title: In vitro and in vivo heat dissipation of an electrohydraulic totally implantable artificial heart.
abstract: The authors evaluated the heat transfer characteristics of an electrohydraulic totally implantable artificial heart (EH-TAH) developed at our institute. In three in vitro experiments, the heat dissipation of the EH-TAH was investigated. First, the EH-TAH was connected to a closed mock circuit filled with 1 L of saline, and driven at an input power of 20 W. The estimated heat conducted to the blood was approximately 10.3 W, which was almost half of the input power. Second, we simulated heat transfer with the circulation of a calf by using a heat exchanger. The amount of heat dissipating directly from the EH-TAH surface was calculated to be 10 W. Third, the temperature of the actuator examined with thermography was found to be almost uniform, and no prominent high temperature area was observed. In an in vivo study, the EH-TAH was implanted for 10 days in a calf weighing 62 kg. The input power was 18 +/- 2 W, the temperature of the actuator-tissue contacting surface was 39.4 +/- 0.8 degrees C, and that of the pump blood chamber was 39.8 +/- 0.4 degrees C. This slight temperature elevation was thought to be attributable to heat dissipation to the blood. On histologic study of the chest wall and the lung in contact with the actuator, vascularized connective tissue envelopes were observed, but unfavorable side effects, such as tissue necrosis, were not observed. These results suggest that the thermal effect of this system is acceptable at the input power used.
authors.affiliation: Department of Artificial Organs, National Cardiovascular Center Research Institute, Osaka, Japan.
authors.forename: S
authors.initials: S
authors.lastname: Endo
authors.forename: T
authors.initials: T
authors.lastname: Masuzawa
authors.forename: E
authors.initials: E
authors.lastname: Tatsumi
authors.forename: Y
authors.initials: Y
authors.lastname: Taenaka
authors.forename: T
authors.initials: T
authors.lastname: Nakatani
authors.forename: T
authors.initials: T
authors.lastname: Ohno
authors.forename: Y
authors.initials: Y
authors.lastname: Wakisaka
authors.forename: T
authors.initials: T
authors.lastname: Nishimura
authors.forename: Y
authors.initials: Y
authors.lastname: Takewa
authors.forename: M
authors.initials: M
authors.lastname: Nakamura
authors.forename: K
authors.initials: K
authors.lastname: Takiura
authors.forename: Y S
authors.initials: YS
authors.lastname: Sohn
authors.forename: H
authors.initials: H
authors.lastname: Takano
mesh_terms: D000818:Animals; D001698:Biomedical Engineering; D002417:Cattle; D005069:Evaluation Studies as Topic; D006354:Heart, Artificial; D006358:Hot Temperature / Q000009:adverse effects; D006801:Humans; D066298:In Vitro Techniques; D011474:Prosthesis Design