Department of Intensive Care Medicine, Peking Union Medical College Hospital, Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing100730, China.
Chin Med J (Engl). 2013;126(10):1832-7.
Rapid detection of bacteremia is important for critically ill patients. Procalcitonin (PCT) has emerged as a marker of sepsis, but its characterization for predicting bacteremia is still unclear. This study aimed to investigate the role of change of PCT within 6 to 12 hours after new fever in predicting bacteremia.
An observational study was conducted in the ICU of our hospital from January 2009 to March 2010. Adult patients with new fever were included and grouped as bacteremia and non bacteremia group. Serum PCT concentration was measured at admission and within 6 to 12 hours after new fever (designated PCT0 and PCT1). Other results of laboratory tests and therapeutic interventions were recorded. Multivariate Logistic regression analysis was used to identify the risk factors of bacteremia. The area under the ROC curve (AUC) was constructed to evaluate the discriminative power of variables to predict bacteremia.
Totally 106 patients were enrolled, 60 of whom had bacteremia and 46 did not have bacteremia,. The acute physiology and chronic health evaluation II (APACHE II) and sequential organ failure assessment (SOFA) scores were 13.1 ± 7.8 and 5.0 ± 2.2 at admission, respectively. There was no significant difference in PCT0 between the bacteremia group and nonbacteremia group; 1.27 µg/L (range, 0.10 - 33.3) vs. 0.98 µg/L (range, 0.08 - 25.7), (P = 0.157). However, the PCT1 and the rate of change of PCT were significantly higher in bacteremia group; PCT1 was 6.73 µg/L (1.13 - 120.10) vs. 1.17 µg/L (0.10 - 12.10) (P = 0.001), and the rate of change was 5.62 times (1.05 - 120.6) vs. 0.07 times (-0.03 - 0.18) (P < 0.001). The area under the ROC curve (AUC; 95% confidence interval) of the rate of change of PCT was better for predicting bacteremia than that of PCT1; 0.864 (range, 0.801 - 0.927) vs. 0.715 (range, 0.628 - 0.801), (P < 0.05). The AUCs of PCT0 and other parameters (such as WBC count, granulocyte percentage and temperature) were not significantly different (all P > 0.05). The best cut-off value for the rate of change was 3.54 times, with a sensitivity of 88.5% and a specificity of 98.0%. It was also an independent predictor of bacteremia (odds ratio 29.7, P < 0.0001) and wasn't correlated with the presence or absence of co-infection, neutropenia or immunodeficiency (P > 0.05).
The rate of change of PCT is useful for early detection of bacteremia during new fever and superior to the PCT absolute value and other parameters in non-selected ICU patients.
快速检测菌血症对危重症患者非常重要。降钙素原（PCT）已成为脓毒症的标志物，但预测菌血症的特征仍不清楚。本研究旨在探讨新发热后 6 至 12 小时内 PCT 变化对菌血症的预测作用。
2009 年 1 月至 2010 年 3 月，我们在我院 ICU 进行了一项观察性研究。纳入新发发热的成年患者，并分为菌血症和非菌血症组。入院时和新发热后 6 至 12 小时（分别命名为 PCT0 和 PCT1）测定血清 PCT 浓度。记录其他实验室检查结果和治疗干预措施。采用多变量 Logistic 回归分析确定菌血症的危险因素。构建 ROC 曲线下面积（AUC）评估变量预测菌血症的判别能力。
共纳入 106 例患者，其中 60 例发生菌血症，46 例未发生菌血症。入院时急性生理学与慢性健康状况评分系统 II（APACHE II）和序贯器官衰竭评估（SOFA）评分分别为 13.1 ± 7.8 和 5.0 ± 2.2。菌血症组和非菌血症组 PCT0 无显著差异；1.27 µg/L（范围，0.10 - 33.3）与 0.98 µg/L（范围，0.08 - 25.7），（P = 0.157）。然而，PCT1 和 PCT 变化率在菌血症组中明显更高；PCT1 为 6.73 µg/L（1.13 - 120.10）与 1.17 µg/L（0.10 - 12.10）（P = 0.001），变化率为 5.62 倍（1.05 - 120.6）与 0.07 倍（-0.03 - 0.18）（P < 0.001）。PCT 变化率的 AUC（95%置信区间）优于 PCT1 预测菌血症；0.864（范围，0.801 - 0.927）与 0.715（范围，0.628 - 0.801），（P < 0.05）。PCT0 和其他参数（如白细胞计数、粒细胞百分比和体温）的 AUC 无显著差异（均 P > 0.05）。PCT 变化率的最佳截断值为 3.54 倍，灵敏度为 88.5%，特异性为 98.0%。它也是菌血症的独立预测因子（比值比 29.7，P < 0.0001），与合并感染、中性粒细胞减少或免疫缺陷无关（P > 0.05）。
PCT 变化率有助于早期发现新发热时的菌血症，优于 PCT 绝对值和非选择 ICU 患者的其他参数。
