使用CT或超音波防止不必要的阑尾切除术


  【24drs.com】使用诊断性计算机断层(CT)和/或超音波,可以让10岁以上的男女幼童较少进行不必要的阑尾切除术,不过,根据对40所儿童医院之急诊阑尾炎诊断病童进行的5年回溯评估,这些影像技术对5岁以上男孩的效果有限。
  
  波士顿儿童医院急诊部主任Richard G. Bachur医师等人在4月16日的小儿科期刊在线发表他们的研究报告。
  
  Bachur医师等人确认了CT和超音波用于诊断阑尾炎的准确度,针对每种影像检查方法、根据性别和年龄分组(<5岁、5 – 10岁、>10岁),计算负向阑尾切除术比率(NARs),所谓的负向阑尾切除术是指手术切除了正常阑尾。
  
  研究者希望比较CT和超音波影像,是因为一般认为CT比较好,但是病患得曝露于离子射线;放射线曝露和增加终生癌症风险有关,超音波是另一个可行的替代方式,特别是孩童。
  
  NARs的计算方式是,进行阑尾切除术但最后没有阑尾炎诊断之急诊病患数除以接受阑尾切除术的所有急诊病患数。
  
  研究者计算CT和超音波影像与负向阑尾切除术之结果间的关联,分析方式是线性回归分析,使用医院层级的NAR作为依变项,医院层级的影像率作为独立变项,以各医院进行的阑尾切除术加权;他们根据各年龄和性别分组进行这项分析,校正每个机构的病患量。
  
  在8,959,155例急诊病患中,55,227名孩童最后诊断有阑尾炎,这些孩童中,35,335人(64.0%)属于无并发症的阑尾炎,13,166人(23.8%)有阑尾穿孔,6.26人(12.2%)有阑尾穿孔且形成脓疡;进行阑尾切除术的52,290名病患中,96.4%最后有阑尾炎诊断,NAR比率为3.6%。
  
  每个性别年龄小组,CT比率都高于超音波比率;每个小组中,接受影像检查的女孩比男孩多,5岁以下孩童更可能进行CT和超音波。NARs比率最高的是5岁以下孩童和10岁以上女孩。除了5岁以下孩童,其它各小组中,各个机构使用的CT和/或超音波比率与机构的NAR之间有显著关联。CT比率本身而言,与各小组的机构NAR没有关联。NAR最低的是5岁以上男孩,不论影像方法为何。
  
  5岁以上男孩的NAR低于5岁以下男孩。阑尾切除术前的CT只和5岁以下男孩的NAR较低有显著关联,使用超音波和5岁以下男孩NAR较高有关。5岁以下女孩中,CT和NAR较低有显著关联,但是如果使用超音波,则NAR无差异。
  
  与男孩(1.1%)相比,10岁以上女孩的NAR显著较高(5.5%),与影像检查方式无关(校正胜算比5.2;95%信心区间4.4 - 6.1)。
  
  作者们写道,目前的研究结果认为,需将年纪和性别整合纳入任何的评估计画而进行临床处置。
  
  因为5岁以上男孩不论哪里种影像检查方式的NAR都最低,作者们认为,CT和超音波对这个小组的效果有限。作者们写道,需注意,矛盾的是,5岁以下男孩进行超音波时的NAR反而较高(与没有进行超音波者相比),或许反映出,对这年龄层而言,试图依赖超音波而非CT是更困难的。
  
  作者们写道,10岁以上女孩的NAR较高,可能是因为某些妇科情况,使影像结果看来象是阑尾炎。虽然负向阑尾切除术相对比率高,如同原本认知的,青春期后女孩使用影像检查和负向阑尾切除术绝对减少值最大有关。
  
  作者们结论表示,CT和超音波使5岁以下孩童和10岁以上女孩的NARs减少更多,但是对于疑似阑尾炎且无其它临床问题之5岁以上男孩的效果有限。
  
  资料来源:http://www.24drs.com/professional/list/content.asp?x_idno=6790&x_classno=0&x_chkdelpoint=Y
  

Preventing Unnecessary Appendectomies With CT, Ultrasound

By Troy Brown
Medscape Medical News

April 16, 2012 — Young children and girls older than 10 years appear to have fewer unnecessary appendectomies when diagnostic computerized tomography (CT) and/or ultrasound are used. These imaging techniques appear to have limited value in boys older than 5 years, however, according to a 5-year retrospective review of children with a diagnosis of appendicitis seen in the emergency departments (EDs) of 40 children's hospitals.

Richard G. Bachur, MD, chief of the Division of Emergency Medicine at Children's Hospital Boston, Massachusetts, and colleagues report their findings in an article published online April 16 in Pediatrics.

Dr. Bachur and colleagues determined the accuracy of CT and ultrasound for diagnosing appendicitis by calculating negative appendectomy rates (NARs) for each imaging method, stratified by sex and age (<5 years, 5 - 10 years, and >10 years of age). A negative appendectomy is the surgical removal of a normal appendix.

The researchers wanted to compare CT with ultrasound imaging because CT, which performs better, also exposes patients to ionizing radiation. Because radiation exposure is associated with an increased lifetime cancer risk, ultrasound is an attractive alternative, especially in children.

NARs were calculated by dividing the number of ED patients who underwent appendectomy without a final diagnosis of appendicitis by the total number of ED patients who underwent appendectomy.

The investigators calculated the associations between CT and ultrasound imaging and the outcome of negative appendectomy using linear regression analysis that used the hospital-level NAR as the dependent variable and the hospital-level imaging rate as the independent variable, weighted by the number of appendectomies done at each hospital. They performed this analysis on each age and sex subgroup, adjusting for patient volume at each institution.

From a total of 8,959,155 ED visits, 55,227 children were given a final diagnosis of appendicitis. Of those children, 35,335 (64.0%) had uncomplicated appendicitis, 13,166 (23.8%) had a perforated appendix, and 6.26 (12.2%) had a perforated appendix with abscess formation. Of the 52,290 patients who underwent an appendectomy, 96.4% received a final diagnosis of appendicitis, leaving a NAR of 3.6%.

Hospital-Level Analysis

CT rates were higher than ultrasound rates for each sex and age subgroup. In each subgroup, girls received more imaging than boys did, and children younger than 5 years were most likely to undergo both CT and ultrasound. The highest NARs were in children younger than 5 years and girls older than 10 years. There was a significant association between rate of CT and/or ultrasound use by individual institutions and the institutional NAR in all subgroups except children younger than 5 years. The CT rate alone was not associated with institutional NAR for any subgroup studied. The lowest NARs were found in boys older than 5 years, regardless of imaging method.

Patient-Level Analysis

Boys older than 5 years have lower NARs than boys younger than 5 years. Preappendectomy CT was significantly associated with lower NARs in boys younger than 5 years only, and ultrasound use was associated with higher NARs in boys younger than 5 years.

In girls younger than 5 years, CT was significantly associated with lower NARs, but there was no difference in NAR if ultrasound was used.

NARs were significantly higher in girls older than 10 years (5.5%) compared with boys (1.1%), independent of imaging (adjusted odds ratio, 5.2; 95% confidence interval, 4.4 - 6.1).

The Bottom Line

"The current study's findings extends to the clinical management by suggesting that age and gender must be incorporated into any evaluation algorithms," the authors write.

Because boys older than 5 years have the lowest NARs regardless of imaging method, the authors feel that CT and ultrasound imaging have limited value in this subgroup. "Of note, the paradoxically higher NAR for boys younger than 5 years who had an ultrasound (compared with those who did not have an ultrasound) might reflect an attempt to rely on ultrasound over CT when the diagnosis is especially difficult in this age group," the authors write.

"[T]he higher NAR for those girls older than 10 years likely stems from the presence of gynecologic conditions where secondary findings noted by imaging may mimic appendicitis," write the authors. "Despite this relatively high rate of negative appendectomy, the use of imaging among postpubertal girls is associated with the greatest absolute reduction in negative appendectomies as previously recognized," they write.

The authors conclude that CT and ultrasound reduce the higher NARs found in children younger than 5 years and girls older than 10 years, but appear to be of limited value in boys older than 5 years with suspected appendicitis and no other clinical issues.

The authors have disclosed no relevant financial relationships.

Pediatrics. Published online April 16, 2012.

    
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