Introduction:

The SARS-CoV-2 pandemic has inspired interest in the immune response to the virus, especially in severe patients with acute respiratory distress syndrome (ARDS). The study describes the behaviour of the immune response, immune suppression, and their results in patients under mechanical ventilation (MV).

Material and methods:

Prospective cohort. From March 23rd to December 31st, 2020, we recollected basal information, MV parameters, blood gas analysis and laboratory studies of all the patients over 18 years who received MV secondary to COVID-19. We registered 15 continuous days of MV. We divided the groups in patients alive at day 60 and deaths.

Results:

We included 218 patients with a mortality of 23%. In day 1 of MV, the patients didn’t have any differences in cell counts or acute phase reactants, except for D Dimer (705-1,711) vs 1,328 (940-2,340) ng/dL p = 0.035. In mixed effects linear regressions, we found statistically significant chronological differences in C reactive protein (CPR) and leucocyte count, concordant with the elevation of the driving pressure (DP). In the Cox regression we found no association with tocilizumab and corticosteroids with mortality on day 1 of MV. Patients who died received higher doses of corticosteroids throughout the 15 days of MV, with doses equivalent to prednisone over 150 mg/day are associated with mortality.

Conclusions:

There is a similar chronological behaviour in the elevation of acute phase reactants and the elevation con DP with no elevation of Vt, which can be explained by the drop of total PEEP and Cstat. There was no association with the use of tocilizumab and mortality, and a dose of 100-150 mg/día of equivalent of prednisone was associated with better results.

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