COVID-19-Related severe heterogeneous acute respiratory distress syndrome: A therapeutic challenge

Background: A heterogeneous pattern was detected in COVID-19 severe acute respiratory distress syndrome (ARDS) patients. The aim of this study was to define special features and individualized treatment modalities for this fatal infectious disease. Methods: Thirty-six patients diagnosed as COVID-19 severe ARDS were chosen. Lung mechanics (compliance), the extravascular lung water index (EVLWI) and pulmonary vascular permeability index (PVPI), and serum concentrations of immunology markers (interleukin [IL]-1 beta, IL-6, IL-8, ferritin, and C-reactive protein) were measured. Accordingly, individualized treatment consisting of Actemra, hemoperfusion (HP), continuous renal replacement therapy (CRRT), and extracorporeal membrane oxygenation (ECMO) was implemented for each patient. Results: Patients were categorized according to the lung compliance: 18 in "L type" with compliance >40 cc/cmH2O and 18 in "H type" with compliance <= 40 cc/cmH2O. In 16 patients, standard mechanical ventilation management and antiviral therapy were unsuccessful; therefore, hemodynamic and immunity responses were evaluated. Results of transpulmonary thermodilution in L-type patients surprisingly showed EVLWI = 8.8 +/- 1.3 (6.9-9.7) and PVPI = 2.4 +/- 0.1 (2.2-2.6). In the H-type patients, five cases showed EVLWI = 8.7 +/- 0.8 (7.5-9.8) and PVPI = 2.6 +/- 0.3 (2.1-2.8) which were subclassified as "Ha type" and five cases with EVLWI = 17.5 +/- 1.9 (15.7-20.6) and PVPI = 3.9 +/- 0.4 (3.5-4.5) were named "Hb type". By measuring immunologic markers, these two groups were subdivided into high and low marker groups. Individualized treatment resulted in 2 survivals with Actemra, 1 with HP, 2 with HP + CRRT, and 1 with ECMO. Conclusion: According to the heterogeneity of COVID-19 severe ARDS presentation, which is due to various immunologic and hemodynamic responses, a systematic approach is an important and relatively successful strategy in choosing the appropriate treatment modality.