C reactive protein as marker of infection among patients with severe closed trauma

BACKGROUND. Injury and infection are characterized by the activation of the acute phase proteins response. C-reactive protein (CRP), an acute phase pr otein, has been mentioned as an useful indicator of infection and sepsis in critically ill patients. OBJECTIVE. To study the evolution of serum CRP in patients with severe blun t trauma and to ascertain its ability as a biological marker of infection d uring the first seven days after injury. METHODS. We prospectively studied 54 patients with blunt trauma (injury sev erity score greater than or equal to 16) age>14 years and length of the Int ensive Care Unit (ICU) estay greater than or equal to 7 days, over a 4-mont h period. Culture-proven infections were collected and serum CRP was determ inated every day, during the first week after ICU admission. RESULTS. Twenty-eight patients (51.8%) developed an infection during the fi rst week, and the median day of diagnosis of infection was day 6. Pneumonia was the most common infection (50%) and Gram-negative bacilli (63.3%) were the most common microorganisms recovered. Serum CRP levels were significan tly higher in the infected patients group after day 4, showing a median val ue higher than 170 mg/l. Based on the receiver operating characteristic (RO C) curve analysis, a cutoff value of 109.5 mg/l for CRP gives a sensitivity of 78.6% and a specifity of 73.1% in predicting the presence of infection. CONCLUSIONS. The course of serum CRP levels is different in the group of pa tients with severe blunt trauma and infection, compared with the non-infect ed group during the first week after injury and it could be an useful suppl ementary marker for infection after postinjury day 4. A value of 110 mg/l o r higher for CRP should suggest an underlying infectious complication.