De Somer Filip M J J, Vetrano Maria R, Van Beeck Jeroen P A J, Van Nooten Guido J
Heart Centre, Universitair Ziekenhuis Gent, Gent, Belgium.
Interact Cardiovasc Thorac Surg. 2010 Jun;10(6):995-1001. doi: 10.1510/icvts.2009.229088. Epub 2010 Mar 2.
Gaseous microemboli (GME) are a cause of neurocognitive deficit postcardiac surgery with cardiopulmonary bypass. However, the measurement of microbubbles during cardiopulmonary bypass is not easy, because blood is an opaque fluid and contains microparticles. Recently, two new microbubble counters, the Gampt BC200 and the emboli detection and classification (EDAC) quantifier, were developed for use during cardiac surgery. The accuracy of both devices was validated against industrial standards.
A clear blood analogue (30%/70% glycerol-water) was pumped, by means of a rollerpump out of a partially filled arterial line screen filter with a nominal pore size of 20 microm. Downstream the pump, all test sensors and an optical cuvette, were inserted in a vertically mounted 3/8 inch tubing. Measurements were taken at flows of 405, 1080, 3000 and 6000 ml/min. Backlight shadowgraphy and optical counting were used as industrial reference techniques for measuring size and counts.
On average the EDAC quantifier underestimates average bubble diameter by 35+/-1%, 13+/-8%, 71+/-7% and 33+/-4% at 405, 1080, 3000 and 6000 ml/min, respectively. The Gampt BC200 has good sizing agreement at 1080 ml/min (+5+/-17%) and 3000 ml/min (+33+/-6%) but overestimates average diameter by 220+/-40% and 295+/-49% at 405 and 6000 ml/min, respectively. Both devices only partially count the number of microbubbles at higher flows. At 3 l/min the EDAC counts 38%, the Gampt 18% of total counts and at 6 l/min both the EDAC and Gampt only count 3% of total counts.
Both the EDAC and Gampt can be used in a clinical setting for monitoring basal GME production. However, both devices have some major limitations when used for studying 'worst case' scenarios. One should take great caution when correlating measured data with neurocognitive outcome. Finally, results obtained by one device in a first study cannot be compared nor exchanged with results from the other device in a second study.
气体微栓子（GME）是心脏手术后体外循环导致神经认知功能障碍的一个原因。然而，在体外循环期间测量微泡并不容易，因为血液是一种不透明的液体且含有微粒。最近，开发了两种新的微泡计数器，即Gampt BC200和栓子检测与分类（EDAC）定量仪，用于心脏手术期间。两种设备的准确性均已根据行业标准进行了验证。
通过滚轴泵从部分填充的动脉管路筛网过滤器中抽出一种透明血液模拟物（30%/70%甘油 - 水），该过滤器的标称孔径为20微米。在泵的下游，所有测试传感器和一个光学比色皿被插入垂直安装的3/8英寸管道中。在405、1080、3000和6000毫升/分钟的流速下进行测量。背光照相术和光学计数被用作测量尺寸和数量的行业参考技术。
平均而言，在405、1080、3000和6000毫升/分钟时，EDAC定量仪分别将平均气泡直径低估35±1%、13±8%、71±7%和33±4%。Gampt BC200在1080毫升/分钟（+5±17%）和3000毫升/分钟（+33±6%）时尺寸测量一致性良好，但在405和6000毫升/分钟时分别将平均直径高估220±40%和295±49%。在较高流速下，两种设备都只能部分计数微泡数量。在3升/分钟时，EDAC计数为总数的38%，Gampt为18%；在6升/分钟时，EDAC和Gampt都仅计数总数的3%。
EDAC和Gampt均可用于临床环境中监测基础GME产生情况。然而，在用于研究“最坏情况”时，两种设备都有一些主要局限性。在将测量数据与神经认知结果相关联时应格外谨慎。最后，在第一项研究中由一种设备获得的结果与第二项研究中另一种设备的结果既不能比较也不能互换。
