Application of extracorporeal carbon dioxide removal combined with continuous blood purification therapy in ARDS with hypercapnia in patients with critical COVID-19.

INTRODUCTION: Coronavirus disease-19 (COVID-19) is a new type of epidemic pneumonia caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The population is generally susceptible to COVID-19, which mainly causes lung injury. Some cases may develop severe acute respiratory distress syndrome (ARDS). Currently, ARDS treatment is mainly mechanical ventilation, but mechanical ventilation often causes ventilator-induced lung injury (VILI) accompanied by hypercapnia in 14% of patients. Extracorporeal carbon dioxide removal (ECCO2R) can remove carbon dioxide from the blood of patients with ARDS, correct the respiratory acidosis, reduce the tidal volume and airway pressure, and reduce the incidence of VILI.

CASE REPORT: Two patients with critical COVID-19 combined with multiple organ failure undertook mechanical ventilation and suffered from hypercapnia. ECCO2R, combined with continuous renal replacement therapy (CRRT), was conducted concomitantly. In both cases (No. 1 and 2), the tidal volume and positive end-expiratory pressure (PEEP) were down-regulated before the treatment and at 1.5 hours, one day, three days, five days, eight days, and ten days after the treatment, together with a noticeable decrease in PCO2 and clear increase in PO2, while FiO2 decreased to approximately 40%. In case No 2, compared with the condition before treatment, the PCO2 decreased significantly with down-regulation in the tidal volume and PEEP and improvement in the pulmonary edema and ARDS after the treatment.

CONCLUSION: ECCO2R combined with continuous blood purification therapy in patients with COVID-19 who are criti-cally ill and have ARDS and hypercapnia might gain both time and opportunity in the treatment, down-regulate the ventilator parameters, reduce the incidence of VILI and achieve favorable therapeutic outcomes.