59 to 0.78).DiscussionIn this prospective multicenter study on a cohort of ICU-patients with severe pneumonia, median initial PCT levels were elevated inhibitor order us above a normal value of 0.3 ng/ml in all groups. Those patients with ventilator associated pneumonia had the lowest initial PCT values. The maximum PCT levels were observed a median of one to two days after enrolment. Patients with severe CAP had highest initial median PCT values (2.4 ng/ml). These patients also showed greater disease severity, organ dysfunction, and mortality than HAP and VAP. This is in concordance with data from Valencia et al., who reported a mortality rate of 37% in CAP patients requiring ICU therapy [27]. Median admission PCTs of 3.4 ng/ml have been observed in patients presenting with CAP in the emergency department [17].
PCT levels were higher, and remained persistently elevated, in non-survivors. Both, initial and maximum PCT values correlated with the maximum SOFA score and were a reasonable predictor of the risk of death within 28 days in these patients. In patients with severe pneumonia, initial PCT measurement allows a risk stratification similar to the APACHE II-score. The data agree with previous observations. In two studies in the emergency department with more than 1,600 patients each, PCT-values < 0.1 ng/ml in CAP were associated with a low risk of death independent of the clinical risk assessment [17,18]. PCT was also capable of identifying an unfavorable outcome in CAP patients staying at the ICU [28].Impact of PCT-assessment is less well investigated in VAP and HAP compared to CAP.
Patients with HAP not treated in an ICU have low median PCT values of 0.22 ng/ml [29]. In a single center study conducted in 44 patients with VAP, Duflo et al. found PCT to be significantly elevated in non-survivors: The best cut-off for serum PCT in the non-survivors in the VAP group was 2.6 ng/ml with a sensitivity of 74% and a specificity of 75% [7]. Likewise, Luyt et al. found high median PCT levels of about 3 ng/ml at Day 1 in patients with unfavorable outcomes during the clinical course of microbiologically proven VAP (n = 63) [19]. Interestingly, multivariate analyses further supported that serum PCT levels on days 1, 3, and 7 were strong predictors of unfavorable outcome [19].We found a significant association between PCT levels and organ dysfunction as assessed by the SOFA score.
Similar observations were reported by Meisner et al. [30] and by Schroder et al. in surgical critically ill patients [31]. Hedlund et al. showed that the severity of disease measured by the APACHE II score was strongly associated with admission levels of PCT in 96 adult patients with CAP [32]. In 110 patients with CAP, Boussekey et al. found higher PCT levels in bacteremic patients and/or septic shock patients Brefeldin_A (4.9 ng/ml vs. 1.