Thermal Analysis of Heat Transfer from Catheters and Implantable Devices to the Blood Flow

Implantable devices, ultrasound imaging catheters, and ablation catheters (such as renal denervation catheters) are biomedical instruments that generate heat in the body. The generated heat can be harmful if the body temperature exceeds the limit of almost 315 K. This paper presents a heat-transfer model and analysis, to evaluate the temperature rise in human blood due to the power loss of medical catheters and implantable devices. The dynamic of the heat transfer is modeled for the blood vessel, at different blood flow velocities. The physics and governing equations of the heat transfer from the implanted energy source to the blood and temperature rise are expressed by developing a Non-Newtonian Carreau–Yasuda fluid model. We used a Finite Element method to solve the governing equations of the established model, considering the boundary conditions and average blood flow velocities of 0–1.4 m/s for the flow of the blood passing over the implanted power source. The results revealed a maximum allowable heat flux of 7500 and 15,000 W/m2 for the blood flow velocities of 0 and 1.4 m/s, respectively. The rise of temperature around the implant or tip of the catheter is slower and disappeared gradually with the blood flow, which allows a higher level of heat flux to be generated. The results of this analysis are concluded in the equation/correlation T=310+H3000(1+e−7V), to estimate and predict the temperature changes as a function of heat flux, H, and the blood flow velocity, V, at the implant/catheter location.

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Patterns of Cerebral Blood Flow and Systemic Hemodynamics During Arithmetic Processing

Journal of Psychophysiology ◽

10.1027/0269-8803.22.2.81 ◽

2008 ◽

Vol 22 (2) ◽

pp. 81-90 ◽

Cited By ~ 21

Author(s):

Natalie Werner ◽

Neval Kapan ◽

Gustavo A. Reyes del Paso

Keyword(s):

Blood Pressure ◽

Blood Flow ◽

Cerebral Blood Flow ◽

Time Course ◽

Doppler Sonography ◽

Transcranial Doppler Sonography ◽

Systemic Hemodynamics ◽

Heart Period ◽

Blood Flow Velocities ◽

Flow Velocities

The present study explored modulations in cerebral blood flow and systemic hemodynamics during the execution of a mental calculation task in 41 healthy subjects. Time course and lateralization of blood flow velocities in the medial cerebral arteries of both hemispheres were assessed using functional transcranial Doppler sonography. Indices of systemic hemodynamics were obtained using continuous blood pressure recordings. Doppler sonography revealed a biphasic left dominant rise in cerebral blood flow velocities during task execution. Systemic blood pressure increased, whereas heart period, heart period variability, and baroreflex sensitivity declined. Blood pressure and heart period proved predictive of the magnitude of the cerebral blood flow response, particularly of its initial component. Various physiological mechanisms may be assumed to be involved in cardiovascular adjustment to cognitive demands. While specific contributions of the sympathetic and parasympathetic systems may account for the observed pattern of systemic hemodynamics, flow metabolism coupling, fast neurogenic vasodilation, and cerebral autoregulation may be involved in mediating cerebral blood flow modulations. Furthermore, during conditions of high cardiovascular reactivity, systemic hemodynamic changes exert a marked influence on cerebral blood perfusion.

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Effect of positioning from supine and left lateral positions to left lateral tilt on maternal blood flow velocities and waveforms in full-term parturients

Anaesthesia ◽

10.1111/j.1365-2044.2012.07268.x ◽

2012 ◽

Vol 67 (8) ◽

pp. 936-936 ◽

Cited By ~ 1

Author(s):

P. Kundra ◽

J. Velraj ◽

U. Amirthalingam ◽

S. Habeebullah ◽

K. Yuvaraj ◽

...

Keyword(s):

Blood Flow ◽

Maternal Blood ◽

Full Term ◽

Lateral Tilt ◽

Blood Flow Velocities ◽

Flow Velocities

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Blood Flow Velocities in the Vertebral Veins of Healthy Subjects: A Duplex Sonographic Study

Journal of Neuroimaging ◽

10.1111/jon199994198 ◽

1999 ◽

Vol 9 (4) ◽

pp. 198-200 ◽

Cited By ~ 10

Author(s):

Olaf Hoffmann ◽

Markus Weih ◽

Thomas von Münster ◽

Stephan Schreiber ◽

Karl Max Einhäupl ◽

...

Keyword(s):

Blood Flow ◽

Healthy Subjects ◽

Blood Flow Velocities ◽

Flow Velocities

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The Infrared Characteristics of the Wall Temperature of Boiling Heat Transfer in Microchannel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.383-390.811 ◽

2011 ◽

Vol 383-390 ◽

pp. 811-815

Author(s):

Hu Gen Ma ◽

Jian Mei Bai ◽

Rong Jian Xie ◽

Wen Jing Tu

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Wall Temperature ◽

Boiling Heat Transfer ◽

Transfer Test ◽

Axial Direction ◽

Transfer Model ◽

Micro Channel ◽

Vapor Quality ◽

Test Rig

In this paper, the boiling heat transfer test rig was designed and built, while the characteristics of boiling Heat Transfer of refrigerants in micro-channel was researched. The wall temperature of micro-channel was measured by TH5104 Infrared thermography. The results showed that there were obvious variations for wall temperature of micro-channel along the axial direction when boiling heat transfer occurred in the micro-channel. The temperature distribution affected obviously by the heat flux, mass flow rate; vapor quality and heat transfer model.

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A Heat Transfer Model of Dropwise Condensation Underneath a Horizontal Substrate

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.199-200.1604 ◽

2011 ◽

Vol 199-200 ◽

pp. 1604-1608

Author(s):

Yun Fu Chen

Keyword(s):

Heat Transfer ◽

Heat Flux ◽

Contact Angle ◽

Fractal Model ◽

Condensation Heat Transfer ◽

Droplet Growth ◽

Transfer Model ◽

Dropwise Condensation ◽

Small Contact Angle ◽

Horizontal Substrate

For finding influence of the condensing surface to dropwise condensation heat transfer, a fractal model for dropwise condensation heat transfer has been established based on the self-similarity characteristics of droplet growth at various magnifications on condensing surfaces with considering influence of contact angle to heat transfer. It has been shown based on the proposed fractal model that the area fraction of drops decreases with contact angle increase under the same sub-cooled temperature; Varying the contact angle changes the drop distribution; higher the contact angle, lower the departing droplet size and large number density of small droplets; dropwise condensation translates easily to the filmwise condensation at the small contact angle ;the heat flux increases with the sub-cooled temperature increases, and the greater of contact angle, the more heat flux increases slowly.

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Effect of physiological heart rate changes on left ventricular dimensions and mitral blood flow velocities in the normal fetus

Early Human Development ◽

10.1016/0378-3782(94)01595-g ◽

1995 ◽

Vol 40 (2) ◽

pp. 109-114

Author(s):

P.B. Tsyvian ◽

K.V. Malkin ◽

J.W. Wladimiroff

Keyword(s):

Heart Rate ◽

Blood Flow ◽

Left Ventricular ◽

Normal Fetus ◽

Left Ventricular Dimensions ◽

Blood Flow Velocities ◽

Ventricular Dimensions ◽

Flow Velocities

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Acute Effect of Hypervolemic Hemodilution on Retrobulbar Hemodynamics in Anterior Ischemic Optic Neuropathy

BioMed Research International ◽

10.1155/2018/4756313 ◽

2018 ◽

Vol 2018 ◽

pp. 1-6

Author(s):

Marion Bienert ◽

Niklas Plange ◽

Andreas Remky ◽

Kay Oliver Arend ◽

David Kuerten

Keyword(s):

Blood Flow ◽

Hydroxyethyl Starch ◽

Optic Neuropathy ◽

Acute Effect ◽

Anterior Ischemic Optic Neuropathy ◽

Ischemic Optic Neuropathy ◽

Hypervolemic Hemodilution ◽

Blood Flow Velocities ◽

Retrobulbar Hemodynamics ◽

Flow Velocities

Purpose.Ischemic ocular disorders may be treated by hypervolemic hemodilution. The presumed therapeutic benefit is based on a volume effect and improved rheological factors. The aim was to investigate the acute effect of intravenous hydroxyethyl starch on retrobulbar hemodynamics in patients with nonarteritic anterior ischemic optic neuropathy (NAION).Methods.24 patients with acute NAION were included. Retrobulbar hemodynamics were measured using color Doppler imaging before and 15 min after intravenous infusion of 250 cc 10% hydroxyethyl starch (HES). Peak systolic velocity (PSV), end diastolic velocity (EDV), and Pourcelot’s resistive index (RI) were measured in the ophthalmic artery (OA), central retinal artery (CRA), and short posterior ciliary arteries (PCAs).Results.After infusion of HES blood flow velocities significantly increased in the CRA (PSV from7.53±2.33to8.32±2.51 (p<0.001); EDV from2.16±0.56to2.34±0.55 (p<0.05)) and in the PCAs (PSV from7.18±1.62to7.56±1.55 (p<0.01); EDV from2.48±0.55to2.66±0.6 cm/sec (p<0.01)). The RI of all retrobulbar vessels remained unaffected. Blood pressure and heart rate remained unchanged.Conclusions.Hypervolemic hemodilution has an acute effect on blood flow velocities in the CRA and PCAs in NAION patients. Increased blood flow in the arteries supplying the optic nerve head may lead to a better perfusion in NAION patients. This trial is registered withDRKS00012603.

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