Low-flow ECCO 2 R conjoined with renal replacement therapy platform to manage pulmonary vascular dysfunction with refractory hypercapnia in ARDS.

BACKGROUND: Hypercapnia worsens lung vascular dysfunction during acute respiratory distress syndrome (ARDS). We tested whether an extracorporeal carbon dioxide removal (ECCO2 R) device based on a renal replacement therapy platform (Prismalung®) may reduce PaCO2 and alleviate lung vascular dysfunction in ARDS patients with refractory hypercapnia.

METHODS: We planned to prospectively include 20 patients with moderate-to-severe ARDS, pulmonary vascular dysfunction on echocardiography, and PaCO2 ≥ 48 mmHg despite instrumental dead space reduction and the increase in respiratory rate. Hemodynamics, echocardiography, respiratory mechanics, and arterial blood gases were recorded at 2 (H2), 6 (H6) and 24 (H24) hours as ECCO2 R treatment was continued for at least 24 h.

RESULTS: Only eight patients were included, and the study was stopped due to worldwide shortage of ECCO2 R membranes and the pandemic. Only one patient fulfilled the primary endpoint criterion (decrease in PaCO2 of more than 20 %) at H2, but this objective was achieved in half of patients (n = 4) at H6. The percentage of patients with a PaCO2 value < 48 mmHg increased with time, from 0/8 (0 %) at H0, to 3/8 (37.5 %) at H2 and 4/8 (50 %) at H6 (p = 0.04). There was no major change in hemodynamic and echocardiographic variables with ECCO2 R, except for a significant decrease in heart rate. ECCO2 R was prematurely discontinued before H24 in five (62.5 %) patients, due to membrane clotting in all cases.

CONCLUSIONS: This pilot study testing showed a narrow efficacy and high rate of membrane thrombosis with the first version of the system. Improved versions should be tested in future trials.

TRIAL REGISTRATION: Registered at clinicaltrials.gov, identifier: NCT03303807, Registered: October 6, 2017, https://clinicaltrials.gov/ct2/show/NCT03303807.