Carbon Dioxide Flush of an Integrated Minimized Perfusion Circuit Prior to Priming Prevents Spontaneous Air Release Into the Arterial Line During Clinical Use

Abstract

Recently, an oxygenator with an integrated centrifugal blood pump (IP) was designed to minimize priming volume and to reduce blood foreign surface contact even further. The use of this oxygenator with or without integrated arterial filter was compared with a conventional oxygenator and nonintegrated centrifugal pump. To compare the air removal characteristics 60 patients undergoing coronary artery bypass grafting were alternately assigned into one of three groups to be perfused with a minimized extracorporeal circuit either with the conventional oxygenator, the oxygenator with IP, or the oxygenator with IP plus integrated arterial filter (IAF). Air entering and leaving the three devices was measured accurately with a bubble counter during cardiopulmonary bypass. No significant differences between all groups were detected, considering air entering the devices. Our major finding was that in both integrated devices groups incidental spontaneous release of air into the arterial line in approximately 40% of the patients was observed. Here, detectable bolus air (>500 µm) was shown in the arterial line, whereas in the minimal extracorporeal circulation circuit (MECC) group this phenomenon was not present. We decided to conduct an amendment of the initial design with METC-approval. Ten patients were assigned to be perfused with an oxygenator with IP and IAF. Importantly, the integrated perfusion systems used in these patients were flushed with carbon dioxide (CO ) prior to priming of the systems. In the group with CO flush no spontaneous air release was observed in all cases and this was significantly different from the initial study with the group with the integrated device and IAF. This suggests that air spilling may be caused by residual air in the integrated device. In conclusion, integration of a blood pump may cause spontaneous release of large air bubbles (>500 µm) into the arterial line, despite the presence of an integrated arterial filter. CO flushing of an integrated cardiopulmonary bypass system prior to priming may prevent spontaneous air release and is strongly recommended to secure patient safety.

2019 EACTS/EACTA/EBCP guidelines on cardiopulmonary bypass in adult cardiac surgery

“…Two small studies showed a statistically significant reduction of GME. 135,136 In order to obtain the CO 2 content at 97e98% in the oxygenator, a single-centre study suggested that~5 min of flushing is necessary, whereas a more extended duration did not increase the value significantly. 135 Another important finding was that a CO 2 flush reduced GME in the prime and not in the arterial filtration.…”

Generation of microbubbles in extracorporeal life support and assessment of new elimination strategies

“…Additionally, a specific micro bubble counter (BCC 200; GAMPT mbh, Merseburg, Germany) with two Doppler effect‐based ultrasound probes was used for MB detection, as described elsewhere . The device is able to count as well as to measure the dimensions of the MB flowing by.…”

“…Additionally, a specific micro bubble counter (BCC 200; GAMPT mbh, Merseburg, Germany) with two Doppler effect-based ultrasound probes was used for MB detection, as described elsewhere. 12 The device is able to count as well as to measure the dimensions of the MB flowing by. Depending on the specific test run, the probes were either placed before and after the centrifugal pump (generation of MB) or before and after the bubble elimination section (evaluation of the elimination strategies).…”

Recent innovations in perfusion and cardiopulmonary bypass for neonatal and infant cardiac surgery

“…These factors serve as potential limitations to the miniaturization of the extracorporeal circuit. Additionally, when determining circuit length and configuration, consideration must be given to include the ability to remove GME and to access the circuit during emergency procedures (36,38).…”