Control of a total artificial heart using mixed venous oxygen saturation.
We developed a control of the total artificial heart (TAH) using mixed venous oxygen saturation (SvO2). With this method, the TAH output was controlled by automatically adjusting drive parameters in response to changes in measured SvO2. The feasibility and validity of this method were evaluated in a series of treadmill exercise tests using a calf implanted with a pneumatic TAH. The cardiac output (CO) and SvO2 were measured with an ultrasonic flowmeter and an oximetric catheter, respectively. The calf performed graded exercise under a fixed drive control mode (fixed mode), in which the drive parameters were unchanged throughout the treadmill test, and under the SvO2 based control mode (SvO2 mode). The calf could go to Stage 6 in both modes, but the maximal oxygen consumption in the SvO2 mode was 1.5 times as large as that of the fixed mode. Compared with the fixed mode, CO was increased effectively in the SvO2 mode, and the capacity for exercise was augmented. When considering the relationship between oxygen consumption and oxygen delivery, it was revealed that the CO in the SvO2 mode responded more adequately to the recipient's oxygen demand than that in the fixed mode. We conclude that this SvO2 based control method is feasible and physiologically effective.
Nakamura
M
M
Department of Artificial Organs, National Cardiovascular Center Research Institute, Suita, Osaka, Japan.
Masuzawa
T
T
Tatsumi
E
E
Taenaka
Y
Y
Ohno
T
T
Nakamura
T
T
Zhang
B
B
Kakuta
Y
Y
Nakatani
T
T
Takano
H
H
D000818:Animals; D002302:Cardiac Output; D002417:Cattle; D005080:Exercise Test; D006354:Heart, Artificial; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D014655:Vascular Resistance
D010100:Oxygen