Aspects of ventilation management and clinical outcomes in COVID-19 patients

Coronavirus disease 2019 (COVID–19) can cause acute respiratory failure requiring invasive ventilation. At the beginning of the pandemic, no evidence existed on how to ventilate this specific group of patients. The general aim of this thesis was to investigate how COVID–19 patients were invasively ventilated, more specifically during the first wave of the pandemic in the Netherlands, and examine associations with outcome. The following five hypotheses were tested: 1) COVID–19 patients were ventilated in a comparable way to patients with acute respiratory distress syndrome (ARDS) of another origin; 2) ventilation management was associated with outcome in invasively ventilated COVID–19 patients; 3) a lower positive end expiratory pressure (PEEP) strategy was inferior to a higher PEEP strategy; 4) hypercapnia and hyperoxemia were prevalent and associated with outcome, and 5) timing of tracheostomy was associated with outcome. The main findings of this thesis were that lung–protective ventilation was applied very well in COVID–19 patients needing invasive ventilation and that use of a lower tidal volume was associated with lower mortality. Furthermore, present uncertainties regarding mechanical ventilation in patients with ARDS of another origin, such as appropriate use of PEEP, meaningful ranges for arterial blood gas analyses results, and optimal timing of tracheostomy, also remain unresolved in invasively ventilated COVID–19 patients.