378 ORIGINAL ARTICLE Clinical characteristics, comorbidities and mortality in critically ill mechanically ventilated patients with Covid-19: a retrospective observational study Adisa Šabanović Adilović 1 , Nermina Rizvanović 1 , Mirza Kovačević 1 , Harun Adilović 2 1 Department of Anaesthesiology and Intensive Care Unit, 2 Department of Internal Medicine; Cantonal Hospital Zenica, Bosnia and Herzegovina Corresponding author: Adisa Šabanović Adilović Department of Anaesthesiology and Intensive Care Unit, Cantonal Hospital Zenica Crkvice 67, 72 000 Zenica, Bosnia i Herzegovina Phone: +387 32 447 000; Fax: +387 32 226 576; E-mail: adisasabanovic@live.com ORCID ID: https://orcid.org/0000-0002- 1224-8877 Original submission: 06 May 2021; Revised submission: 28 May 2021; Accepted: 07 June 2021 doi: 10.17392/1394-21 Med Glas (Zenica) 2021; 18(2):378-383 ABSTRACT Aim To analyse demographic data, clinical symptoms and signs, laboratory data and comorbidities in patients with COVID-19 pne- umonia admitted to the intensive care unit (ICU), mechanically ventilated with fatal outcome. Methods Medical records of 92 patients were retrospectively analysed. Demographic data, clinical symptoms and comorbidities were collected on the day of hospital admission. Clinical signs and laboratory data were collected on the day of hospital admission (T1), on the day of starting non-invasive ventilation (T2), and on the day of starting invasive ventilation (T3). Results Average age of the patients was 60.05 years. Patients over 50 years of age, 71 (77.1%) (p=0.000), and males, 62 (67.4%; p=0.001) were predominant. The most common patient symp- toms were exhaustion, myalgia, dyspnoea and cough. Hyperther- mia was recorded on the day of hospital admission. Tachycardia, hyperglycaemia, hypoxemia were recorded at all observed study times. The most common comorbidity was hypertension arteria- lis with a very strong correlation with fatal outcome, followed by diabetes mellitus and chronic heart disease that were moderately correlated with fatal outcome. Conclusion The treatment of COVID-19 patients in ICU with mechanical ventilation has a high failure rate. Demographic data, clinical symptoms and signs as well as accompanying comorbi- dities can be a signifcant component in making decisions about diagnostic-therapeutic procedures. Key words: comorbidity, fatal outcome, intensive care unit, inva- sive ventilation