The Effect of Simultaneous Renal Replacement Therapy on Extracorporeal Membrane Oxygenation Support for Cardiogenic Shock Patients

Background:

Extracorporeal membrane oxygenation (ECMO) is a temporary mechanical circulatory support device for cardiogenic shock (CS) patients. Patients with fluid overload (FO) and sever metabolic disorder in the early phase of ECMO support exhibit higher hospital mortality. Simultaneous renal replacement therapy (RRT) is routinely used to facilitate more rapid metabolic or uremic control and more effective prevention and management of fluid overload when ECMO is commenced in some ECMO centers registered in the Extracorporeal Life Support Organization (ELSO). However, high-quality evidence to support the strategy of simultaneous RRT during ECMO support is currently lacking. The investigators aim to perform a single center, randomized, controlled trial to evaluate the impact of simultaneous RRT on outcomes during ECMO support for CS patients.

Hypotheses:

The investigators hypothesize that simultaneous RRT with ECMO will improve survival, reduce morbidity, and shorten duration on ECMO support, duration on invasive ventilation, total days of ICU stay and hospitalization, and time to recovery from electrolyte disturbance.

Design:

Prospective, single-center, randomized, open-label trial comparing simultaneous RRT and standard care strategies in terms of overall survival.

CS patients who are likely to receive ECMO support will be enrolled and randomized with a 1:1 allocation to a simultaneous RRT arm vs. standard care arm.

1. Simultaneous RRT arm: The continuous renal replacement therapy (CRRT) machine is primed and connected to the patient by a "machine in-line" CRRT access after randomization. The drainage tube of the CRRT machine is connected to the ECMO circuit where is after the membrane lung, and the return tube before the membrane lung. The simultaneous RRT begins after ECMO is commenced and finishes when a patient has been weaned from ECMO. If a patient has AKI (The definition is described in outcomes.) after ECMO weaning and fulfills any of the criteria of the following conventional indications, conventional-indication RRT should be delivered with independent CRRT access with a central venous catheter: (1) Serum potassium≥6.0 mmol/L, (2) Serum bicarbonate≤10 mmol/L, or (3) urine output < 0.5 ml/kg/h for 24 hours after ECMO weaning.
2. Standard care arm: Only when a patient demonstrates AKI and fulfills any one of the criteria of the conventional indication mentioned above during ECMO support or after ECMO weaning, conventional-indication RRT should be delivered. The "machine in-line" CRRT access or independent CRRT access is separately used when RRT is delivered during ECMO support or after ECMO weaning.

Primary outcome:

All-cause 30-day mortality after ECMO is commenced.

Secondary outcomes:

Morbidity (acute kidney injury, infection), duration on ECMO support, duration on invasive ventilation, total days of ICU stay and hospitalization, and time to recovery from electrolyte disturbance.

Number of subjects required:

The baseline hospital mortality (66%) of CS patients with ECMO support was obtained from the investigators' previous study. Based on their literature research, early initiation of RRT could reduce the mortality by 18%. Assuming all-cause 30-day mortalities in the control and intervention groups of 66% and 48%, respectively, with a two-sided significance of 0.05 and a power of 0.8, a total of 262 patients (131 for each arm) will be required, including an estimated dropout rate of 10%.