Prehospital Hypotension Is Associated With Altered Inflammation Dynamics and Worse Outcomes Following Blunt Trauma in Humans.

OBJECTIVE: To define the impact of prehospital hypotension on the dynamic, systemic acute inflammatory response to blunt trauma.

DESIGN: Retrospective study.

SETTINGS: Tertiary care institution.

PATIENTS: Twenty-two hypotensive blunt trauma patients matched with 28 normotensive blunt trauma patients.

INTERVENTION: None.

MEASUREMENTS AND MAIN RESULTS: From a cohort of 472 blunt trauma survivors studied following institutional review board approval, two stringently matched subcohorts were derived. Twenty-two patients who sustained prehospital hypotension following blunt trauma (15 males and 7 females; age, 45 ± 3.8; Injury Severity Score, 20.7 ± 1.8) were matched with 28 normotensive trauma patients (20 males and 8 females; age, 46.1 ± 2.5; Injury Severity Score, 20.8 ± 1.3). Serial blood samples (three samples within the first 24 hr and then from days 1 to 7 postinjury) were assessed for 24 inflammatory mediators using Luminex, and No2-/No3- was measured using the nitrate reductase/Griess assay. Two-way analysis of variance was used to compare groups. Dynamic Bayesian Network inference was used to infer causal relationships based on probabilistic measures. Statistically significant differences were observed in ICU length of stay, total length of stay, days on mechanical ventilator, and Marshall Multiple Organ Dysfunction score between hypotensive and normotensive patients. Shock markers (shock index, pH, lactate, and base deficit) were significantly altered in hypotensive patients. Plasma levels of chemokines (monocyte chemotactic protein-1/CCL2, inducible protein-10/CXCL10, macrophage inflammatory protein-1α/CCL3, and interleukin-8/CCL8) and cytokines (interleukin-6, interleukin-10, interleukin-17, granulocyte-macrophage colony-stimulating factor, interleukin-1β, and interleukin-7) as well as soluble interleukin-2 receptor-α were significantly elevated over the first 7 days postinjury in the hypotensive versus normotensive patients. Dynamic Bayesian Network suggested that the chemokines monocyte chemotactic protein-1/CCL2 and monokine induced by gamma interferon/CXCL9 in the hypotensive and normotensive patients, respectively, affect plasma interleukin-6 levels differentially in the initial 24 hours postinjury.

CONCLUSIONS: Studies in stringently matched patient cohorts suggest that an episode of prehospital hypotension post trauma leads to early, dynamic reprogramming of systemic inflammation (including differential upstream regulation of interleukin-6), which is associated with worse outcomes.