Clinic for Thoracic and Cardiovascular Surgery, Heart and Diabetes Center NRW, Ruhr University Bochum, Bad Oeynhausen, Germany.
Eur J Cardiothorac Surg. 2014 Jan;45(1):69-74. doi: 10.1093/ejcts/ezt257. Epub 2013 May 10.
Miniaturized cardiopulmonary bypass (MCPB) is increasingly used in cardiac surgery, because it can lower clinically significant complications such as systemic inflammatory response, haemolysis and high transfusion requirements. A limitation of MCPB is the risk of excessive negative pressure in the venous line during volume depletion, probably leading to gaseous microembolism.
In an experimental study with 24 pigs, we compared conventional open cardiopulmonary bypass (CCPB group, n = 11) with MCPB (n = 13). The same pump and identical tubing materials were used in both groups. Primary endpoints were pressure values in the venous line and the right atrium as well as the amount of air bubbles >500 µm. Secondary endpoints were biochemical parameters of systemic inflammatory response, ischaemia, haemodilution and haemolysis.
Nearly 20% of venous pressure values were below -150 mmHg and approximately 10% of the right atrial pressure values were below -100 mmHg in the MCPB group, during the experiment. No such low values were observed in the CCPB group. In addition, the number of large arterial air bubbles was higher in the MCPB group compared with the CCPB group (mean ± standard deviation [SD]: 13 444 ± 5709 vs 0.9 ± 0.6, respectively; P < 0.001). Bubble volume was also significantly larger during MCPB compared with CCPB (mean ± SD: 1522 ± 654 vs 4.1 ± 2.5 µl, respectively; P < 0.001). Blood levels of interleukin-6, free haemoglobin and creatine kinase were significantly higher in the CCPB group compared with the MCPB group.
Despite the benefits of MCPB regarding systemic inflammatory response and haemolysis, this technique is associated with excessive negative venous line pressures and a significant increase in the number and volume of arterial air bubbles compared with CCPB. Mini-perfusion systems and the management of MCPB require further refinements to avoid such adverse effects.
微创体外循环（MCPB）在心脏外科中越来越多地被应用，因为它可以降低全身性炎症反应、溶血和高输血需求等具有临床意义的并发症。MCPB 的一个局限性是在容量不足期间静脉管路中可能出现的过度负压风险，这可能导致气体微栓塞。
在一项有 24 头猪的实验研究中，我们比较了常规开放式体外循环（CCPB 组，n = 11）与 MCPB（n = 13）。两组均使用相同的泵和相同的管路材料。主要终点是静脉管路和右心房的压力值以及 >500 µm 的气泡数量。次要终点是全身炎症反应、缺血、血液稀释和溶血的生化参数。
在 MCPB 组的实验过程中，近 20%的静脉压力值低于-150mmHg，约 10%的右心房压力值低于-100mmHg。在 CCPB 组未观察到如此低的压力值。此外，MCPB 组的大动脉气泡数量明显高于 CCPB 组（平均值±标准差[SD]：13444±5709 与 0.9±0.6，分别；P <0.001）。与 CCPB 相比，MCPB 时的气泡体积也明显更大（平均值±SD：1522±654 与 4.1±2.5 µl，分别；P <0.001）。与 MCPB 组相比，CCPB 组的白细胞介素-6、游离血红蛋白和肌酸激酶的血液水平明显更高。
尽管 MCPB 具有降低全身性炎症反应和溶血的优势，但与 CCPB 相比，该技术与过度的负静脉管路压力以及动脉气泡数量和体积的显著增加相关。微创灌注系统和 MCPB 的管理需要进一步改进，以避免此类不良影响。
