title: Continuous monitoring of artificial heart pump performance.
abstract: Continuous monitoring of pump performance is essential and effective for optimal driving of a pulsatile blood pump. The authors contrived a practical method for continuous estimation of blood volume in a pump by measurement of electrical impedance (Z). This method was evaluated with the air-driven, diaphragm type pump. The pump was made from polyurethane and had two metal connectors at the inlet and the outlet ports. Z was measured by charging the alternating current (50 kHz, 0.4 mA) between two connectors as electrodes. In in vitro tests, Z reached maximum value during full-empty and minimum value at full-fill. The blood volume calculated by an empirical equation of Z was linearly related to the real blood volume (r = 0.99). In in vivo tests with goats, pump output estimated by this method was linearly related to pump output measured with an electromagnetic flowmeter and effectively evaluated pump performance. For calibration, this method needed only to measure Z at full-fill. This method was useful as a controller of a full-fill to full-empty drive. It was concluded that this method is a practical estimate of pump performance, even if implantable diaphragm type pumps are used, and easily applicable to any kind of pulsatile pump.
authors.affiliation: National Cardiovascular Center Research Institute, Department of Artificial Organs, Osaka, Japan.
authors.forename: E
authors.initials: E
authors.lastname: Sasaki
authors.forename: T
authors.initials: T
authors.lastname: Nakatani
authors.forename: Y
authors.initials: Y
authors.lastname: Taenaka
authors.forename: H
authors.initials: H
authors.lastname: Noda
authors.forename: E
authors.initials: E
authors.lastname: Tatsumi
authors.forename: H
authors.initials: H
authors.lastname: Akagi
authors.forename: T
authors.initials: T
authors.lastname: Masuzawa
authors.forename: M
authors.initials: M
authors.lastname: Goto
authors.forename: M
authors.initials: M
authors.lastname: Sakaki
authors.forename: Y
authors.initials: Y
authors.lastname: Matsuo
mesh_terms: D000818:Animals; D001810:Blood Volume / Q000502:physiology*; D002302:Cardiac Output / Q000502:physiology*; D006041:Goats; D006354:Heart, Artificial; D008955:Models, Cardiovascular; D008991:Monitoring, Physiologic / Q000295:instrumentation*; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D013318:Stroke Volume / Q000502:physiology