Patients receiving extracorporeal membrane oxygenation (ECMO) often suffer from acute kidney injury (AKI), requiring continuous renal replacement therapy (CRRT). In our clinical practice, we connected the inlet line of a CRRT machine to the postoxygenator Luer port and the outlet line to the inlet Luer port of the oxygenator. In this case series, we analyzed the interaction between the two machines. Between December 31, 2017, and December 31, 2019, we enrolled 15 patients from the ICU of the San Matteo Hospital, Pavia, Italy. All of them suffered from severe acute respiratory distress syndrome and AKI stage 3. We analyzed 570 hours of CRRT combined with venovenous ECMO and collected 261,751 CRRT data. No discontinuation of CRRT occurred before 48 hours. Most of the alarms occurred within 24 hours of the connection: 22/10,831 (0.2%) showed an outranged inlet pressure, 11/10831 (0.11%) showed an outranged transmembrane pressure, 14/10,831 (0.13%) showed an outranged inlet pressure, and 138/10,831 (1.27%) an outranged effluent pressure.

The rate per minute set for the ECMO circuit was correlated with the inlet (β = 5.38; CI, 95% 1.42–9.35; p = 0.008), transmembrane (β = 4.6; CI, 95% 1.97–7.24; p = 0.001), effluent (β = 3.02; CI, 95% 1.15–4.90; p = 0.002), and outlet pressures (β = 597; CI, 95% 2.31–9.63; p = 0.001) of the CRRT circuit. We reported that our configuration could be safe and effective, however well-designed studies would be beneficial for determining the potential risks and benefits.