Cordero L, Coley B D, Hogan M J, Ayers L W
The Ohio State University College of Medicine, Columbus, USA.
J Perinatol. 1998 Jul-Aug;18(4):291-6.
The objective of the study was to characterize the changes that occur in chest radiographs at the time of gram-negative bacilli (GNB) nosocomial bloodstream infection (BSI) and to determine the contribution of bronchopulmonary dysplasia (BPD) and airway gram-negative bacterial pathogens to the clinical diagnosis of GNB nosocomial pneumonia.
This retrospective investigation involved 41 BSI infants (study group) and 50 GNB airway colonized infants who had sepsis workup with negative blood cultures (control group). We correlated clinical findings (95 blood and 305 tracheal aspirate (TA) cultures) with radiographic findings noted within 2 days before, the day of, and the day after blood cultures. Two radiologists independently graded 258 films using a modified score for BPD and a semiquantitative score ("probable," "possible," or "unlikely") for pneumonia.
Mean birth weight was 1057 gm and 1044 gm for the study and control groups, respectively. Of the study population, 54% were male, 21% were black, 89% received surfactant, 79% received dexamethasone, and 88% survived. Average age at the time of blood cultures for both groups was 23 days. Most common isolates from blood and TA were Klebsiella pneumoniae, Enterobacter cloacae, Escherichia coli, and Pseudomonas aeruginosa. Eight BSI infants died, mainly as a result of P. aeruginosa and K. pneumoniae; three control patients also died. Radiological findings were that BPD scores did not change in relation to BSI and were similar between study and control groups. Of the BSI patients, 21 presented with newly positive TA at the time of positive blood culture; "probable" or "possible" pneumonia was diagnosed in 18 of them. Their BPD scores were higher than those of the remaining BSI patients, of whom seven were already airway colonized, nine had negative TAs, and four were not intubated. Only one of these 20 patients had "possible" pneumonia noted on chest x-ray films.
Radiographic signs of air space disease accompanied by the recovery of GNB respiratory pathogens from the blood and from a previously uncolonized airway strongly support the clinical diagnosis of GNB nosocomial pneumonia. Radiological signs of BPD are stable in relation to nosocomial BSI caused by GNB, but BPD radiological scores are higher among infants who also had a newly acquired respiratory GNB. BSI, new respiratory tract GNB, and BPD are critical associations for the clinical interpretation of radiographic changes in the ventilated newborn.
本研究的目的是描述革兰氏阴性杆菌（GNB）医院获得性血流感染（BSI）时胸部X线片出现的变化，并确定支气管肺发育不良（BPD）和气道革兰氏阴性菌病原体对GNB医院获得性肺炎临床诊断的作用。
这项回顾性调查纳入了41例BSI婴儿（研究组）和50例GNB气道定植婴儿，后者接受了败血症检查但血培养结果为阴性（对照组）。我们将临床检查结果（95份血液和305份气管吸出物（TA）培养）与血培养前2天、血培养当天及血培养后1天记录的影像学检查结果进行关联分析。两名放射科医生使用改良的BPD评分和肺炎的半定量评分（“可能”“有可能”或“不太可能”）对258张胸片进行独立分级。
研究组和对照组的平均出生体重分别为1057克和1044克。在研究人群中，54%为男性，21%为黑人，89%接受过表面活性剂治疗，79%接受过地塞米松治疗，88%存活。两组血培养时的平均年龄均为23天。血液和TA中最常见的分离菌为肺炎克雷伯菌、阴沟肠杆菌、大肠埃希菌和铜绿假单胞菌。8例BSI婴儿死亡，主要原因是铜绿假单胞菌和肺炎克雷伯菌感染；3例对照组患者也死亡。影像学检查结果显示，BPD评分与BSI无关，研究组和对照组相似。在BSI患者中，21例在血培养阳性时TA新出现阳性；其中18例被诊断为“可能”或“有可能”肺炎。他们的BPD评分高于其余BSI患者，其余患者中7例已有气道定植，9例TA为阴性，4例未插管。这20例患者中只有1例胸部X线片显示“有可能”肺炎。
气腔疾病的影像学征象，同时伴有从血液和先前未定植的气道中分离出GNB呼吸道病原体，强烈支持GNB医院获得性肺炎的临床诊断。BPD的影像学征象在由GNB引起的医院获得性BSI中较为稳定，但在同时新获得呼吸道GNB的婴儿中，BPD影像学评分更高。BSI、新的呼吸道GNB和BPD是对通气新生儿影像学变化进行临床解读的关键关联因素。
