Creating a Controlled Arterio-Venous Shunt by Reversing the Extracorporeal Membrane Oxygenation Blood Flow: A Strategy for Weaning Patients Off Veno-Arterial Extracorporeal Membrane Oxygenation.

OBJECTIVES: To assess whether reversing the veno-arterial extracorporeal membrane oxygenation blood flow (thereby creating a controlled arterio-venous shunt) can be used to wean children off extracorporeal membrane oxygenation. The standard practice for weaning patients off VA extracorporeal membrane oxygenation is to gradually reduce the blood flows delivered through the extracorporeal membrane oxygenation pump to a minimum level followed by either insertion of an "arterio-venous bridge" and clamping of the blood flow to the patient or direct decannulation. "Pump controlled retrograde flow trial off" is a technique where the revolutions in the centrifugal pump are reduced to the point where the patient will drive the blood retrograde through the extracorporeal membrane oxygenation circuit, effectively turning the circuit into a controlled arterio-venous shunt. The revolutions per minute control the amount of shunt flow. This eliminates any cardiorespiratory support the extracorporeal membrane oxygenation circuit may provide to the patient.

DESIGN: Feasibility study.

SETTING: Pediatric intensive care.

PATIENTS: Extracorporeal membrane oxygenation-dependent pediatric patients, who were ready for weaning, and possible separation from extracorporeal membrane oxygenation entered the trial.

INTERVENTION: Pump controlled retrograde flow trial off.

MEASUREMENT AND MAIN RESULTS: During 2016, pump controlled retrograde flow trial off was used in 17 patients, for a total of 23 episodes. One episode was unsuccessful in a patient with a body weight of 2.2 kg, where cardiac output was insufficient to provide blood flow to both body and extracorporeal membrane oxygenation circuit, though from 2.8 kg body weight upward, the technique was tolerated. The duration of pump controlled retrograde flow trial off was 15 minutes to 2.5 hours. Five cases led to a continuation of the extracorporeal membrane oxygenation run, as they were not ready to be decannulated. Fifteen patients were decannulated after the pump controlled retrograde flow trial off. No patient needed to be recommenced on extracorporeal membrane oxygenation after decannulation.

CONCLUSIONS: Pump controlled retrograde flow trial off is an easy to use and easily reversible technique to assess patient readiness for separation from extracorporeal membrane oxygenation. Given pump controlled retrograde flow trial off can easily be stopped and-in our experience-is not associated with complications, it lowers the threshold to attempt coming off extracorporeal membrane oxygenation and facilitates accurate assessment of whether a patient will need further ongoing extracorporeal membrane oxygenation support.