T. Rath et al.: J Extra Corpor Technol 2026, 58, 19 – 31 21
Figure
1. Circuit description. Schematic of the laboratory-based( in-vitro) cardiopulmonary bypass circuit. Bovine blood was recirculated from the“ test” cardiotomy reservoir, past the“ venous” GME sensor, to the centrifugal pump, where it was pumped through the oxygenator. Blood flowed past the“ arterial” GME sensor and into the“ patient” reservoir, where it drained back into the“ test” reservoir after passing through the“ recirculation” GME probe. Suctioned blood was pumped from the“ patient” reservoir and into the suction port of the test reservoir by the roller suction pump. This suctioned blood was aerated by another roller pump that entrained room air into the suction blood flow.
Table 1. Specifications of membrane oxygenators and venous reservoirs tested in this study.
|
Medtronic affinity fusion™ |
LivaNova SORIN inspire™8F |
Terumo CAPIOX Ò FX25 advance |
Oxygenator type |
Microporous polypropylene hollow fiber |
Microporous polypropylene hollow fiber |
Microporous polypropylene hollow fiber |
Oxygenator filtration |
25 lm progressive depth |
38 lm screen |
32 lm screen |
Oxygenator maximum blood flow rate |
7.0 L / min |
8.0 L / min |
7.0 L / min |
Reservoir type( Hardshell) |
Dual chamber |
Dual chamber |
Dual chamber |
Reservoir capacity |
4,500 mL |
4,500 mL |
4,000 mL |
Reservoir minimum operating level |
200 mL @ 7 L / min |
150 mL |
150 mL |
Reservoir maximum blood flow rate |
7.0 L / min |
8.0 L / min |
7.0 L / min |
Cardiotomy reservoir filtration |
30 lm |
41lm |
47 lm |
Oxygenator / reservoir coating |
Balance™ |
PHISIO™ |
Xcoating™ |
Medtronic information – accessed 7 / 31 / 2024, LivaNova information – accessed 7 / 30 / 2024, Terumo information – accessed 7 / 30 / 2024.
Post-oxygenator line pressure was monitored and maintained at 180 mmHg by placing a partial clamp on the arterial line to simulate arterial cannulation. A filtered gas line delivered 100 % tanked oxygen to the oxygenator during the trials.
Priming procedure
The circuit was flushed with 4 L of carbon dioxide for 5 min before priming. Next, it was primed with 2 L of crystalloid( Normosol-R). It circulated for 10 min through a 0.2-micron pre-bypass filter( Pall Corporation Ò, Portsmouth, PA) to remove particulates and residual air.
Five liters of fresh bovine blood were collected for each trial from a local slaughterhouse and mixed with 30,000 IU of heparin to prevent clotting during transportation. Upon arrival at our facility, we measured the activated clotting time( Hemochron Signature Elite, Werfen Bedford, MA, USA) and the spun hematocrit( Model CMH30, UNICO, Dayton, NJ, USA).
After removing air and the pre-bypass filter from the circuit, a calculated volume of filtered and anticoagulated bovine blood was introduced to the test circuit while simultaneously displacing the same crystalloid volume to achieve a goal hematocrit of 25 %. Additional heparin was administered to maintain an activated clotting time of over 480 s. Trials were started within