¹Department of Trauma, Hand, Plastic and Reconstructive Surgery, Ulm University, Ulm, Deutschland
²Institute of Clinical and Experimental Trauma Immunology, Ulm University, Ulm, Deutschland

Text

Objectives and questions: Lymphopenia and a progressive decline in lymphocyte levels have been linked to poor clinical outcomes in trauma patients. However, no standardized method currently exists to monitor immune responses effectively or to identify patients at risk of developing lymphopenia and subsequent complications. The Absolute Lymphocyte Count (ALC) is a biomarker that could address this gap and aid in clinical decision-making in the Intensive Care Unit (ICU). This study examines the temporal patterns of ALC in polytrauma patients and its association with clinical outcomes.

Material and methods: We conducted a prospective study enrolling 38 polytrauma patients with an Injury Severity Score (ISS) of 18 or higher. Blood samples were collected at admission and consecutively over 10 days. A control group of 38 healthy volunteers was included for comparison. Based on their ALC dynamics at 48 hours, patients were categorized into four groups: persistent lymphopenia (PL), rapidly decreasing (RD), slowly rising (SR), and normal fluctuation (NF). Clinical outcomes assessed included physical performance, in-hospital mortality, ICU length of stay (LOS), and the incidence of multi-organ dysfunction syndrome (MODS). A favorable physical performance outcome was defined as discharge home, while an unfavorable outcome included new functional disability requiring long-term care or death.

Results: Over the 10-day study period, all trauma patients exhibited significantly lower ALC levels than healthy controls. Patients in the PL and RD groups had a higher likelihood of unfavorable physical performance outcomes (PL: 80%; RD: 80%; p=0.008), prolonged ICU LOS (PL: 70% and RD: 70% required ICU stay ≥7 days; p=0.049), increased MODS incidence (PL: 80%; RD: 50%; p=0.08), and elevated in-hospital mortality (PL: 20%; RD: 40%; p=0.09). In contrast, patients in the NF and SR groups were more likely to achieve favorable physical performance outcomes, have shorter ICU stays, and experience lower rates of MODS.

Discussion and conclusions: Monitoring ALC dynamics within the first 48 hours post-trauma is a more effective predictor of clinical outcomes than single-time-point ALC measurements. The temporal trajectory of ALC is a cost-effective, clinically viable tool for immunomonitoring in polytrauma patients. Early identification of patients at risk for adverse outcomes may facilitate timely interventions and improve trauma care.