SEMI-AUTOMATIC EVASION OF SUCKING PHENOMENON ON EXRTACORPOREAL MEMBRANE OXYGENATOR (ECMO) BASED ON MOTOR CURRENT:

We previously reported that motor current waveform (MCW) of a centrifugal pump had downward spikes simultaneously with the instant stop of pump flow due to over-support, sucking phenomenon. The objective of this study was to evaluate the feasibility of automatic pump speed controlling for ECMO based on motor current, preventing from the sucking phenomenon. Five dogs (mean 13.7 kg) were used. Inflow cannula (18 Fr.) was put into the inferior vena cava via right thoracotomy and outflow cannula (14 Fr.) was into the left femoral artery. We produced and examined the semi-automatic sucking evasion program. The program monitored MCWs to search the downward spikes as a sucking waveform (SW), and immediately decreased the pump speed until the SW vanished. The program could pick up 92.2 % of all SWs. The reaction time was 5 to 5 seconds to escape from severe sucking completely. In 5 cases of 3-hour assistance (mean pump flow: 0.85 +/− 0.26 L/min), the program could detect SW 58 times and avoid severe sucking. Our automatic program for ECMO showed the satisfactory result as an initial stage. In conclusion, we should he able to control pump flow of ECMO automatically to avoid severe sucking based on motor current.