Mana Sezdi

Storage effects on the Cole-Cole parameters of erythrocyte suspensions

Chemical alterations of red blood cells (RBCs) during storage eventually affect the electrical properties of blood. In this study, the physiological parameters such as extracellular (SAGM + CPD + residual plasma) Na(+), K(+), Cl(-), pH, 2,3-DPG and ATP together with the Cole-Cole parameters were measured using erythrocyte suspensions from 51 male donors (31 donors form the training set and 20 donors are used for testing), on the 0th, 10th, 21st, 35th and 42nd days of storage. During storage, while the surrounding fluid resistance (R(e)) and the effective cell membrane capacitance (C(m)) increased progressively with time, the intracellular fluid resistance (R(i)) has decreased. Storage of RBCs resulted in a rise in K(+) and a fall in Na(+), Cl(-), pH, 2,3-DPG and ATP. Accordingly, electrical parameters were all correlated with Na(+), K(+), Cl(-), pH and ATP at varying levels. By applying multi-regression analysis, it is concluded that R(i), R(e) and C(m) are appropriate for modeling Na(+), K(+), Cl(-), pH and ATP during storage.

Electrical parameters of human blood

Blood samples taken from healthy donors are diluted with 0.9% saline, to obtain samples with hematocrit values ranging from 31 to 50. Bio-impedance spectroscopy is then performed on these samples. Complex impedance measurements in the frequency range from 100 kHz to 1 MHz were fitted into Cole-Cole diagrams, using a LMS algorithm. Data were interpreted in terms of an equivalent resistor-capacitor circuit. In this hematocrit range, all four Cole-Cole parameters R/sub c/, R/sub i/, F/sub c/, and /spl alpha/, are shown to be a linear function of hematocrit. With increasing concentration of red blood cells, the intracellular conductivity is also increased while extracellular conductivity is reduced and, Cole-Cole plots are shifted upwards to the right, in the complex plane, indicating a higher /spl alpha/ and a lower F/sub c/. We suggest that, parameters R/sub c/, R/sub i/, F/sub c/, and /spl alpha/, are a potential index for clinically evaluating blood samples.

Hematocrit dependence of the Cole-Cole parameters of human blood

The specific impedance of human erythrocytes suspended in plasma was measured in the frequency range from 100 kHz to 1 MHz, in samples from nine healthy donors. These samples were diluted with 0.9% saline in different volumes to obtain samples with different hematocrit values, ranging from 31 to 50. The complex impedance was measured as a function of frequency and then fitted into Cole-Cole diagrams, with rms errors of less than 0.5%, using a LMS algorithm. Data were interpreted in terms of an equivalent resistor-capacitor circuit. In this hematocrit range, Cole-Cole parameters R/sub e/, R/sub i/, F/sub c/, and a in turn are shown to be a linear function of hematocrit (0.98<r<1). As the concentration of red blood cells in blood samples is augmented, the intracellular conductivity is increased while extracellular conductivity is reduced, and Cole-Cole plots are shifted upwards to the right, in the complex plane, indicating a higher /spl alpha/ and a lower f/sub c/. Cole-Cole parameters might be a potential index for evaluating blood in clinical applications.

Physiological quality assessment of stored whole blood by means of electrical measurements

The physiological parameters of blood such as extracellular Na+, K+, Cl−, pH, 2,3-DPG and ATP and the complex electrical impedance were measured using whole blood samples from 31 male donors (21 donors form the training set and ten donors were used for testing), on the 0th, 10th and 21st day of blood bank storage. During storage, while the extracellular fluid resistance (Re) and the intracellular fluid resistance (Ri) decreased progressively with time, the effective cell membrane capacitance (Cm) has increased. Blood bank storage resulted in a rise in K+ and a fall in Na+, Cl−, pH, 2,3-DPG and ATP. Accordingly, all electrical parameters correlated with Na+, K+, Cl−, pH and ATP, at varying levels. By applying the multi-regression analysis, it was demonstrated that Ri, Re and especially Cm were appropriate for the assessment of Na+, K+, Cl−, pH and ATP until the 21st day of storage.

Changes in Electrical and Physiological Properties of Human Blood During Storage

In this study, the relationship between physiological parameters and electrical impedance changes of human blood and their further clinical implications are investigated. The study is performed on 255 erythrocyte suspension samples derived from 51 male donors. The samples are stored at 4degC and measurements are done on the (0^th, 10^th, 21^st, 35^th and 42^nd days of storage. The complex impedance is measured in the frequency range from 100 kHz to 1 MHz. The extracellular resistance R_e and the effective cell membrane capacitance C_m increased progressively with storage time while the intracellular resistance ri has decreased. Electrical impedance alterations are explained in terms of the measurements of Na⁺, K⁺ and Cl^- concentrations, pH and ATP. Storage of red blood cells resulted in a rise in the extracellular K⁺ and a fall in the extracellular Na⁺, Cl^-, pH and ATP. Variance analysis (ANOVA) is used to evaluate any variations in blood parameters, in relation to storage time. According to the (SPSS) regression analysis, R_i and R_e are highly correlated with Na⁺, K⁺, Cl^- and pH and, more significantly with ATP. The Cole-Cole parameters F_c and alpha showed very little change with storage time and C_m had weak correlations with blood parameters. Results show that complex impedance measurements may serve as a useful indicator in the quality assessment of blood bank stored blood samples

Estimating the resistivity of the interior fluid of red blood cells using Fricke's equation

Multifrequency (1 kHz-1 MHz) impedance of human blood, from 8 donors, for the hematocrit range from 36% to 43.5%, is measured using the true four-probe technique, Cole-Cole parameters, that are characteristic of blood, are used to model the equivalent electrical circuit. Results are then applied to Frickes theory of suspension of particles at f/spl rarr/0 and f/spl rarr//spl infin/. Frickes equation, so far, has been widely used at f/spl rarr/0 In determining the shape factor for red cells or the hematocrit of blood samples. Here, it is shown that, solution of Frickes equation of suspension at f/spl rarr//spl infin/ can be used in calculating the inside resistivity /spl rho//sub c/ of red cells. The authors suggest that /spl rho//sub c/ should replace the Cole-Cole parameter /spl rho//sub i/. This parameter, together with Cole-Cole parameters might be a potential index for evaluating blood in clinical applications.

Anesthetic gas concentration changes related to the temperature and humidity in high and low flow anesthesia.

The objective of this study, is to investigate the effects of the temperature and the humidity to the amount of anesthetic gas output from the vaporizer in both high and low flow anesthesia, and to attract attention to this relationship during the delivery of anesthesia and the calibration measurements. The performance of the anesthesia vaporizer (isoflurane and sevoflurane) was evaluated in both high and low flow anesthesia, and it was investigated whether the vaporizer supplied the preset amount of anesthetic to the patient. Then, through changing the temperature of the anesthetic device between 20 and 36 degrees C, and through changing the humidity between 20% and 42%, the changes in the gas concentration were measured. After measurements, the results were studied statically. For high and low flow anesthesia, the regression equations were obtained and it was seen that these equations were acceptable.

Performance control of medical devices in the Cerrahpaşa Faculty of Medicine in Istanbul University

In this study, a project was developed for performance control of the medical devices in the Cerrahpasa Health Faculty in Istanbul University. The calibration measurements of these medical devices were performed and the measurement results were interpreted in according to the IPM “Inspection and Preventive Maintenance System” procedures which are developed by ECRI (Emergency Care Research Institute). By using these results, the statistical graphics and values were obtained. In the developed project, CSS(Cascading Style Sheets), PHP(Personal Home Page), MySQL(Structured Query Language) and JavaScript languages which are implemented to the XHTML(Extensible HyperText Markup Language), were used. With this study, it was thought that the following of the medical devices in the Health Faculty could be easier. The usibility of this studys result showed how much we were right. For the future, we have the preparations to expand this study to the other departments and Çapa Health Faculty in I.U.

Radiation leakage tests in the Radiology Department of Istanbul Faculty of Medicine in Istanbul University

During the X-Ray machines are used, if the protection from X-Ray is insufficient, not only the patient but also the user is exposured with high X-Ray dosage and he/she is affected from X-Ray in related to the dose level. In this study, by testing the radiological leakage in Radiology Departmant of Istanbul Health Faculty in Istanbul University, the effects of X-Ray to both the user and the patients who are located near the radiography room, were investigated. For 100 kVp and 50 mAs, the measurements were performed in front of the user barrier (5 cm) and in the back of the user barrier (5 cm) to observe the amount of the radiation dose of the user, and they were performed when the door is open and closed to observe it of the patients who are located in the hall. From the measurement results, it was seen that the user barriers are appropriate to the standards in except for 1 room. In result, the knowledge about the radiation dose affecting the user was obtained, and by informing the user and the management of the hospital, the necessary regulations were planned.

The effects of temperature changes to the anesthetic gas concentration

Within the framework of quality management in medical services, the calibration gains great importance through appropriacy of medical devices. The aim of this study is to investigate the effects of temperature factor to the amount of gas output from the vaporizatör and to enhance the consideration of these factors while adjusting the amount of gas to be given to the patient during the operation. In this study, the performance of the anesthesia vaporizer (isoflurane and sevoflurane) was evaluated and it was investigated whether it the vaporizer supplied the dialed amount of anesthetic to the patient. Then, through changing the temperature of anesthetic device between 20İ36°C, the changes in the concentration of isoflurane and sevoflurane gases were measured. In conclusion, it was observed that there is no considerable change on the gas concentration in the 20İ36°C temperature range.