Haft Jonathan W, Alnajjar Osamma, Bull Joseph L, Bartlett Robert H, Hirschl Ronald B
Department of Surgery, University of Michigan Health System, University of Michigan, Ann Arbor, MI 48109, USA.
ASAIO J. 2005 Nov-Dec;51(6):769-72. doi: 10.1097/01.mat.0000186495.70657.fc.
Artificial lungs may serve as transplant alternatives to patients with respiratory failure. To provide a pulmonary replacement, the device cannot significantly alter right ventricular afterload. We sought to characterize cardiac load using a prototype artificial lung as a pulmonary replacement. An artificial lung was implanted into 13 adult sheep, 7 using a noncompliant original prototype and 6 using a modified device with a compliance chamber. Inflow was from the pulmonary artery and outflow into the left atrium. Pulmonary impedance was determined and pulse wave reflections analyzed. Resistance was similar in the original prototype artificial lung and in the native pulmonary circulation (3.0 vs 3.2 Woods units, p = 0.5). First harmonic impedance was significantly increased in the original prototype artificial lung (0.4 vs 5.9 Woods units, p < 0.01). High-amplitude pulse wave reflections were identified and right ventricular function was altered. The addition of compliance to the artificial lung reduced impedance at the first harmonic (5.9 vs 1.9 Woods units, p < 0.01), decreased the amplitude of pulse wave reflections, and normalized right ventricular function. A low-resistance but noncompliant artificial lung increases pulmonary impedance and alters right ventricular function. Addition of a compliance chamber reduces pulse wave reflections and normalizes ventricular function.
人工肺可作为呼吸衰竭患者的移植替代方案。为提供肺替代功能，该装置不能显著改变右心室后负荷。我们试图使用一种原型人工肺作为肺替代物来表征心脏负荷。将人工肺植入13只成年绵羊体内，7只使用不顺应性的原始原型，6只使用带有顺应腔的改良装置。血流从肺动脉流入，经人工肺后流入左心房。测定肺阻抗并分析脉搏波反射。原始原型人工肺的阻力与天然肺循环中的阻力相似（3.0对3.2伍兹单位，p = 0.5）。原始原型人工肺的一次谐波阻抗显著增加（0.4对5.9伍兹单位，p < 0.01）。识别出高振幅脉搏波反射，且右心室功能发生改变。给人工肺增加顺应性可降低一次谐波处的阻抗（5.9对1.9伍兹单位，p < 0.01），降低脉搏波反射的幅度，并使右心室功能恢复正常。低阻力但不顺应的人工肺会增加肺阻抗并改变右心室功能。增加一个顺应腔可减少脉搏波反射并使心室功能恢复正常。
