A retrospective comparison between influenza and COVID-19-associated ARDS in a Croatian tertiary care center

Since the beginning of the Corona virus disease 2019 (COVID-19) pandemic the new Severe acute respiratory syndrome coronoavirus 2 (SARS-CoV‑2) virus has been repeatedly compared to the influenza virus; however, the comparison of invasively mechanically ventilated patients with acute respiratory distress syndrome (ARDS) caused by these viruses is very scarce. The purpose of this study was to compare clinical course and laboratory parameters between the most severely ill flu and COVID 19 patients treated with invasive mechanical ventilation (IMV).

The study was conducted at the intensive care unit (ICU) of the tertiary care hospital in Zagreb, Croatia in the period between November 2018 and July 2020. Investigation included 72 adult patients requiring IMV due to influenza or SARS-CoV‑2 virus infection and 42 patients had influenza and 30 had SARS-CoV‑2 virus infection and the comparison between two etiological groups was conducted.

Invasively mechanically ventilated patients with COVID 19 and influenza differ in certain aspects. COVID 19 patients are older, male, have lower C-reactive protein (CRP) levels and have less need for extracorporeal membrane oxygenation (ECMO) support. In other measured variables, including mortality, the difference between influenza or SARS-CoV‑2 etiology was not significant.

High mortality of IMV patients with influenza and COVID 19 with 55% and 63%, respectively, challenges and urges medical and especially ICU community to expand our quest for further treatments, especially since ECMO use that is scarcely required in COVID 19 patients probably has limited impact in reducing mortality in COVID 19 patients.