objective of this article is to discuss in detail recent technical developments in intensive insulin treatment, stressing the existing problems and reviewing the best applied solutions.

Impact of convective transport on dialyzer clearance.

The results of predictions of three mathematical models used to describe the impact of convective flow on dialyzer clearance are presented. These models are based on the ordinary differential equations, which describe changes of solute concentration and solute and fluid flows along the module length. One of the models takes into consideration the existence of the boundary layers on both sides of the membrane wall, by including in the equations two parameters kB and kD, which describe mass transport coefficients in blood and dialysate, respectively. In the second model, the boundary layers are included in one lumped membrane permeability parameter. The diffusive membrane permeability was calculated from pure diffusive clearance, which was taken from experimental results. In the third model, a linear dependence of transmittance coefficient and ultrafiltration flow was proposed. The theoretical results were compared with data obtained in experiments carried out in vitro with four types of high-flux hollow-fiber dialyzers. The comparisons demonstrate that the first two models are of similar accuracy and the third model is not suitable for small solutes.

Polypropylene hollow fiber for cells isolation: methods for evaluation of diffusive transport and quality of cells encapsulation.

Formulation of membrane properties is important prior the successful implantation of encapsulated cells producing therapeutically relevant compounds. The purpose of our study was to specify the methods allowing preliminary evaluation of hollow fibers (HF) chosen for immunoisolation. We have selected as estimates (1) diffusive permeability for small and large solutes, and HF cut off (in vitro), (2) histological evaluation of tissue overgrowth after sc. implantation into mice. It was found that diffusive coefficients were linearly dependent on the particle diameter except that of albumin (2-3 times higher than theoretically estimated). This discrepancy imply that for certain particles the interaction with membrane material may be significant. The histological evaluation showed that siliconized HF implanted for 105 days were accepted (there was thin fibrotic layer on the external surface of the HF, no surrounding haemopoietic cells were found). It is concluded that proposed methods for preliminary evaluation of hollow fibers chosen for immunoisolation seems to be reliable and suitable for testing diffusive permeability of each relevant cell product.