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. 2005 Sep;37(3):256-64.

Gaseous microemboli and the influence of microporous membrane oxygenators

Heinz-H Weitkemper  1 , Bernd Oppermann, Andreas Spilker, Hermann-J Knobl, Reiner Körfer
Affiliations

Gaseous microemboli and the influence of microporous membrane oxygenators

Heinz-H Weitkemper et al. J Extra Corpor Technol. 2005 Sep.

Abstract

Gaseous microemboli (GME) are still an unsolved problem of extracorporeal circuits. They are associated with organ injury during cardiopulmonary bypass. Microbubbles of different sizes and number are generated in the blood as the result of different components of the extracorporeal circuit as well as surgical maneuvers. The aim of our study was to observe the behavior of microporous membrane oxygenators to GME in the daily use and in an in vitro model. For the detection of microbubbles, we used a two-channel ultrasonic bubble counter based on 2-MHz Doppler-System with special ultrasound probes. The amount and size of GME were monitored before and after membrane. In 28 scheduled cases with 3 different oxygenators and variability of surgical procedures, we observed the bubble activity in the extracorporeal circuit. In addition, we used an in-vitro model to study the ability of six different oxygenators by removing air in various tests. The oxygenators tested were manufactured with different membrane technologies. The results of our investigations showed varying membrane design lead to a partial removal of GME as well as a change in size and numbers of microbubbles.

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Conflict of interest statement

The senior author has stated that authors have reported no material, financial or other relationship with any healthcare-related business or other entity whose products or services are discussed in this paper.

Figures

Figure 1.
Figure 1.
Bubble detection probe placed on the venous line of the circuit.
Figure 2.
Figure 2.
Diagram of the “closed” circuit for the in vivo study. Bubble detection probes were placed in front and behind the oxygenator.
Figure 3.
Figure 3.
Cross-section of present membrane oxygenators with various flow patterns.
Figure 4.
Figure 4.
Circuit set-up of the in vitro trial.
Figure 5.
Figure 5.
Recording of the bubble recorder monitor.
Figure 6.
Figure 6.
Reduction rate in percent of the in vivo group in relation to bubble size.
Figure 7.
Figure 7.
Time course of CABG procedure. Every peak is related with manipulation, which generates bubbles. Bubble activity can be observed in front and behind the oxygenator.
Figure 8.
Figure 8.
Reduction rate in vivo group of the used oxygenator in total.
Figure 9.
Figure 9.
Histogram of bubble activity in front and behind the oxygenator related to their size.
Figure 10.
Figure 10.
Reduction rate in percent of the in vitro group in relation to bubble size.
Figure 11.
Figure 11.
Reduction rate in vitro group of the used oxygenator in total.
See this image and copyright information in PMC

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