Introduction: The right use of BLOOD is necessary because of the high cost of correct BLOOD screening, BLOOD grouping, and cross match. The purpose of this study is to evaluate the rate of the reserved and cross matched BLOOD before elective surgeries which were done in Bahman 22nd Hospital. It also aims at evaluating the standard guideline for ordering BLOOD.Materials and Methods: This is a retrospective study from 1380 to 1388 that evaluates evaluating 6145 files of the patients hospitalized in 22 Bahman 22nd Hospital for surgery during the years of 1380 to 1388. The elective operations include General surgery, Gynecology, orthopedic, ENT, Urology and Neurosurgery. The number of patients, the number of reserved and cross matched units and the number of transfused units was recorded for each group of patients collected in each groups. Finally, the number of reserved BLOOD units in that period of time and in each group was compared with the standard guideline. Also the number of transfused BLOOD units was evaluated. The ratio of cross matched to transfused BLOOD units lower than 2.5 was considered as standard. And The obtained data were analyzed, using with SPSS.Results: A total of 1557 BLOOD units of BLOOD were reserved for 772 patients.1305 units (66.47%) were cross matched, but just 126 units (8.1%) were transfused. The effective factors in increasing the possibility of transfusion were the ages<20 & >80 years old, Hb £ 12, the type of surgery and the surgeon. Although after the application of the guidelines in1385, there was 64.44% decrease in the rate of cross matching rate due to the decrease in the number of patients who were cross matched, but the average of cross matched units for each patient did not change. The total of C/T index of the hospital decreased from 14.1 to 3.7.Conclusion: The appropriate correct BLOOD reserving can decrease the unnecessary BLOOD reserves, lower the pressure on BLOOD banking centers and prevent BLOOD wastage.

In this paper pulsatile laminar BLOOD flow in an axisymmetric stenosed tube is simulated by the Non-Newtonian Power law model. Effect of stenosis, for severe condition of 75% reduction of local area was considered and the flow patterns for three Womersley numbers were studied. The results show that there is a fundamental difference in the flow pattern at Wo=12.5. This difference is related to second co-rotating vortex which is observed downstream of stenosis at Wo=12.5. The propagation of disturbance that leads to formation of this vortex is shown by wall shear stress surface at Wo=12.5. Examining three flow patterns shows that the time that primary vortex forms on the distal face of stenosis is delayed with increasing Womersley number.

Retinal image analysis has many applications in various fields such as biometrics or medical diagnosis. BLOOD vessel segmentation is the first and important stage in these analyses. This paper presents an efficient method for automatic segmentation of BLOOD VESSELS in retinal images. In the first stage, the proposed algorithm uses a template matching technique for reducing the effect of optical disk in the image. Then, it uses a new local processing operation based on the statistical properties of the image in order to enhance the vessel/background contrast. Next morphological operations are used for filling the vessel spaces caused by the previous stages. Finally, a binary image containing BLOOD VESSELS is resulted by histogram thresholding of the contrast enhanced image.Evaluation of the results obtained by the new segmentation algorithm demonstrated its superior sensitivity and comparable accuracy with respect to the results of the previous works.

Bifurcated VESSELS represent a typical vascular unit of the cardiovascular system. In this study, the BLOOD flow in symmetric and asymmetric bifurcated VESSELS are simulated based on computational fluid dynamics method. The BLOOD is modeled as non-Newtonian fluid, and the pulsatile flow velocity is applied on the inlet. The effects of the fluid model, bifurcation angle and symmetry of the geometry of the vessel are investigated. The results show that the wall shear stress (WSS) on the outer wall of daughter branches for the non-Newtonian fluid flow is greater than that for Newtonian fluid flow, and the discrepancy between the flow of two fluid models is obvious at relatively low flow rates. With the bifurcation angle increases, the peak axial velocity of the cross-section of daughter branch decreases, so the WSS increases. For the non-Newtonian fluid flow in the asymmetric bifurcated VESSELS, more flow passes through the daughter vessel with a lower angle, and the WSS along the outer wall of which is lower. Furthermore, the region with a low time-averaged wall stress (TAWSS) and high oscillating shear index(OSI) distributed on the outer wall of bifurcation VESSELS are larger for the flow in the vessel with smaller bifurcation angle. In conclusion, the effects of the BLOOD viscosity cannot be neglected at low flow rates and the geometry of the bifurcated vessel plays a key role with regards to the BLOOD flow.