Effects of Recombinant Human Thrombopoietin on Platelet Levels in ICU Patients

Inclusion Criteria: * Clinical diagnosis of pneumonia (community acquired pneumonia, hospital acquired pneumonia or ventilator associated pneumonia); * Voluntarily signed informed consent; * ≥18 years old; * Platelet count ≤75×109/L Exclusion Criteria: * A history of hematopoietic stem cell transplantation or solid organ transplantation such as liver, kidney or lung; * Hematological malignancy; * Immune thrombocytopenia, such as SLE, ITP, TTP, etc. * The length of stay in ICU is less than 24h; * Pregnant or lactation patients;