Fukamachi K, Fukumura F, Kiraly R J, Massiello A L, Chen J F, Himley S, Davies C, Muramoto K, Olsen E, Golding L A
Department of Biomedical Engineering, Cleveland Clinic Foundation, OH 44195.
ASAIO J. 1993 Jul-Sep;39(3):M419-22. doi: 10.1097/00002480-199307000-00053.
Hemodynamic changes with posture, sitting versus standing, were analyzed in five Holstein calves with the Cleveland Clinic-Nimbus TAH. This total artificial heart (TAH) has a left master alternate control mode that adjusts the pump rate and consequently pump flow proportional to the pulmonary venous return to the left pump (AUTO period). However, in this series of experiments, the pump reached its maximum beat rate within 1-5 days post operatively, after which pump flow could not increase (MAX period). Hemodynamic parameters (RAP, LAP, PAP, AoP, and pump flow) were obtained every 15-20 min throughout the experiments for as long as 120 days and averaged for each posture for each period. During the AUTO period, the flow while standing was significantly higher than that while sitting (standing: 8.7 +/- 0.2 L/min; sitting: 7.5 +/- 0.4 L/min; p < 0.05), and the systemic vascular resistance (SVR) was significantly lower (standing: 895 +/- 93 dyne.sec.m-5; sitting: 1,041 +/- 124 dyne.sec.m-5; p < 0.05). During the MAX period, the AoP and SVR standing were significantly lower than those sitting (AoP standing: 91 +/- 7 mmHg; AoP sitting: 98 +/- 7 mmHg; p < 0.05; SVR standing: 652 +/- 75 mmHg; SVR sitting: 730 +/- 96 mmHg; p < 0.05). The Cleveland Clinic-Nimbus TAH responded well to these changes in position, increasing pump flow and maintaining the AoP during the AUTO period.
对五头植入克利夫兰诊所-宁巴斯全人工心脏（TAH）的荷斯坦小牛进行了坐姿与站姿时血流动力学变化的分析。这种全人工心脏（TAH）具有左主交替控制模式，可根据左心室肺静脉回流量调节泵速，进而调节泵流量（自动模式）。然而，在这一系列实验中，术后1至5天内泵就达到了最大搏动率，此后泵流量无法再增加（最大模式）。在长达120天的实验过程中，每隔15至20分钟获取一次血流动力学参数（右房压、左房压、肺动脉压、主动脉压和泵流量），并对每个时期每种姿势的参数求平均值。在自动模式期间，站立时的流量显著高于坐姿时（站立：8.7±0.2升/分钟；坐姿：7.5±0.4升/分钟；p<0.05），全身血管阻力（SVR）显著更低（站立：895±93达因·秒·米⁻⁵；坐姿：1041±124达因·秒·米⁻⁵；p<0.05）。在最大模式期间，站立时的主动脉压和全身血管阻力显著低于坐姿时（站立时主动脉压：91±7毫米汞柱；坐姿时主动脉压：98±7毫米汞柱；p<0.05；站立时全身血管阻力：652±75毫米汞柱；坐姿时全身血管阻力：730±96毫米汞柱；p<0.05）。克利夫兰诊所-宁巴斯全人工心脏对这些体位变化反应良好，在自动模式期间增加了泵流量并维持了主动脉压。
