Toomasian J M, McCarthy J P
Department of Cardiothoracic Surgery, Stanford University Medical Center, California, USA.
Perfusion. 1998 Mar;13(2):137-43. doi: 10.1177/026765919801300209.
Extrathoracic cardiopulmonary bypass is used in special situations when normal access to the right atrium and aorta is difficult or not practicable. Femero-femoral bypass using gravity drainage is effective for partial cardiopulmonary support, but cannot usually provide adequate venous drainage for full circulatory support. Kinetic assisted venous drainage (KAVD) is the process of applying a controlled suction on the venous line with a kinetic pump to augment venous drainage. KAVD has been used in 50 patients where femero-femoral bypass was selected as the mode of circulatory support. These cases included: redo-operations with significant sternal adhesions (15), minimally invasive port-access cardiac surgery (12), haemodynamic instability (10), left thoracotomy (10), and others (3). In 11 cases, a second venous catheter was added because of protocol. No appreciable increase in venous return occurred with the addition of a second drainage catheter. All patients were adequately supported and a 20-40% increase in venous return was observed once KAVD was implemented. A wide variety of different venous catheters have been used with KAVD. Optimal use relates to having a thin-walled catheter with multiple side holes, not exerting an excessive negative pressure with the pump and positioning the catheter tip at the right atrio-superior vena cava junction. Optimal catheter tip placement is enhanced by using transoesophageal echocardiography. KAVD is best regulated by measuring the siphon generated by the kinetic pump. When the inlet pressure is properly monitored and controlled, KAVD can provide adequate venous drainage to completely support the circulation on a single femoral venous cannula.
当难以或无法正常进入右心房和主动脉时，在特殊情况下会使用胸外心肺转流。采用重力引流的股-股旁路对部分心肺支持有效，但通常不能为完全循环支持提供足够的静脉引流。动力辅助静脉引流（KAVD）是指用动力泵在静脉管路施加可控吸力以增加静脉引流的过程。KAVD已应用于50例选择股-股旁路作为循环支持模式的患者。这些病例包括：有严重胸骨粘连的再次手术（15例）、微创端口入路心脏手术（12例）、血流动力学不稳定（10例）、左胸廓切开术（10例）以及其他情况（3例）。根据方案，11例患者加用了第二根静脉导管。加用第二根引流导管后静脉回流量没有明显增加。所有患者均得到充分支持，实施KAVD后观察到静脉回流量增加了20%-40%。KAVD使用了多种不同的静脉导管。最佳应用是使用带有多个侧孔的薄壁导管，泵不施加过大负压，并将导管尖端置于右心房-上腔静脉交界处。通过经食管超声心动图可优化导管尖端的放置。通过测量动力泵产生的虹吸作用可最佳调节KAVD。当入口压力得到适当监测和控制时，KAVD可通过单根股静脉插管提供足够的静脉引流以完全支持循环。
