key: cord-0968703-nz94fxpd authors: Gacitúa, Ignacio; Frías, Alondra; Sanhueza, María E.; Bustamante, Sergio; Cornejo, Rodrigo; Salas, Andrea; Guajardo, Ximena; Torres, Katherine; Figueroa Canales, Enzo; Tobar, Eduardo; Navarro, Rocío; Romero, Carlos title: Extracorporeal CO(2) removal and renal replacement therapy in acute severe respiratory failure in COVID‐19 pneumonia: Case report date: 2021-05-10 journal: Semin Dial DOI: 10.1111/sdi.12980 sha: 01b668d98c52fb412ef248bc4d3b4c156230f815 doc_id: 968703 cord_uid: nz94fxpd The COVID‐19 pandemic significates an enormous number of patients with pneumonia that get complicated with severe acute respiratory distress syndrome (ARDS), some of them with refractory hypercapnia and hypoxemia that need mechanical ventilation (MV). Those patients who are not candidate to extracorporeal membrane oxygenation (ECMO), the extracorporeal removal of CO(2) (ECCO(2)R) can allow ultra protective MV to limit the transpulmonary pressures and avoid ventilatory induced lung injury (VILI). We report a first case of prolonged ECCO(2)R support in 38 year male with severe COVID‐19 pneumonia refractory to conventional support. He was admitted tachypneic and oxygen saturation 71% without supplementary oxygen. The patient's clinical condition worsens with severe respiratory failure, increasing the oxygen requirement and initiating MV in the prone position. After 21 days of protective MV, PaCO(2) rise to 96.8 mmHg, making it necessary to connect to an ECCO(2)R system coupled continuous veno‐venous hemodialysis (CVVHD). However, due to the lack of availability of equipment in the context of the pandemic, a pediatric gas exchange membrane adapted to CVVHD allowed to maintain the removal of CO(2) until completing 27 days, being finally disconnected from the system without complications and with a satisfactory evolution. The COVID-19 pandemic significates an enormous number of patients with pneumonia that get complicated with severe acute respiratory distress syndrome (ARDS), some of them with refractory hypercapnia and hypoxemia that need mechanical ventilation (MV). Those patients who are not candidate to extracorporeal membrane oxygenation (ECMO), the extracorporeal removal of CO 2 (ECCO 2 R) can allow ultra protective MV to limit the transpulmonary pressures and avoid ventilatory induced lung injury (VILI). We report a first case of prolonged ECCO 2 R support in 38 year male with severe COVID-19 pneumonia refractory to conventional support. He was admitted tachypneic and oxygen saturation 71% without supplementary oxygen. The patient's clinical condition worsens with severe respiratory failure, increasing the oxygen requirement and initiating MV in the prone position. After 21 days of protective MV, PaCO 2 rise to 96.8 mmHg, making it necessary to connect to an ECCO 2 R system coupled continuous veno-venous hemodialysis (CVVHD). However, due to the lack of availability of equipment in the context of the pandemic, a pediatric gas exchange membrane adapted to CVVHD allowed to maintain the removal of CO 2 until completing 27 days, being finally disconnected from the system without complications and with a satisfactory evolution. In the 1990 s, Young et al. was the first to report a system that coupled ECCO 2 R to continuous renal replacement therapy (CRRT) through an arterio-venous low flow CO 2 removal device. [8] [9] [10] In 2013, Forster and colleagues showed a similar device that combined CVVHD associated a ECCO 2 R using blood flow less than 500 ml/min in patients with severe ARDS. 11 We present the first case of a patient with severe respiratory failure due to COVID-19 pneumonia in whom CO 2 removal therapy is performed using a pediatric oxygenation membrane coupled to HDVVC. A 38-year-old male with a history of overweight, hypothyroidism and insulin resistance begin with progressive dyspnea and presented to connected to a DIAPACT ® Braun machine (Figure 2 ). This new circuit was kept under optimal anticoagulation and the system operated efficiently for 17 consecutive days, without evidence of pediatric membrane oxygenator failure. After 27 days of ECCO 2 R support, the system was disconnected. During the entire period of ECCO 2 R support there was no evidence of hemorrhagic, hematological, or infectious complications (Figure 3 ). The patient continued his evolution in a stable way, he was able to disconnect from the MV without complications and he was discharged from the hospital to his home. The ECCO 2 R are partial low-flow respiratory support systems that can be implemented with membranes of different surfaces (0.33 to 1.81 m 2 ) and allows extraction of 25% of the CO 2 content in the blood, reducing ventilatory requirements. 4, 13 The CO 2 diffusion capacity is 20 times greater than oxygen, which allows the system to purify CO 2 at low flows of blood (Qb <500 ml/min). The main deter- to 1,000 ml/min. 15 The clinical use of ECCO 2 R systems has been described not only in ARDS but also in chronic obstructive pulmonary disease patients, weaning from MV and as a bridge therapy in lung transplant. 16 The As we noted before, the success of the ECCO 2 R systems depends on vascular access that can achieve blood flow rate up to 500 ml/min and of anticoagulation to maintain aPTT ranges between 70 and 80 seconds. [17] [18] [19] The latter is crucial to maintain membrane patency and avoid membrane fouling. In our clinical case, we had two episodes of circuit clotting despite optimal anticoagulation. The possible explanations of this that there are blood-membrane interaction, activation of the coagulation cascade and a slowdown of the blood in the oxygenator membrane. The patient in our clinical case had a formal contraindication of ECMO because the respiratory failure and consequent respiratory acidosis (PaCO 2 96.8 mmHg and pH 7.21) presented at day 21 of MV, and that was the reason we choose for an ECCO 2 R strategy as a rescue supportive therapy. 20 The use of devices for CO 2 removal as a support strategy in selected critical patients is not new in our environment and has been used for more than a decade. A great number of ECCO 2 R system currently available requires specialized technology and machines specifically designed for this purpose, which can make this technology less accessible. What is distinctive about the present case is that it was the first patient who was treated with CO 2 removal for several weeks, the use of the pediatric oxygenation membrane coupled to HDVVC made it possible to efficiently treat respiratory failure and CO 2 retention, maintaining ultra-protective MV using low Vt for a long period of time. In this case of severe respiratory failure by COVID-19, the innovation of the therapy was able to stabilize gas exchange of the patient and lung function until recovery and withdrawal of invasive MV. This report presents a clinical case of severe hypercapnic respiratory acidosis in which the use of an oxygenation membrane coupled to CRRT allowed after 27 days to reduce the lung injury associated with MV, stabilizing the patient's gas exchange at a low cost. ECCO 2 R associated with HDVVC is a safe and effective therapy in reducing CO 2 , correcting respiratory acidosis and allowing ultraprotective MV. The authors thank Luis Toro for his support, who belongs to the Department of Nephrology, and Diego Espinoza, Resident of Radiology, Hospital Clínico Universidad de Chile, for providing us with images for this manuscript. The authors have no financial conflicts of interest to declare. https://orcid.org/0000-0003-3355-8329 Carlos Romero https://orcid.org/0000-0003-4210-9269 The acute respiratory distress syndrome network. 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