Evaluation of the sterility and oxygenator performance of an ECMO circuit after 30 days ofstorage
Ryosuke Kasai（Tokyo University of Technology Department of Clinical Engineering Schoolof Health Sciences）, Mitsuhiro Okazaki, Yukako Tanaka, Yuki Ando, Tetsuya Shimamine,
Fuminori Kamijo, Naoki Kawata, Aya Murata, Masaru Inoue, Hiroaki Kawano, KazuhikoShinohara, Kohei Tanaka
Abstract
The ELSO General Guidelines for ECLS Cases 2017 recommend an ECMO circuit storage
period of up to 30 days after filling the circuit. However, no studies have been conducted on
ECMO circuits containing artificial lungs with silicone membrane and porous polypropylene
hollow fiber for support. Also, no Japanese standards have been formulated for the storage
period of filled ECMO circuits. The main problems during the storage period after filling theECMO circuits are maintaining sterility in the circuit and maintaining gas exchange
performance in the artificial lungs. Therefore, we evaluated the sterility and maintenance ofartificial lung performance in ECMO circuits containing artificial lungs with silicone
membranes having porous polypropylene hollow fiber as support during 30 days of storage.
The ECMO circuit used was the MERA Exceline circuitHP2 “#ST SOLAS23H-CSP3 Hepa”（ SENKO MEDICAL INSTRU MENT Mfg. CO., LTD. ） . The ECMO circuits werecategorized into a dry group （n＝5）, which were kept in an unfilled condition, and a wetgroup （n＝5）, which were filled and primed. Bacteriological tests included bacterial culture
evaluation using a BHI medium and endotoxin evaluation. Furthermore, oxygen transfer,carbon dioxide transfer, and pressure drop were assessed as part of the artificial lungperformance evaluation. As a result, all samples showed no turbidity in the medium, indicating
no bacterial growth, and endotoxin levels were below the detection limit. No degradation of
artificial lung performance was observed, and their gas exchange capacity specifications weremet. In this study, ECMO circuits having silicone membranes and porous polypropylene
hollow fiber supports could maintain sterility even after 30 days of storage without affecting
blood gas exchange performance specifications, which would become inapplicable otherwise.
The results of this study demonstrated that an ECMO circuit containing artificial lungs
constructed using silicone membrane and porous propylene hollow fiber can be stored for 30days after filling.
Key words：ECMO, aseptic, BHI culture, endotoxin

Investigation of a method for the electrical measurement of venous reservoir blood volume
Atsushi Nakamura（Department of Clinical Engineering, Faculty of Health Sciences, KyorinUniversity）, Eiki Kogure, Masaru Inoue, Katsuyuki Kuwana
Abstract
Blood volume in the venous reservoir （ VR） is an important parameter that should becontinuously monitored in patients with a cardiopulmonary bypass. In this study, weinvestigated the effects of measurement frequency, hematocrit（Ht）, and blood volume on
the capacitance（Cs）of blood present in the venous reservoir by utilizing electrical propertiesof polycarbonate, a material used in VR. In Experiment 1, two electrodes were attached to theVR wall surface and the capacitance Cs［F］between the electrodes at each liquid level wasmeasured at frequencies from 100kHz to 1MHz. VR was filled with physiological saline orbovine blood（Ht 20％, 25％, and 30％）. In Experiment 2, Cs values were measured at afrequency of 1MHz by attaching an electrode to a cylindrical container and filling it withphysiological saline. The results of Experiment 1 showed that the Cs value increased withraising liquid level, with increases of 1.30pF/cm（saline）, 1.26pF/cm（Ht 20％）, 1.28pF/cm（Ht 25％）and 1.13pF/cm（Ht 30％）at a frequency of 1MHz. In Experiment 2, Cs increasedby 1.41pF/cm. The frequency range of 800kHz to 1MHz was found to be stable with minimal
effects on the blood, suggesting that the frequency can be used for continuous measurementof the blood volume in VRs of various shapes.
Key words：cardiopulmonary bypass，venous reservoir，level sensor，reservoir volume，
automation