BACKGROUND: Infection after severe trauma is a significant cause of morbidity and mortality days to weeks after the initial injury. Apolipoproteins play important roles in host defense and circulating concentrations are altered by the acute inflammatory response. The purpose of this study was to determine if patients who acquire infection after severe trauma have significantly lower apolipoprotein levels than trauma patients who do not become infected.
METHODS: We conducted a case–control study on a prospectively identified cohort of adult patients admitted to our intensive care unit after severe trauma (Injury Severity Score ≥ 16). We compared plasma apolipoprotein levels between patients who acquired an infection within 30 days after trauma (cases) and those that remained infection free (controls).
RESULTS: Of 40 patients experiencing severe trauma, we identified 22 cases that developed an infection within 30 days after injury. Cases had significantly lower posttrauma plasma levels of apolipoprotein B (p = 0.02) and apolipoprotein AII (p = 0.02) compared with controls. Consistent with previous studies, cases also received greater volumes of crystalloid infusions (p < 0.01) and blood transfusions (p < 0.01). Cases also had a more profound inflammatory response as measured by interleukin 6 levels (p = 0.02).
CONCLUSION: Infection after severe trauma is associated with decreased circulating apolipoproteins as compared with uninfected controls. Profoundly decreased plasma apolipoproteins B and AII could potentially contribute to the impaired immunity after severe trauma. Apolipoproteins are potential targets for identifying those patients at risk of infection after trauma and for interventions aimed at preventing nosocomial infections.
LEVEL OF EVIDENCE: Prognostic study, level III.
From the Department of Emergency Medicine (J.K.F., E.K.H.); Department of Surgery (S.D.W.), University of New Mexico Health Sciences Center; Research Service (H.D.G.), New Mexico VA Health Care System; and Department of Pharmaceutical Sciences (P.R.H.), University of New Mexico College of Pharmacy, Research Service, New Mexico VA Health Care System, Albuquerque, New Mexico.
Submitted: May 9, 2012; Revised: November 20, 2012; Accepted: December 4, 2012.
Address for reprints: Jon K. Femling, MD, PhD, Department of Emergency Medicine, University of New Mexico Health Sciences Center, Albuquerque, NM; email: firstname.lastname@example.org.