The incremental value of computed tomography of COVID-19 pneumonia in predicting ICU admission.

Triage is crucial for patient's management and estimation of the required intensive care unit (ICU) beds is fundamental for health systems during the COVID-19 pandemic. We assessed whether chest computed tomography (CT) of COVID-19 pneumonia has an incremental role in predicting patient's admission to ICU. We performed volumetric and texture analysis of the areas of the affected lung in CT of 115 outpatients with COVID-19 infection presenting to the emergency room with dyspnea and unresponsive hypoxyemia. Admission blood laboratory including lymphocyte count, serum lactate dehydrogenase, D-dimer and C-reactive protein and the ratio between the arterial partial pressure of oxygen and inspired oxygen were collected. By calculating the areas under the receiver-operating characteristic curves (AUC), we compared the performance of blood laboratory-arterial gas analyses features alone and combined with the CT features in two hybrid models (Hybrid radiological and Hybrid radiomics)for predicting ICU admission. Following a machine learning approach, 63 patients were allocated to the training and 52 to the validation set. Twenty-nine (25%) of patients were admitted to ICU. The Hybrid radiological model comprising the lung %consolidation performed significantly (p = 0.04) better in predicting ICU admission in the validation (AUC = 0.82; 95% confidence interval 0.73-0.97) set than the blood laboratory-arterial gas analyses features alone (AUC = 0.71; 95% confidence interval 0.56-0.86). A risk calculator for ICU admission was derived and is available at: https://github.com/cgplab/covidapp . The volume of the consolidated lung in CT of patients with COVID-19 pneumonia has a mild but significant incremental value in predicting ICU admission.

Sustained oxygenation improvement after first prone positioning is associated with liberation from mechanical ventilation and mortality in critically ill COVID-19 patients: a cohort study.

BACKGROUND: Prone positioning (PP) has been used to improve oxygenation in patients affected by the SARS-CoV-2 disease (COVID-19). Several mechanisms, including lung recruitment and better lung ventilation/perfusion matching, make a relevant rational for using PP. However, not all patients maintain the oxygenation improvement after returning to supine position. Nevertheless, no evidence exists that a sustained oxygenation response after PP is associated to outcome in mechanically ventilated COVID-19 patients. We analyzed data from 191 patients affected by COVID-19-related acute respiratory distress syndrome undergoing PP for clinical reasons. Clinical history, severity scores and respiratory mechanics were analyzed. Patients were classified as responders (≥ median PaO2/FiO2 variation) or non-responders (< median PaO2/FiO2 variation) based on the PaO2/FiO2 percentage change between pre-proning and 1 to 3 h after re-supination in the first prone positioning session. Differences among the groups in physiological variables, complication rates and outcome were evaluated. A competing risk regression analysis was conducted to evaluate if PaO2/FiO2 response after the first pronation cycle was associated to liberation from mechanical ventilation. RESULTS: The median PaO2/FiO2 variation after the first PP cycle was 49 [19-100%] and no differences were found in demographics, comorbidities, ventilatory treatment and PaO2/FiO2 before PP between responders (96/191) and non-responders (95/191). Despite no differences in ICU length of stay, non-responders had a higher rate of tracheostomy (70.5% vs 47.9, P = 0.008) and mortality (53.7% vs 33.3%, P = 0.006), as compared to responders. Moreover, oxygenation response after the first PP was independently associated to liberation from mechanical ventilation at 28 days and was increasingly higher being higher the oxygenation response to PP. CONCLUSIONS: Sustained oxygenation improvement after first PP session is independently associated to improved survival and reduced duration of mechanical ventilation in critically ill COVID-19 patients.

COVID-19 and VILI: developing a mobile app for measurement of mechanical power at a glance.

The COVID-19 pandemic has increased the need for a bedside tool for lung mechanics assessment and ventilator-induced lung injury (VILI) monitoring. Mechanical power is a unifying concept including all the components which can possibly cause VILI (volume, pressures, flow, respiratory rate), but the complexity of its mathematical computation makes it not so feasible in routine practice and limits its clinical use. In this letter, we describe the development of a mobile application that allows to simply measure power associated with mechanical ventilation, identifying each component (respiratory rate, resistance, driving pressure, PEEP volume) as well. The major advantage, according to the authors who developed this mathematical description of mechanical power, is that it enables the quantification of the relative contribution of its different components (tidal volume, driving pressure, respiratory rate, resistance). Considering the potential role of medical apps to improve work efficiency, we developed an open source Progressive Web Application (PWA), named "PowerApp" (freely available at https://mechpower.goodbarber.app ), in order to easily obtain a bedside measurement of mechanical power and its components. It also allows to predict how the modification of ventilatory settings or physiological conditions would affect power and each relative component. The "PowerApp" allows to measure mechanical power at a glance during mechanical ventilation, without complex mathematical computation, and making mechanical power equation useful and feasible for everyday clinical practice.

D-dimer as an indicator of prognosis in SARS-CoV-2 infection: a systematic review.

BACKGROUND: Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) stimulates pro-thrombotic changes. This, combined with its tropism for endothelium and lung structures, may explain its association with thrombotic events, reduction of pulmonary gas exchange, acute respiratory distress syndrome (ARDS) and a composite end-point (intensive care unit, invasive ventilation, death). This study aims to highlight the correlation between elevated D-dimer (an indirect thrombosis marker) and the increased rate of poor prognosis-associated conditions, and to introduce D-dimer-labelled anticoagulant administration as a potentially useful tool to prevent complications and positively influence coronavirus disease 2019 (COVID-19) course. METHODS: An online database search (PubMed, Google Scholar, Scopus, Web of Science and Cochrane) was performed between 13 March and 10 April 2020. The most relevant keywords were "D-dimer", "SARS-CoV-2", "COVID-19", "thrombosis" and "ARDS". Selection was independently conducted by three reviewers. References and previews of accepted articles were evaluated. Data inclusion/extraction inaccuracy was limited by the work of three reviewers. Selection bias reduction was addressed by thoughtfully designing the search protocol. Quality assessment was performed with the Newcastle-Ottawa Scale. The systematic review protocol was not registered because we anticipated the very limited available evidence on the topic and due to the urgency of the study. RESULTS: 16 studies were evaluated. Good-quality criteria were reached in 13 out of 16 studies. D-dimer was increased and significantly higher in COVID-19 patients compared with healthy controls, in COVID-19 patients with severe disease or a composite end-point compared with non-severe disease, in ARDS compared with non-ARDS patients and in deceased ARDS patients compared with ARDS patients who survived (all p<0.001). COVID-19 patients treated with anticoagulants demonstrated lower mortality compared with those not treated (p=0.017). CONCLUSIONS: Correlations exist between COVID-19 infection, severe elevation of D-dimer levels, and increase in the rate of complications and composite end-point. The appropriateness of early and continuous D-dimer monitoring and labelled anticoagulation as management tools for COVID-19 disease deserves accurate investigation, to prevent complications and reduce interventions.