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[每周一问]NO.22-Intravascular Catheter Related Infections

This week we'll be discussing intravascular catheter related infections. Seemingly benign, this entity results in significant morbidity and mortality. Today we'll discuss basic facts regarding these infections.
1.  What is the incidence of catheter related infections?
2.  What is the cost associated with these catheter related infections?
3.  What pathways do microbes utilize to establish an infection?
4.  How can catheters be implicated as the etiology of an infections?
本周我们将讨论血管内导管相关性感染。表面上看似乎没有危险，但实际上可导致明显的发病率和死亡率。今天我们讨论与之相关的基本因素。
1.  导管相关性感染的发生率有多少？
2.  与费用有关的导管相关性感染指什么？
3.  微生物通过什么途径导致感染？
4.  导管与感染病原学的关系？

Guidelines for the Prevention of Intravascular Catheter-Related Infections
参考答案
1.导管相关性感染的发生率为多少？
导管相关性感染每年的确切数字和发生率尚不知道。报道不全是这些数据有限的主要原因，而并非发生罕见，其原因部分是由于中央数据库的缺乏。ICU感染数可作为导管感染的代表进行统计，并可以通过推断美国医院协会关于ICU病床利用率和疾控中心关于每导管天数血流感染率来进行估计。这些数据的计算机模型估计出每年发生在美国ICU中血流感染相关的中心导管感染有16，000例[1]。
2.与成本有关的导管相关性感染指什么？
导管相关性感染的发病和死亡的费用并不准确。从费用上来说，在澳大利亚导管相关的菌血症的单个事件的费用大约50，000美元[2]，在美国为3700-29，000之间[3]。每年在美国，仅仅在ICU中的中心静脉导管感染的费用就达到6000万-4.6亿美元！此外，在前瞻性研究中发现，这些感染的死亡率发生率约为12-25%[4，5]。
3.微生物通过什么途径导致感染？
大多数微生物通过从导管注射部位或经皮肤移行入管腔造成感染。少见的是，输入污染的液体或远隔部位感染的血源播散可导致导管相关性感染[1]。
4.导管是如何与感染病原学有关的？
经皮穿刺血培养，与有关导管的细菌生长进行比较发现，明确了导管相关血流感染的诊断[1]。临床感染症状的存在、随后退热药物对培养敏感细菌的治疗和消除可协助诊断[2]。
What is the incidence of catheter related infections?
The total number and incidence of catheter related infections occurring each year is unknown. Underreporting, rather than infrequency, represents the main cause for this limited data, in part due to the lack of centralized databases. The number of central line infections in an ICU setting can be used as a representative surrogate and can be estimated by extrapolating the data from the American Hospital Association regarding ICU bed utilization and the Centers for Disease Control regarding bloodstream infections per catheter days. Computer modeling of these data has estimated that 16,000 central line associated bloodstream infections occur in ICUs in the United States each year (1).
What is the cost associated with these catheter related infections?
The morbidity and mortality costs from catheter related infections are imprecise. In terms of costs, a single episode of catheter-related bacteremia has an estimated cost of $50,000 in Australia (2) and between $3700 and $29,000 in the US (3). Annually, these costs total $60 to $460 million for just central venous catheter infections in ICU settings in the US alone! In addition, mortality from these infections have been reported to occur in 12-25% of patients in prospective studies (4,5).
What pathways do microbes utilize to establish an infection?
Most microbes infect catheters by migrating intraluminally from colonized hubs, or extraluminally from colonized skin. Less commonly, contaminated infusates or hematogenously spread microbes from distant infections have been noted to create catheter related infections (1).
How can catheters be implicated as the etiology of an infections?
The growth of percutaneously drawn blood cultures which match the microbial growth from the involved catheter confirms the diagnosis of catheter-related bloodstream infections (1). The presence of clinical symptoms of infection and subsequent defervescence with removal and treatment of culture sensitive microbes may assist in making the diagnosis (2).
References:
1.  Mermel LA. Prevention of intravascular catheter-related infections. Ann Intern Med. 2000;132(5):391-402.
2.  Fraenkel DJ, Rickard C, Lipman J. Can we achieve consensus on central venous catheter-related infections? Anaesth Intensive Care. 2000;28(5):475-90.
3.  Arnow PM, Quimosing EM, Beach M. Consequences of intravascular catheter sepsis. Clin Infect Dis. 1993;16:778-84.
4.  Collignon PJ. Intravascular catheter associated sepsis: a common problem. The Australian Study on Intravascular Catheter Associated Sepsis. Med J Aust. 1994;161:374-8.
5.  Heiselman D. Nosocomial bloodstream infections in the critically ill. JAMA. 1994;272(23):1819-20.
Site Editor: Stephen B. Corn, M.D. and B. Scott Segal, M.D.
Department of Anesthesia, Harvard Medical School