The utility of C-reactive protein and procalcitonin for sepsis diagnosis in critically burned patients: A preliminary study.

OBJECTIVE: To assess the utility of C-reactive protein (CRP) and procalcitonin (PCT) as biomarkers of infection in patients with severe burn injury. METHODS: The present study included severe burn injury patients consecutively admitted to the Virgen del Rocío University Hospital (Andalucia, Spain) intensive care unit during a 12-month period. The variables of interest were: age, sex, mechanism of injury, percentage of burned body surface area, the Abbreviated Burn Severity Index (ABSI) and the absence/presence of sepsis. The authors analyzed serum levels of CRP and PCT at admission and every 48 h thereafter until intensive care unit discharge or death. Each determination was considered to be a sample or unit of analysis. RESULTS: A total of 157 determinations were analyzed from 17 severe burn injury patients. Fifty-four samples were considered to be septic, 25 of which corresponded to the first day of a new onset of sepsis. The mean duration of these symptoms was four days (interquartile range two to five days). Significant differences were found in the distributions of CRP and PCT values between sepsis and no-sepsis samples. Analysis of the changes in these biomarkers over time showed that PCT increase (ΔPCT) differentiated these diagnoses, whereas CRP increase (ΔCRP) did not. ROC curve analysis revealed that ΔPCT could predict positive sepsis samples (area under the curve 0.75 [95% CI 0.58 to 0.90]; P=0.003). CONCLUSION: These preliminary results showed that PCT had a better discriminatory capacity than CRP for identifying infectious processes in patients with severe burn injury. A larger sample size would be needed to confirm these results.

OBJECTIF: Évaluer l'utilité de la protéine C réactive (PCR) et de la procalcitonine (PCT) comme biomarqueurs de l'infection chez des grands brûlés. MÉTHODOLOGIE: La présente étude portait sur des grands brûlés admis consécutivement à l'unité de soins intensifs de l'hôpital universitaire Virgen del Rocío d'Andalousie, en Espagne, sur une période de 12 mois. Les variables étudiées étaient l'âge, le sexe, le mécanisme de brûlure, le pourcentage de surface corporelle brûlée, l'indice abrégé de gravité des brûlures (ABSI) et l'absence ou la présence de sepsis. Les auteurs ont analysé les taux sériques de PCR et de PCT des patients à l'admission, puis toutes les 48 heures jusqu'à leur congé des soins intensifs ou à leur décès. Chaque déterminant était considérée comme un échantillon ou une unité d'analyse. RÉSULTATS: Au total, les auteurs ont analysé 157 déterminants chez 17 grands brûlés. Cinquante-quatre échantillons étaient considérés comme septiques, dont 25 correspondaient au premier jour d'apparition du sepsis. Les symptômes duraient en moyenne quatre jours (plage interquartile de deux à cinq jours). Les auteurs ont constaté des différences importantes dans la répartition des valeurs de PCR et de PCT entre les échantillons de sepsis et sans sepsis. L'analyse des changements de ces biomarqueurs au fil du temps a révélé que l'augmentation de la PCT (ΔPCT) distinguait ces diagnostics, contrairement à l'augmentation de la PCR (ΔPCR). L'analyse de la courbe ROC a révélé que la ΔPCT pouvait prédire des échantillons de sepsis positifs (aire sous la courbe de 0,75 [95% IC 0,58 à 0,90]; P=0,003). CONCLUSION: Les résultats préliminaires démontrent que la PCT avait une meilleure capacité discriminatoire que la PCR pour dépister les processus infectieux chez des grands brûlés. Il faudrait un plus gros échantillon pour confirmer ces résultats.

S100B protein may detect brain death development after severe traumatic brain injury.

Despite improvements in the process of organ donation and transplants, the number of organ donors is progressively declining in developed countries. Therefore, the early detection of patients at risk for brain death (BD) is a priority for transplant teams seeking more efficient identification of potential donors. In the extensive literature on S100B as a biomarker for traumatic brain injury (TBI), no evidence appears to exist on its prognostic capacity as a predictor of BD after severe TBI. The objective of this study is to assess the value of including acute S100B levels in standard clinical data as an early screening tool for BD after severe TBI. This prospective study included patients with severe TBI (Glasgow Coma Scale score [GCS] ≤ 8) admitted to our Neurocritical Care Unit over a 30 month period. We collected the following clinical variables: age, gender, GCS score, pupillary alterations at admission, hypotension and pre-hospital desaturation, CT scan results, isolated TBI or other related injuries, Injury Severity Score (ISS), serum S100B levels at admission and 24 h post-admission, and a final diagnosis regarding BD. Of the 140 patients studied, 11.4% developed BD and showed significantly higher S100B concentrations (p<0.001). Multivariate analysis showed that bilateral unresponsive mydriasis at admission and serum S100B at 24 h post-admission had odds ratios (ORs) of 21.35 (p=0.005) and 4.9 (p=0.010), respectively. The same analysis on patients with photomotor reflex in one pupil at admission left only the 24 h S100B sample in the model (OR=15.5; p=0.009). Receiver operating characteristics (ROC) curve analysis on this group showed the highest area under the curve (AUC) (0.86; p=0.001) for 24 h S100B determinations. The cut off was set at 0.372 µg/L (85.7% sensitivity, 79.3% specificity, positive predictive value [PPV]=18.7% and negative predictive value [NPV]=98.9%). This study shows that pupillary responsiveness at admission, as well as 24 h serum S100B levels, could serve as screening tools for the early detection of patients at risk for BD after severe TBI.

Role of early cell-free DNA levels decrease as a predictive marker of fatal outcome after severe traumatic brain injury.

INTRODUCTION: Circulating cell-free DNA levels are increased after trauma injury. This increase is higher since the first hours after trauma and may be related with primary outcome. A sensitive and reliable biomarker for patients at higher risk is needed to identify these patients to initiate early intervention. In this way, circulating DNA may be a possible biological marker after severe TBI. MATERIALS AND METHODS: We investigated DNA plasma concentrations after severe traumatic brain injury and during the next 96 h in the Intensive Care Unit (ICU) by real time PCR. 65 patients suffering severe TBI were included in the study. RESULTS: Cell-free DNA levels were considerably higher in patients samples compared with voluntary control ones. After the following four days we observed a 51% decrease during the first 24h and a 71% fall from 48 h. TBI population was stratified for the primary outcome (survivors/non-survivor) and DNA levels decrease ratio was calculated for the first 48 h. A higher decrease in the survivors from 0 h to 24h compared with the non-survivors was found. A cut-off point of 1.95 ratio was established for the detection of the highest proportions of patients after the TBI that will not survive after the injury with a sensitivity of 70% and specificity of 66%. CONCLUSIONS: In summary we showed that severe TBI is associated with elevated cf-DNA levels and we propose that cf-DNA decrease during the first 24h may predict patient outcome.