Natural history, trajectory, and management of mechanically ventilated COVID-19 patients in the United Kingdom

Abstract

Background. To date the description of mechanically ventilated patients with Coronavirus Disease 2019 (COVID-19) has focussed on admission characteristics with no consideration of the dynamic course of the disease. Here, we present a data-driven analysis of granular, daily data from a representative proportion of patients undergoing invasive mechanical ventilation (IMV) within the United Kingdom (UK) to evaluate the complete natural history of COVID-19. Methods. We included adult patients undergoing IMV within 48 hours of ICU admission with complete clinical data until intensive care unit (ICU) death or discharge. We examined factors and trajectories that determined disease progression and responsiveness to interventions used in acute respiratory distress syndrome (ARDS). Our data visualisation tool is available as a web-based widget (https://www.CovidUK.ICU). Findings. Data for 633 adults with COVID-19 who were mechanically ventilated between 01 March 2020 and 31 August 2020 were analysed. Mortality, intensity of mechanical ventilation and severity of organ injury increased with severity of hypoxaemia. Median PaO2/FiO2 in non-survivors on the day of death was 12.3(8.9-18.4) kPa suggesting severe refractory hypoxaemia as a major contributor to mortality. Non-resolution of hypoxaemia over the first week of IMV was associated with higher ICU mortality (60.4% versus 17.6%; P<0.001). The reported ideal body weight overestimated our calculated ideal body weight derived from reported height, with three-quarters of all reported tidal volume values were above 6mL/kg of ideal body weight. Overall, 76% of patients with moderate hypoxaemia and 46% with severe did not undergo prone position at any stage of admission. Furthermore, only 45% showed a persistent oxygenation response on prone position. Non-responders to prone position show higher lactate, D-Dimers, troponin, cardiovascular component of the sequential organ failure assessment (SOFA) score, and higher ICU mortality (69.5% versus 31.1%; P<0.001). There was no difference in number of prone sessions between survivors and non-survivors, however, patients who died without receiving prone position had a greater number of missed opportunities for prone intervention (7(3-15.5) versus 2(0-6); P<0.001). Interpretation. A sizeable proportion of patients with progressive worsening of hypoxaemia had no application of and were refractory to evidence based ARDS strategies and showed a higher mortality. Strategies for early recognition and management of COVID-19 patients refractory to conventional management strategies will be critical to improving future outcomes.

Mechanisms of oxygenation responses to proning and recruitment in COVID-19 pneumonia

“…As the prevalence of these changes are coherent with a progressive evolution of the lung pathology towards organizing pneumonia and "fibrosis-like" status [29][30][31][32] it is tempting to speculate that time had a key-role on the evolution of COVID-19 pneumonia. A decreased response with time to prone position and recruitment manoeuvers, however, has been previously described in COVID-19 and in non-COVID-19 ARDS [31,33,34].…”

Ventilator-Associated Lung Injury

“…A more contentious issue is the duration of which each prone intervention is applied but also when a prone period is terminated. The coronavirus pandemic has seen a surge in the need for optimal management of the ventilator through more sophisticated data science approaches to understand these gaps such that they can be improved through better bedside measurements and algorithms ( Patel et al, 2021 ). Hence, there is significant rationale for the development of point-of-care clinical decision support systems which help personalize ventilatory strategy according to the current physiology ( Rees et al, 2006a ; Nieman et al, 2017 ; Karbing et al, 2018 , Karbing et al, 2020 ).…”

Pathophysiology of coronavirus-19 disease acute lung injury

“…The majority of patients admitted to critical care have a PaO 2 /FiO 2 ratio <26.7 kPa (200 mmHg) consistent with moderate or severe ARDS [ 2 , 6 ]. Despite the low PaO 2 /FiO 2 ratio, most patients have preserved lung volumes at presentation, and the lung radiology shows bilateral multifocal ground-glass appearance mainly with peripheral distribution and minimal parenchymal consolidation [ 7 ▪ ].…”