Extracorporeal Carbon Dioxide Removal Using a Renal Replacement Therapy Platform to Enhance Lung-Protective Ventilation in Hypercapnic Patients With Coronavirus Disease 2019-Associated Acute Respiratory Distress Syndrome

Abstract

Coronavirus disease 2019 (COVID-19)-associated acute respiratory distress syndrome (ARDS) is associated with high mortality. Lung-protective ventilation is the current standard of care in patients with ARDS, but it might lead to hypercapnia, which is independently associated with worse outcomes. Extracorporeal carbon dioxide removal (ECCO2R) has been proposed as an adjuvant therapy to avoid progression of clinical severity and limit further ventilator-induced lung injury, but its use in COVID-19 has not been described yet. Acute kidney injury requiring renal replacement therapy (RRT) is common among critically ill COVID-19 patients. In centers with available dialysis, low-flow ECCO2R (<500 mL/min) using RRT platforms could be carried out by dialysis specialists and might be an option to efficiently allocate resources during the COVID-19 pandemic for patients with hypercapnia as the main indication. Here, we report the feasibility, safety, and efficacy of ECCO2R using an RRT platform to provide either standalone ECCO2R or ECCO2R combined with RRT in four hypercapnic patients with moderate ARDS. A randomized clinical trial is required to assess the overall benefit and harm. Clinical Trial Registration: ClinicalTrials.gov. Unique identifier: NCT04351906.

Keywords: SARS-CoV-2; continuous renal replacement therapy; extracorporeal organ support; respiratory acidosis; respiratory dialysis.

Copyright © 2020 Husain-Syed, Birk, Wilhelm, Ronco, Ranieri, Karle, Kuhnert, Tello, Hecker, Morty, Herold, Kehl, Walmrath, Seeger and Vadász.

Figures

Figure 1

Schematic representation of the ECCO2R circuit either as standalone therapy (A) or in-line after the hemofilter for combined ECCO2R and RRT (B). ECCO2R in conjunction with RRT may be performed with regional citrate anticoagulation (1) or systemic heparinization (2). Ca, calcium chloride solution; Ci, trisodium citrate solution; Pump 1, blood line; Pump 2, effluent dialysate line; Pump 3, dialysate line; P1, in-flow pressure sensor; P2, pre-filter pressure sensor; P3, out-flow pressure sensor; P4, effluent dialysate pressure sensor; RRT, renal replacement therapy.

Figure 2

ECCO2R rapidly normalizes arterial hypercapnia in patients with ARDS secondary to COVID-19, allowing de-escalation of ventilatory parameters. (A) To enhance carbon dioxide removal, ECCO2R was applied with a constant blood flow of 400 mL/min (patients 1–3) or 200 mL/min (patient 4; combined with CRRT) administering a sweep gas flow at a gas/blood flow ratio of 15:1 (6 or 3.5 L/min, respectively). Time course of blood gases and ventilator parameters is depicted. (B) Pre- to post-ECCO2R changes in PCO2, bicarbonate, and base excess levels in all four patients that simultaneously points as in (A) are shown upon ECCO2R therapy. ARDS, acute respiratory distress syndrome; BE, base excess; COVID-19, coronavirus disease 2019; CRRT, continuous renal replacement therapy; ECCO2R, extracorporeal carbon dioxide removal; FiO2, fraction of inspired oxygen; HCO3, bicarbonate; PaCO2, arterial partial pressure of carbon dioxide; PBW, predicted body weight; PCO2, venous partial pressure of carbon dioxide; PaO2, arterial partial pressure of oxygen; RR, respiratory rate; VE, minute volume; VT, tidal volume.