Time-Dependent Changes in Pulmonary Turnover of Thrombocytes During Critical COVID-19.

Publication date: Jul 01, 2024

Under normal conditions, pulmonary megakaryocytes are an important source of circulating thrombocytes, causing thrombocyte counts to be higher in arterial than venous blood. In critical COVID-19, thrombocytes may be removed from the circulation by the lungs because of immunothrombosis, possibly causing venous thrombocyte counts to be higher than arterial thrombocyte counts. In the present study, we investigated time-dependent changes in pulmonary turnover of thrombocytes during critical COVID-19 by measuring arteriovenous thrombocyte differences. We hypothesized that the early stages of the disease would be characterized by a net pulmonary removal of circulating thrombocytes because of immunothrombosis and that later stages would be characterized by a net pulmonary release of thrombocytes as normal pulmonary function is restored. Cohort study with repeated measurements of arterial and central venous thrombocyte counts. ICU in a large university hospital. Thirty-one patients with critical COVID-19 that were admitted to the ICU and received invasive or noninvasive mechanical ventilation. None. We found a significant positive association between the arteriovenous thrombocyte difference and time since symptom debut. This finding indicates a negative arteriovenous thrombocyte difference and hence pulmonary removal of thrombocytes in the early stages of the disease and a positive arteriovenous thrombocyte difference and hence pulmonary release of thrombocytes in later stages. Most individual arteriovenous thrombocyte differences were smaller than the variance coefficient of the analysis. The results of this study support our hypothesis that early stages of critical COVID-19 are characterized by pulmonary removal of circulating thrombocytes because of immunothrombosis and that later stages are characterized by the return of normal pulmonary release of thrombocytes. However, in most cases, the arteriovenous thrombocyte difference was too small to say anything about pulmonary thrombocyte removal and release on an individual level.

Concepts Keywords
Invasive Aged
Normal Blood Platelets
Pulmonary blood platelets
Thirty Cohort Studies
Thrombocytes COVID-19
COVID-19
Female
Humans
Intensive Care Units
Lung
Male
megakaryocytes
Middle Aged
Platelet Count
Respiration, Artificial
respiratory insufficiency
SARS-CoV-2
thromboinflammation
Time Factors

Semantics

Type Source Name
disease VO time
disease MESH COVID-19
disease MESH immunothrombosis
pathway REACTOME Release
disease IDO symptom
disease IDO blood
disease MESH respiratory insufficiency

Original Article

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