From the Division of Critical Care Medicine, Department of Anesthesiology, University of Michigan, Ann Arbor, Michigan.
Division of Infectious Disease, Department of Internal Medicine, University of Michigan, Ann Arbor, Michigan.
Anesth Analg. 2019 Nov;129(5):1300-1309. doi: 10.1213/ANE.0000000000004072.
The primary objective of this study was to compare the characteristics of culture-positive and culture-negative status in septic patients. We also determined whether culture status is associated with mortality and whether unique variables are associated with mortality in culture-positive and culture-negative patients separately.
Utilizing patient records from intensive care units, emergency department, and general care wards in a large academic medical center, we identified adult patients with suspected infection and ≥2 systemic inflammatory response syndrome criteria between January 1, 2007, and May 31, 2014. We compared the characteristics between culture-positive and culture-negative patients and used binary logistic regression to identify variables independently associated with culture status and mortality. We also did sensitivity analyses using patients with Sequential Organ Failure Assessment and quick Sequential Organ Failure Assessment criteria for sepsis.
The study population included 9288 culture-negative patients (89%) and 1105 culture-positive patients (11%). Culture-negative patients received more antibiotics during the 48 hours preceding diagnosis but otherwise demonstrated similar characteristics as culture-positive patients. After adjusting for illness severity, a positive culture was not independently associated with mortality (odds ratio = 1.01 [95% CI, 0.81-1.26]; P = .945). The models predicting mortality separately in culture-negative and culture-positive patients demonstrated very good and excellent discrimination (C-statistic ± SD, 0.87 ± 0.01 and 0.92 ± 0.01), respectively. In the sensitivity analyses using patients with sepsis by Sequential Organ Failure Assessment and quick Sequential Organ Failure Assessment criteria, after adjustments for illness severity, positive cultures were still not associated with mortality (odds ratio = 1.13 [95% CI, 0.86-1.43]; P = .303; and odds ratio = 1.05 [95% CI, 0.83-1.33]; P = .665), respectively. In all models, physiological derangements were associated with mortality.
While culture status is important for tailoring antibiotics, culture-negative and culture-positive patients with sepsis demonstrate similar characteristics and, after adjusting for severity of illness, similar mortality. The most important factor associated with negative cultures is receipt of antibiotics during the preceding 48 hours. The risk of death in patients suspected of having an infection is most associated with severity of illness. This is aligned with the Sepsis-3 definition using Sequential Organ Failure Assessment score to better identify those suspected of infection at highest risk of a poor outcome.
本研究的主要目的是比较脓毒症患者培养阳性和培养阴性的特征。我们还确定了培养状态是否与死亡率相关，以及培养阳性和培养阴性患者的死亡率是否与独特的变量相关。
利用一家大型学术医疗中心的重症监护病房、急诊室和普通病房的患者记录，我们确定了 2007 年 1 月 1 日至 2014 年 5 月 31 日期间疑似感染且至少有 2 项全身炎症反应综合征标准的成年患者。我们比较了培养阳性和培养阴性患者之间的特征，并使用二元逻辑回归确定与培养状态和死亡率独立相关的变量。我们还使用序贯器官衰竭评估和快速序贯器官衰竭评估标准对脓毒症患者进行了敏感性分析。
研究人群包括 9288 例培养阴性患者（89%）和 1105 例培养阳性患者（11%）。培养阴性患者在诊断前的 48 小时内接受了更多的抗生素，但其他方面与培养阳性患者表现出相似的特征。在调整疾病严重程度后，阳性培养与死亡率无独立相关性（比值比=1.01[95%CI，0.81-1.26]；P=0.945）。分别在培养阴性和培养阳性患者中预测死亡率的模型显示出非常好和极好的区分度（C 统计量±SD，0.87±0.01 和 0.92±0.01）。在使用序贯器官衰竭评估和快速序贯器官衰竭评估标准对脓毒症患者进行的敏感性分析中，在调整疾病严重程度后，阳性培养与死亡率仍无相关性（比值比=1.13[95%CI，0.86-1.43]；P=0.303；比值比=1.05[95%CI，0.83-1.33]；P=0.665）。在所有模型中，生理紊乱与死亡率相关。
虽然培养状态对于调整抗生素治疗很重要，但培养阴性和培养阳性的脓毒症患者具有相似的特征，并且在调整疾病严重程度后，死亡率相似。导致阴性培养的最重要因素是在之前的 48 小时内接受了抗生素治疗。疑似感染患者死亡的风险与疾病严重程度最相关。这与使用序贯器官衰竭评估评分的 Sepsis-3 定义一致，以便更好地识别那些感染风险最高、预后不良的患者。
