title: Development of a compact wearable pneumatic drive unit for a ventricular assist device.
abstract: The purpose of this study was to develop a compact wearable pneumatic drive unit for a ventricular assist device (VAD). This newly developed drive unit, 20 x 8.5 x 20 cm in size and weighing approximately 1.8 kg, consists of a brushless DC motor, noncircular gears, a crankshaft, a cylinder-piston, and air pressure regulation valves. The driving air pressure is generated by the reciprocating motion of the piston and is controlled by the air pressure regulation valves. The systolic ratio is determined by the noncircular gears, and so is fixed for a given configuration. As a result of an overflow-type mock circulation test, a drive unit with a 44% systolic ratio connected to a Toyobo VAD blood pump with a 70-ml stroke volume achieved a pump output of more than 7 l/min at 100 bpm against a 120 mmHg afterload. Long-term animal tests were also performed using drive units with systolic ratios of 45% and 53% in two Holstein calves weighing 62 kg and 74 kg; the tests were terminated on days 30 and 39, respectively, without any malfunction. The mean aortic pressure, bypass flow, and power consumption for the first calf were maintained at 90 x 13 mmHg, 3.9 x 0.9 l/min, and 12 x 1 W, and those for the second calf were maintained at 88 x 13 mmHg, 5.0 x 0.5 l/min, and 16 x 2 W, respectively. These results indicate that the newly developed drive unit may be used as a wearable pneumatic drive unit for the Toyobo VAD blood pump.
authors.affiliation: The Advanced Medical Engineering Center, National Cardiovascular Center Research Institute, 5-7-1 Fujishiro-dai, Suita, Osaka 565-8565, Japan. honma@ri.ncvc.go.jp
authors.forename: Akihiko
authors.initials: A
authors.lastname: Homma
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Taenaka
authors.forename: Eisuke
authors.initials: E
authors.lastname: Tatsumi
authors.forename: Eiki
authors.initials: E
authors.lastname: Akagawa
authors.forename: Hwansung
authors.initials: H
authors.lastname: Lee
authors.forename: Tomohiro
authors.initials: T
authors.lastname: Nishinaka
authors.forename: Yoshiaki
authors.initials: Y
authors.lastname: Takewa
authors.forename: Toshihide
authors.initials: T
authors.lastname: Mizuno
authors.forename: Tomonori
authors.initials: T
authors.lastname: Tsukiya
authors.forename: Yukihide
authors.initials: Y
authors.lastname: Kakuta
authors.forename: Nobumasa
authors.initials: N
authors.lastname: Katagiri
authors.forename: Isao
authors.initials: I
authors.lastname: Shimosaki
authors.forename: Shigeru
authors.initials: S
authors.lastname: Hamada
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Mukaibayashi
authors.forename: Wataru
authors.initials: W
authors.lastname: Iwaoka
mesh_terms: D000818:Animals; D002417:Cattle; D011211:Electric Power Supplies; D004867:Equipment Design; D006353:Heart-Assist Devices