Search Results

1 - 10 of 79 items :

  • Biomedical Electronics x
Clear All
Correlation of rheoencephalography and laser Doppler flow: a rat study

Introduction Applications of rheoencephalography for monitoring cerebral blood flow autoregulation The goal of neuromonitoring in both the neurosurgery intensive care unit, during transport of wounded military service members is to prevent brain damage that may occur due to failure of CBF AR. Currently, there is no single measuring modality capable of monitoring for such brain injuries as hypoxia, ischemia, elevated ICP, edema, intracranial hemorrhage, vasospasm. CBF AR reflects the ability of the brain to keep brain blood flow relatively constant despite

Open access
Constructal Analysis of Thermal Flows in Electrical Machines

., Alexe, V., Sălişteanu, B., Nedelschi, A., Chirescu, R., Divoiu, C. Systemic analysis of the strategy of renewable energy sources, Scientific Bulletin of the Electrical Engineering Faculty - Year 15, No.4 (32), 2015 ISSN 1843-6188. [6] Bejan, A. Lorente, and S. The constructal Laws Thermodynamics of systems with flow configuration. Jour International Heat and Mass Transfer, vol. 47, 2004, p. 3073-3083. [7] Cohn, D. L. Optimal systems: The vascular system. Bull. Math. Biophys, vol. 16, 1954, p.59-74. [8] Shah, R. K., Sekulic, D. P. Fundamentals of heat

Open access
Measurement of cerebral blood flow autoregulation with rheoencephalography: a comparative pig study

). Relationship between Hemorrhage and Cerebral Blood Flow Hemorrhagic shock (hypotension) is the leading cause of death in both civilian and military injuries. A patient with both a severe head injury and hypotension is four times more likely to die than a patient with a head injury alone ( Manley et al, 2001 ). Despite the brain’s well developed autoregulation ( Strandgaard, Paulson, 1984 ), its vital functions are impaired when the CBF autoregulatory reserve is exhausted by prolonged hypovolemic conditions (hemorrhage). Afferent neural input to the brain seems to be

Open access
A system to monitor segmental intracellular, interstitial, and intravascular volume and circulatory changes during acute hemodialysis

in the body and may be a valuable aid in clinical diagnosis and research. Two different types of bioelectric impedance instruments are available. Fixed frequency bioelectrical impedance plethysmographic (IPG) techniques are valuable noninvasive tools that provide information about overall segmental volumes, blood flows, and hemodynamic status with a high degree of temporal resolution [ 9 , 10 , 11 , 12 ]. The second type, electrical bioimpedance spectroscopy (BIS) [ 13 , 14 ] is a multifrequency technique that, when coupled with computeraided equivalent

Open access
Detecting the Fault Section in the Distribution Network with Distributed Generators Based on Optimal Placement of Smart Meters

.E., El-Saadany, E.F., El Shatshat, R. and Zidan, A., 2011. A generalized power flow analysis for distribution systems with high penetration of distributed generation. Electric Power Systems Research, 81(7), pp.1499-1506. [16] Teng, J.H., 2008. Modelling distributed generations in three-phase distribution load flow. IET generation, transmission & distribution, 2(3), pp.330-340. [17] Baran, M.E. and Wu, F.F., 1989. Network reconfiguration in distribution systems for loss reduction and load balancing. IEEE Transactions on Power delivery, 4(2), pp.1401

Open access
Segmental intracellular, interstitial, and intravascular volume changes during simulated hemorrhage and resuscitation: A case study

of vital signs such as heart rate, blood pressure, temperature, and respirations comprise the hemodynamic quantities classically evaluated in hemorrhagic shock, these quantities mostly reflect the integrated effects of fundamental changes in blood flows and blood volumes that are progressively perturbed during the stages of blood loss. Thus in their classic review of the hemodynamic and neuroendocrine consequences of hemorrhagic hypovolemia, Schadt and Ludbrook [ 1 ] refer to the earlier human venesection studies of Barcroft [ 2 ] in which rapid and highly

Open access
Comparison of cerebrovascular reactivity tests: a pilot human study

of rheoencephalography for noninvasive continuous brain monitoring, including enhanced computational methods, animal studies and clinical monitoring studies of humans. Positive characteristics of REG are that it is noninvasive and is easy and inexpensive to administer continuously. However, before the availability of computerized data processing techniques, the usefulness of REG for neuromonitoring was limited since REG does not reflect absolute blood flow or provide direct diagnostic information; in addition, the REG signal may be contaminated by artifacts due

Open access
The effect of heart pulsatile on the measurement of artery bioimpedance

current and the generated electric field. The laminar flow module is selected to simulate and calculate the characteristics of blood motion based on its fluid dynamic properties. The frequency domain study is favored in order to compute the generated electric field at a specific range of frequencies. The laminar flow is used to simulate the motion of blood. The time-dependent study is preferred to compute the change in the motion of blood over time. The processing stage As shown in Fig.1 , the processing stage contains: firstly, the geometry: which contains the

Open access
Simulation of impedance measurements at human forearm within 1 kHz to 2 MHz

bioimpedance considering a forearm section. This can provide an insight to the arm tissue behavior along with the individual contribution of different layers (along with blood flow) to the impedance variations. Also, the forearm provides a simpler and justifiable site for PWV measurement The objective of this work is to simulate the electrical response of a section of human forearm and obtain the values of impedance over a wide frequency range. These simulation results will be compared to the Cole type response. The simu-lation would be performed at three instances of

Open access
Studies in Rheoencephalography (REG)

influenced by such factors as geometry, tissue conductivity, and blood flow. This complexity makes it difficult to measure reliably an isolated physiologic parameter, which has been the principal factor limiting use of impedance measurement applications. The applications widely used in clinical medicine are apnea monitoring, thoracic impedance/cardiac output measurement and the detection of venous thrombosis. Other potential applications, such as those described here, need further studies [ 3 , 5 , 6 ]. The disadvantage of REG as well as laser Doppler flowmetry for use

Open access