Analysis of the relationship between left ventricular pressure and motor current for evaluation of native cardiac function during left ventricular support with a centrifugal blood pump
- 54 Downloads
Control of the ventricular assist device (VAD) for native heart preservation should be attempted, and the VAD could be one strategy for dealing with the shortage of donors in the future. In the application of nonpulsatile blood pumps for ventricular assistance from the ventricular apex to the aorta, bypass flow and hence the motor current of the pumps change in response to the ventricular pressure change. Utilizing these intrinsic characteristics of the continuous-flow pumps, in this study we investigated whether motor current could be used as an index for continuous monitoring of native cardiac function. In study 1, a centrifugal blood pump (CFP) VAD was installed between the apex and descending aorta of a mock circulatory loop. In this model, a baseline with a preload of 10 mmHg, afterload of 40 mmHg, and LV systolic pressure of 40 mmHg was used. The pump speed was fixed at 1300, 1500, and 1700 rpm, and LV systolic pressure was increased up to 140 mmHg by steps of 20 mmHg while the changes in LV pressure, motor current, pump flow, and aortic pressure were observed. In study 2, an in vivo experiment was performed using three sheep. A left heart bypass model was created using a centrifugal pump from the ventricular apex to the descending aorta. The LVP was varied through administration of dopamine while the changes in LV pressure, pump flow, and motor current at 1500 and 1700 rpm were observed. An excellent correlation was observed in both in vitro and in vivo studies in the relationship between motor current and LV pressure. In study 1, the correlation coefficients were 0.77, 0.92, and 0.99 for 1300, 1500, and 1700 rpm, respectively. In study 2, they were 0.88 (animal no. 1), 0.83 (animal no. 2), and 0.88 (animal no. 3) for 1500 rpm, and 0.95 (animal no. 2) and 0.93 (animal no. 3) for 1700 rpm. These results suggest that motor current amplitude monitoring could be useful as an index for the control of VAD for native heart preservation.
Key wordsCentrifugal blood pump Native cardiac function Left ventricular (LV) pressure Motor current Bridge to recovery
Unable to display preview. Download preview PDF.
- 1.Kyo S, Tanabe H, Asano H, Ohuchi H, Nogaki H, Ishikawa M, Tokote Y, Koyanagi T, Noda H, Omoto R. Clinical effects of ventricular assist system in end-stage cardiac failure. Advantages of left ventricular blood drainage for recovery from cardiac dysfunction. JJTCVS 2000;48:440–446Google Scholar
- 6.Araki K, Oshikawa M, Anai H, Nakamura K, Satoh M, Yoshihara H, Onitsuka T. Detection and implications of the characteristic points for estimating the assisting condition in a continuous-flow artificial heart—in vitro study. Jpn J Artif Organs 1999;28:388–393Google Scholar
- 7.Oshikawa M, Araki K, Anai H, Nakamura K, Satoh M, Onitsuka T. In vivo evaluation of novel control method for a continuous-flow artificial heart. Jpn J Artif Organs 1999;28:320–325Google Scholar
- 9.Hatoh E, Yuhki A, Iseki M, Nogawa M, Takatani S. Detection of suction and regurgitation of the implantable centrifugal pump based on motor current waveform analysis and its application to the optimization of pump flow. Jpn J Artif Organs 1999;28:345–349Google Scholar
- 10.Hatoh E, Yuhki A, Nogawa M, Kikugawa D, Murakami T, Takatani S. Automatic control of the implantable centrifugal pump based on motor current waveform analysis: system design and its evaluation. Jpn J Artif Organs 2000;29:351–355Google Scholar