RESUMO
OBJECTIVE: To assess the feasibility of delivering extracorporeal cardiopulmonary resuscitation (ECPR) in refractory out-of-hospital cardiac arrests (OHCA) by low volume extracorporeal membrane oxygenation (ECMO) centers and to explore pre-ECPR predictors of survival. METHODS: Between 2016 and 2020, we studied 21 ECPR patients admitted in 2 tertiary ECMO centers in Liège, Belgium. Our ECPR protocol was based on 6 prehospital criteria (no flow < 3 minutes, low flow < 60 minutes, initial shockable rhythm, end-tidal CO2 > 15 mmHg, age < 65 years, and absence of comorbidities). A dedicated training, prehospital checklist and call number for 24/7 ECMO team assistance were implemented. Hemodynamics and blood gases on admission also were assessed. RESULTS: Twenty-one (28%) out of 75 refractory OHCA patients referred were treated by ECPR, with a hospital survival rate of 43% (n = 9/21), comparable to ECPR results from the international extracorporeal life support organization registry. Transient return of spontaneous circulation before ECPR (89% in survivors vs 17% in non-survivors, P = 0.002) and higher initial serum bicarbonate (med [P25-P75] 14.0 [10.6-15.2] vs 7.5 [3.7-10.5] mmol/L, P = 0.019) or lower initial base deficit (14.9 [11.9-18.2] vs 21.6 [17.9-28.9] mmol/L, P = 0.039) were associated with a more favorable outcome. CONCLUSION: In low volume ECMO centers, the implementation of a specific ECPR protocol for refractory OHCA patients is feasible and provides potential clinical benefit. Highly selective inclusion criteria seem essential to select candidates for ECPR. Initial serum bicarbonate and base deficit integrating cumulative cell failure may be relevant pre-ECMO prognostic factors and require larger-scale evaluation.
RESUMO
In the context of the coronavirus disease 2019 pandemic, myocardial injury is a relatively frequent finding. Progression to cardiogenic shock has been rarely described, especially in healthy young patients. The underlying mechanisms are to date controversial. A previously healthy 18-year-old female teenager affected by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) developed fulminant cardiogenic shock requiring a prompt extracorporeal membrane oxygenation support. Cardiac involvement was predominant compared with the pulmonary one. Myocardial biopsies were performed; and in order to clarify the pathophysiology of the acute heart failure, optical and transmission electron microscopy study was realized. Two additional immunohistology techniques were developed in order to (i) detect a SARS-CoV-2 recombinant fusion nucleoprotein by using a specific antibody and (ii) study fractalkine expression induced by activated endothelium because this molecule is well known to be elevated in patients with severe cytokine release syndrome. SARS-CoV-2 genome was not detected in the myocardium. Even if the clinical presentation, laboratory markers, and cardiac imaging techniques strongly suggested fulminant myocarditis, histology and immunohistology were not fully consistent with this diagnosis according to the Dallas criteria. Although rare suspected coronavirus particles were found by transmission electron microscopy in the cardiac endothelium, neither significant immunoreactivity for the viral nucleocapsid protein nor image suggestive of endotheliitis was detected. Intense endothelial immunoreactivity pattern for fractalkine expression was observed. From a clinical point of view, the left ventricular systolic function gradually improved, and the patient survived after a long stay in the intensive care unit. Our observations suggest that a massive cytokine storm induced by SARS-CoV-2 infection was the main cause of the cardiogenic shock, making a direct viral injury pathway very unlikely.