Adaptation of Tissue to a Chronic Heat Load

Davies, Charles R.; Fukumura, Fumio; Fukamachi, Kiyotaka; Muramoto, Kazuhiro; Himley, Stephen; Massiello, Alex; Chen, Ji‐feng; Harasaki, Hiroaki

doi:10.1097/00002480-199407000-00053

Cited by 27 publications

(20 citation statements)

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“…Heat flow into the surrounding tissue is primarily through capillary perfusion (36) and can be represented using a convection coefficient at the boundary. In this study by Davies et al, heating devices with temperature sensors were implanted in calves adjacent to lung and muscle tissue for a period of 7 weeks.…”

Section: Design Resultsmentioning

confidence: 99%

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

et al. 2017

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This article provides an overview of the design challenges associated with scaling the low-shear pulsatile TORVAD ventricular assist device (VAD) for treating pediatric heart failure. A cardiovascular system model was used to determine that a 15 ml stroke volume device with a maximum flow rate of 4 L/min can provide full support to pediatric patients with body surface areas between 0.6 to 1.5 m2. Low shear stress in the blood is preserved as the device is scaled down and remains at least two orders of magnitude less than continuous flow VADs. A new magnetic linkage coupling the rotor and piston has been optimized using a finite element model (FEM) resulting in increased heat transfer to the blood while reducing the overall size of TORVAD. Motor FEM has also been used to reduce motor size and improve motor efficiency and heat transfer. FEM analysis predicts no more than 1°C temperature rise on any blood or tissue contacting surface of the device. The iterative computational approach established provides a methodology for developing a TORVAD platform technology with various device sizes for supporting the circulation of infants to adults.

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Section: Design Resultsmentioning

confidence: 99%

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

et al. 2017

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“…The actuator temperature only exceeded the body temperature by approximately 2°C, thereby meeting our design goal of a tissue-contacting temperature not exceeding more than 4°C of body temperature to avoid detrimental biologic effects by chronic tissue heating. 9 All blood-contacting surfaces of the pumps in the experiments lasting 90 days and 10 days were clean and without any depositions in the absence of postoperative anticoagulation therapy. The blood compatibility results of these implants are fully consistent with previous studies performed on TAH programs at the CCF.…”

Section: Discussionmentioning

confidence: 99%

In Vivo Performance and Biocompatibility of the MagScrew Ventricular Assist Device

Schenk¹,

Weber²,

Luangphakdy³

et al. 2003

ASAIO Journal

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Currently available ventricular assist devices (VADs) have limitations in long-term durability and blood compatibility. We evaluated a prototype of a pulsatile MagScrew VAD for in vivo hemodynamic performance and biocompatibility. The device is composed of an actuator, blood pump housing, diaphragm, pusher plate, and bioprosthetic valves. Its protein-coated ("biolized") blood-contacting surface inhibits clot formation. Forces between moving parts of the actuator are transmitted magnetically, eliminating a primary source of friction and wear. The pump fills passively and is highly preload sensitive. The device was implanted into three calves for 90, 10, and 57 days, respectively. No anticoagulants were given postoperatively. The device functioned without technical problems during the entire course of each experiment, with mean device flow ranging between 5.4 and 9.0 L/min. Autopsy of the first two calves revealed no sign of embolization and clean blood-contacting surfaces of the devices. The third experiment was complicated by a prosthetic valve endocarditis with infectious embolization, and a few small depositions were found in the pump. In conclusion, the MagScrew VAD has demonstrated a high level of performance and biocompatibility in three calves studied for 10-90 days. Vigorous development is in progress to bring this device to preclinical readiness and thus provide surgeons with the VAD of choice for permanent implantation.

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“…It has been investigated in depth by researchers at Case Western Reserve University (Saidel, 2001;Davies et al, 1994;Liu et al, 2003;Seese et al, 1998;Okazaki et al, 1997). The experimental data related power consumption to surface temperature increase.…”

Section: Implant Heatingmentioning

confidence: 99%

Design Considerations of Biomedical Telemetry Devices

Nikita

2014

Handbook of Biomedical Telemetry

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Adaptation of Tissue to a Chronic Heat Load

Cited by 27 publications

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Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

Scaling the Low-Shear Pulsatile TORVAD for Pediatric Heart Failure

In Vivo Performance and Biocompatibility of the MagScrew Ventricular Assist Device

Design Considerations of Biomedical Telemetry Devices

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