Hemoglobin Trends as a Predictor of Outcomes in Critically Ill Patients (The TRENT-ICU Study)

The goal of this observational study is to evaluate if early absolute hemoglobin decline (during the first 24 hours of admission) can predict prolonged intensive care unit stay (8 days or more) and in-hospital mortality in critically ill adult patients. The main questions it aims to answer are: Does absolute hemoglobin decline during the first 24 hours of admission independently predict prolonged intensive care unit stay in critically ill adult patients? Does absolute hemoglobin decline during the first 24 hours of admission independently predict in-hospital mortality in critically ill adult patients? Participants will: Have their routine clinical and laboratory data reviewed retrospectively from their electronic health records (including baseline hemoglobin and a second hemoglobin determination approximately 24 hours after admission). No additional interventions or extra blood draws will be performed beyond routine clinical care.