Directed Hypercapnia for Weaning From ECMO to Mechanical Ventilation—Progress or Just a Process?

Abstract

In this issue of The Annals of Thoracic Surgery, Kluis and colleagues1Kluis A. Shih E. Squiers J.J. et al.Directed hypercapnia as a strategy to wean extracorporeal membrane oxygenation in COVID-19 pneumonia.Ann Thorac Surg. 2022; 114: e307-e309Abstract Full Text Full Text PDF Scopus (1) Google Scholar report a single-institution experience with 5 cases of severe COVID-19 acute respiratory distress syndrome (ARDS) with hypercarbic respiratory failure using directed hypercapnia as a strategy to wean patients from venovenous extracorporeal membrane oxygenation (ECMO). The authors instituted a directed hypercapnia approach in combination with metabolically compensated respiratory acidosis to terminate long-term ECMO support and to reduce associated morbidity and mortality. Five patients were successfully weaned off ECMO. One patient with preexisting kidney disease requiring renal replacement therapy ultimately died of refractory acidosis and sepsis. ECMO duration ranged from 56 to 167 days, highlighting the extended duration of support. More than 13,000 cases of COVID-19 requiring ECMO have been reported to the Extracorporeal Life Support Organization registry with a 47% in-hospital mortality.2Extracorporeal Life Support OrganizationELSO live registry dashboard of ECMO patient data.https://www.elso.org/Registry/ELSOLiveRegistryDashboard.aspxDate accessed: March 20, 2022Google Scholar Early use of ECMO for COVID-19 resulted in poor outcomes, with many clinicians discouraging this application.3Henry B.M. Lippi G. Poor survival with extracorporeal membrane oxygenation in acute respiratory distress syndrome (ARDS) due to coronavirus disease 2019 (COVID-19): pooled analysis of early reports.J Crit Care. 2020; 58: 27-28Crossref PubMed Scopus (144) Google Scholar As the pandemic progressed, ECMO use increased rapidly, and more recent data suggest similar outcomes to non-COVID ARDS.4Barbaro R.P. MacLaren G. Boonstra P.S. et al.Extracorporeal membrane oxygenation support in COVID-19: an international cohort study of the Extracorporeal Life Support Organization registry.Lancet. 2020; 396: 1071-1078Abstract Full Text Full Text PDF PubMed Scopus (420) Google Scholar Much of the management of ECMO and mechanical ventilation has been extrapolated from non-COVID ARDS populations. Whereas most centers use lung-protective ventilation, there are no standard guidelines for ventilator management in this setting. Institutional demands and experiences often dictate the pathway of care. The authors report an ECMO weaning protocol that successfully liberated patients from this high-risk, resource-intensive therapy, allowing discharge from a tertiary center to long-term acute rehabilitation facilities. At the individual patient level, this may translate into decreases in the morbidity and mortality associated with prolonged ECMO. At the health system level, the economic and resource allocation benefits associated with freeing up intensive care beds, staff, and resources could be immense. This protocol could be particularly valuable during high infectivity periods when the health system is significantly strained. Certain considerations temper enthusiasm for widespread adoption of this protocol. Individualized care is essential, and recovery is the primary aim. As reported, all survivors remain on assist-control ventilation, and long-term outcomes, including prospects for eventual ventilator liberation, are unknown. Patients may have been better served with sedative reduction, extubation, and ambulation on ECMO. In addition, proponents of directed hypercapnia must ensure that protocols do not restrict evaluation for lung transplantation. Outcomes from ECMO bridging to transplantation have improved because of better patient selection and protocolized management approaches. As highlighted in a recent US nationwide analysis published in the New England Journal of Medicine, lung transplantation is an important option for refractory COVID-19 ARDS or post-COVID fibrosis, with promising early outcomes including 95% 3-month survival in more than 200 recipients.5Roach A. Chikwe J. Catarino P. et al.Lung transplantation for Covid-19–related respiratory failure in the United States.N Engl J Med. 2022; 386: 1187-1188Crossref PubMed Scopus (24) Google Scholar Notwithstanding, there will likely be a role for directed hypercapnia in this population, which will be further delineated as more research is performed. Directed Hypercapnia as a Strategy to Wean Extracorporeal Membrane Oxygenation in COVID-19 PneumoniaThe Annals of Thoracic SurgeryVol. 114Issue 5PreviewCoronavirus disease 2019 pneumonia with respiratory failure refractory to maximum medical therapy has been successfully managed with venovenous extracorporeal membrane oxygenation. This report describes a process of using directed hypercapnia in 5 patients to wean them from prolonged extracorporeal support secondary to refractory hypercarbic respiratory failure. Full-Text PDF