Steiner C K, Stewart D L, Bond S J, Hornung C A, McKay V J
Division of Neonatology, Department of Pediatrics, Center for Health Services and Policy Research, University of Louisville School of Medicine, Louisville, KY 40202-3830, USA.
J Pediatr Surg. 2001 Mar;36(3):487-92. doi: 10.1053/jpsu.2001.21609.
The aim of this study was to identify independent predictors of acquiring a nosocomial bloodstream infection (BSI) during extracorporeal membrane oxygenation (ECMO).
This retrospective cohort consisted of 202 neonates treated with ECMO from 1989 to 1998 at the author' institution. Data collected included patient demographics, primary and secondary diagnoses, white blood cell counts, antibiotic usage, presence of central lines, operative procedures, and outcome. Surveillance blood cultures were drawn daily from the circuit using sterile technique to identify acquired pathogens. Statistical analyses included logistic regression, Cox proportional regression analysis, and discriminate analysis.
There were 1,245 blood cultures drawn on 202 patients (6.2 cultures per patient), and a nosocomial BSI was identified in 7 patients (3.4%) during this 10-year span. These were infections that were neither present nor incubating on admission. Pre-ECMO diagnoses of patients who had a nosocomial BSI while on bypass included group B beta-hemolytic streptococcal sepsis (n = 2), herpes simplex viral sepsis (n = 1), congenital diaphragmatic hernia (n = 2), persistent pulmonary hypertension (n = 1), and congenital heart disease (n = 1). The median time on ECMO before obtaining a positive culture was 390 hours. The infectious agents responsible for these BSIs included Staphylococcus epidermidis (n = 5), Staphylococcus aureus (n = 1), and Escherichia coli (n = 1). The major factor associated with acquiring a nosocomial BSI on ECMO was the duration of bypass (391 v 141 hours, P =.002). Additionally, patients in the BSI group were more likely to have had an arterial catheter in place (16 v 7 days, P =.009) and to have received more screening blood cultures (16 v 6 cultures, P < 001). White blood cell counts, absolute neutrophil counts, and immature/total (I/T) ratios were not useful in predicting a nosocomial BSI. Of the 31 patients who required ECMO for more than 10 days, 7 (23%) had a positive blood culture, and 5 of these 7 infants (71%) died (P =.03).
The only predictor of acquiring a nosocomial BSI on ECMO was the duration of support for greater than 10 days. Because classical predictors of infection are unreliable while the patient is on ECMO, the authors suggest that obtaining daily surveillance blood cultures beginning on the tenth day should be performed with prolonged ECMO courses. The authors confirmed previous reports of the association between a prolonged ECMO course and a high mortality rate. However, the authors speculate that, in actuality, the primary diagnosis leads to the prolonged course of support and is the major factor in the infant' demise.
本研究旨在确定体外膜肺氧合（ECMO）期间获得医院血流感染（BSI）的独立预测因素。
该回顾性队列研究包括1989年至1998年在作者所在机构接受ECMO治疗的202例新生儿。收集的数据包括患者人口统计学、原发性和继发性诊断、白细胞计数、抗生素使用情况、中心静脉置管情况、手术操作及结局。采用无菌技术每天从循环管路采集监测血培养标本以鉴定获得性病原体。统计分析包括逻辑回归、Cox比例回归分析和判别分析。
对202例患者共采集了1245份血培养标本（平均每名患者6.2份），在这10年期间7例患者（3.4%）被鉴定为医院BSI。这些感染在入院时既不存在也未处于潜伏期。在体外循环期间发生医院BSI的患者，其ECMO前诊断包括B族β溶血性链球菌败血症（n = 2）、单纯疱疹病毒败血症（n = 1）、先天性膈疝（n = 2）、持续性肺动脉高压（n = 1）和先天性心脏病（n = 1）。获得阳性培养结果前ECMO的中位时间为390小时。导致这些BSI的病原体包括表皮葡萄球菌（n = 5）、金黄色葡萄球菌（n = 1）和大肠杆菌（n = 1）。与在ECMO上获得医院BSI相关的主要因素是体外循环时间（391小时对141小时，P = 0.002）。此外，BSI组患者更可能留置动脉导管（16天对7天，P = 0.009）且接受更多的筛查血培养（16次对6次培养，P < 0.001）。白细胞计数、绝对中性粒细胞计数和未成熟/总（I/T）比值对预测医院BSI无用。在31例需要ECMO支持超过10天的患者中，7例（23%）血培养阳性，这7例婴儿中有5例（71%）死亡（P = 0.03）。
在ECMO上获得医院BSI的唯一预测因素是支持时间超过1〇天。由于在患者接受ECMO期间传统的感染预测指标不可靠，作者建议对于延长的ECMO疗程，应从第10天开始每天进行监测血培养。作者证实了先前关于延长ECMO疗程与高死亡率之间关联的报道。然而，作者推测，实际上，原发性诊断导致了延长的支持疗程，并且是婴儿死亡的主要因素。
