Key laboratory variations in severe trauma, different natural evolution according to patient phenotype

Abstract

Purpose This study aimed to describe the natural evolution of conventional laboratory parameters in four severe trauma patient phenotypes. Methods An observational analytical study in an intensive care unit (ICU). Patients with severe trauma were included, defined as those having at least one affected anatomical region with an Abbreviated Injury Scale (AIS) of ≥ 3 points. After classification into four relevant groups according to the hemodynamic (HD) status and the presence or absence of major traumatic brain injury (TBI with AIS ≥ 3), evolution of laboratory parameters was described and plotted in a timeline going from patient ICU arrival to time points 24, 48, 72 and 96 hours later. Contrast hypothesis tests were performed for data at the 0 and 24 hour time points. Results A total of 1626 severe trauma patients were included, 80% in the two stable HD groups. Most laboratory differences were found between stable and unstable HD groups, such as lower hemoglobin and platelet count on arrival and after 24 hours, higher lactate and metabolic acidosis from arrival to 24 hours in the most severely ill, low ionized calcium up until 24 hours, and alteration of coagulation only in the most severe subgroup. Differences were also found in patients with major TBI compared with those without, especially in the leukocyte formula. A 24 hours peak in neutrophil-to-lymphocyte ratio was notable in all patients with major TBI, being highest in patients with both unstable HD and major TBI. Conclusion The natural evolution of laboratory parameters differs according to patient phenotype. It completes the picture of hemodynamic status and it also gives insight into the presence of major TBI both in hemodynamically stable or unstable contexts.