Serum Procalcitonin, but not C-reactive Protein, Identifies Sepsis in Trauma Patients

¹ Service de Biochimie B, Institut Gustave Roussy, 94805 Villejuif, France, ,
² Service d'Anesthésie-Réanimation, Centre Hospitalier de Bicêtre, 94275 Le Kremlin Bicêtre, France

To the Editor:

Trauma is a major cause of a biphasic Systemic Inflammatory Response Syndrome (SIRS), making the clinical diagnosis of infection difficult, especially during the late inflammatory phase (around day 7) (1). A biological indicator is needed to reinforce the presumption and to indicate specific bacterial examinations. Serum procalcitonin (PCT) is related to the evolution of infection in a medical setting (2). We presently report serum PCT during the late posttraumatic phase when infections usually occur (3), and we compare the informative value of PCT to that of C-reactive protein (CRP).

Consecutive severe [Injury Severity Score (ISS) >16] and young (age <55 years) trauma patients without previous chronic disease, admitted to our Surgical ICU between January 1, 1996, and April 30, 1996, were included in the study. Each day, patients were classified as exhibiting SIRS or sepsis according to the previously proposed definitions (4). Each patient was examined daily for the presence of infection. Blood cultures (three times a day) and urine cultures (twice a week) were systematically done in patients exhibiting SIRS, and specific bacteriological examinations were performed when indicated. Bacterial infections were defined according to the criteria of the Centers for Disease Control (5). Blood sampling was done at day 7 for determination in duplicate of CRP and PCT serum concentrations. CRP was measured by rate nephelometry immunoassay with a Beckman Array System (Beckman Instruments; upper reference limit in our population <6 mg/L). PCT was measured by an immunoluminometric assay (LUMItest PCT, Brahms Diagnostica; normal value <0.5 µg/L). Comparison between the clinical status of patients and the biological indicators was performed by the Kruskal–Wallis rank test, followed if indicated by a Mann–Whitney U-test. A P value <0.05 was considered to be significant.

Twenty-one patients were included [ages, 29 (20–52); ISS, 27 (17–48), median and range]; one patient died at day 4. At day 7, 12 patients exhibited a SIRS; 4 patients exhibited a SIRS related to an infection (i.e., a sepsis) documented between day 5 and day 8: two bacteremic pneumonias (Escherichia coli and Pseudomonas aeruginosa) and two bacteremias (Enterobacter cloacae). As shown in Fig. 1 , the median values of PCT and CRP were higher during sepsis than either during SIRS or absence of inflammation. However, a clear overlapping of CRP values was observed between septic and nonseptic patients, in contrast to PCT results, because CRP was increased in 17 out of the 20 survivors whatever the clinical status.

View larger version (23K): [in this window] [in a new window]   Figure 1. Comparison of serum procalcitonin (A) and C-reactive protein (B) relative concentrations between the three groups of trauma patients, according to their clinical status on day 7 of stay. No SIRS, absence of inflammatory syndrome; SIRS, Systemic Inflammatory Response Syndrome; Sepsis, SIRS related to infection.

Sepsis may lead to a lethal multiple organ failure in trauma patients, especially in cases of delayed diagnosis of infection. A secondary increase in serum PCT seems to be an adequate indicator of severe and/or bacteremic infection during the late posttraumatic SIRS, in contrast to the classical acute phase protein, CRP. Indeed CRP, is increased for at least 2 weeks after severe injury in the absence of sepsis (6). A significant increase in PCT may justify a complete bacteriological screening (7) in trauma patients.

Footnotes

*Author for correspondence. Fax 33-1-45-21-28-75; e-mail darkb{at}imaginet.fr

References

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