The aim of this study is to investigate the prevalence and possible risk factors of the occurrence of a DVT in 12 intubated and mechanically ventilated COVID-19 patients admitted to the ICU at a single time point (29/03/2020).

Patients admitted to the Intensive Care Unit (ICU) are known to be at risk for thrombo-embolic events. Virchow's triad describes the major risk factors in three categories: venous stasis, vessel injury and activation of blood coagulation. A prolonged mechanical ventilation together with the hemodynamic effects of this ventilation with a high positive and expiratory pressure (PEEP), the presence of central venous catheters, the immobilization of these patients and the presence of obesity or other comorbidities can attribute to the occurrence of a deep venous thrombosis (DVT) in patients admitted at ICU. The incidence of DVT during ICU stay has been reported between 5 and 15%.

On the 13th of March, the first COVID-19 patient was admitted at the ICU at the Jessa Hospital. Within a few days, the admissions at our COVID-19 unit grew exponential. In these difficult time, research concerning COVID-19 has been performed indicating the COVID-19 virus induces a hyper-inflammatory state. It has been suggested that systemic inflammation induces endothelial injury. This will activate the coagulation cascade and impair fibrinolysis with disruption of endothelial barrier, and loss of physiologic antithrombotic factors which may elevated the risk for DVTs significantly. Up to now, there is still no causal treatment for COVID-19. The current management of COVID-19 is mainly supportive i.e. a prolonged inflammatory status and a prolonged risk for VTE.

During the placement of a dialysis catheter in the femoral vein of one of the patients admitted in the ICU for COVID-19 at our hospital, a large deep vein thrombosis (DVT) proximal in both common femoral veins was noticed in a patient. Since there were no clinical signs of DVT present in this patient, every patient at the ICU unit at that moment was screened on the presence of DVTs. We found one or several deep vein thromboses in 8 out of 12 patients at 1 ICU unit. Since this was a unusual high incidence, we want to further investigate this prevalence and evaluate possible causes of these DVTs.

The aim of this study is to investigate the prevalence and possible risk factors of the occurrence of a DVT in 12 intubated and mechanically ventilated COVID-19 patients admitted to the ICU at a single time point (29/03/2020).

The endpoint of this cross-sectional study is to investigate the prevalence and identify possible risk factors of the occurrence of a DVT in these patients at the ICU.

These parameters are listed below and included parameters/values collected as a standard-of-care in our hospital:

• Demographics: i.e age, gender
• Comorbidities: smoking, hypertension, diabetes, cardiovascular disease, respiratory disease, malignancies, renal failure, liver failure, gastrointestinal disease, neurological conditions, mental state, other
• Symptoms at the time of admission to ICU: i.e fever, body temperature, dyspnoea, headache, diarrhea etc…
• Laboratory results of all standard parameters measured
• Treatment: antiviral agents, antibiotics, etc…
• Complications: shock, heart failure, sepsis, stroke, etc…
• Ventilation: method, PEEP, FiO2, ..
• Radiological findings: pneumonia, ground-glass opacity..

Inclusion Criteria:

• 12 intubated and mechanically ventilated COVID-19 patients admitted to the ICU at a single time point (29/03/2020).

Exclusion Criteria:

• None

12 intubated and mechanically ventilated COVID-19 patients admitted to the ICU at a single time point (29/03/2020).