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（路透社健康版纽约12月20日电）新英格兰医学杂志新发表的一项随机对照研究显示：作为诊断呼吸机相关性肺炎的两种常用方法，支气管肺泡灌洗液定量培养和气管内抽吸物非定量培养对患者临床结局和抗生素使用的影响相似。

该研究共纳入740名疑诊呼吸机相关性肺炎的患者，分别来自于加拿大和美国的28个ICU。所有患者在培养结果出来之前均接受经验性抗感染治疗，而后开始针对性治疗。两组患者的28天死亡率无显著差异（分别为18.9%和18.4%），接受针对性治疗的比例（分别为74.2%和74.6%），未接受抗生素治疗的生存天数（分别为10.4和10.6），以及最大功能障碍评分和住院时间均相似。

该研究的设计者，Daren Heyland医生指出：“对于疑诊呼吸机相关性肺炎的患者，哪种手段是最佳的诊断方法目前尚无定论，本研究提示急进的方法不一定更好.只要临床医生对培养报告作出及时反映，便宜的非侵入性方法与昂贵的侵入性方法同样有效，而且可能会降低医疗费用。”

华盛顿大学的Marin H. Kollef医生评论说：“该研究的一个重要缺陷是排除了大量的可能存在定植菌或耐药菌感染的患者，结果显示支气管肺泡灌洗和气管内抽吸都有利于减少不必要的抗生素治疗。”

Two Tests Comparable for Diagnosing Ventilator-Associated Pneumonia

By Megan Rauscher

NEW YORK (Reuters Health) Dec 20 - For the diagnosis of ventilator-associated pneumonia, quantitative culture of bronchoalveolar lavage fluid and nonquantitative culture of endotracheal aspirate are associated with similar clinical outcomes and similar overall use of antibiotics, according to a randomized comparison of the two techniques.

The study, published in the December 21 issue of The New England Journal of Medicine, included 740 patients from 28 ICUs in Canada and the United States with suspected ventilator-associated pneumonia. All subjects were given empirical antibiotic therapy until culture results were available, at which point targeted therapy was initiated.

There was no significant difference in 28-day mortality, the primary outcome, between the bronchoalveolar lavage group and endotracheal-aspiration group (18.9% and 18.4%, respectively), researchers report.

The two groups also had similar rates of targeted therapy (74.2% and 74.6%), days alive without antibiotics (10.4 and 10.6), maximum organ dysfunction scores and length of ICU or hospital stay.

"Current data are conflicting on the optimal diagnostic approach in patients who have suspected ventilator-associated pneumonia," Dr. Daren Heyland from Kingston General Hospital and Queens University in Ontario and colleagues note in their report.

"There are different ways to diagnose and treat ventilator-associated pneumonia," Dr. Heyland, study leader, added in comments to Reuters Health. The current study shows that "more is not always better."

"In contrast to a study done in France, we demonstrated that the cheaper, less invasive method for making the diagnosis is just as good as more expensive and invasive techniques, provided that physicians diligently react to the culture results of whatever technique they use," Dr. Heyland explained.

"Since ventilator-associated pneumonia is the most common ICU-acquired infection, if the results of this study are applied to current practice, there is potential for considerable cost savings," Dr. Heyland concludes.

An "important" limitation of the study, notes Dr. Marin H. Kollef in a commentary, is the exclusion of a large number of screened patients with risk factors for colonization or infection with potentially antimicrobial-resistant bacteria. "Unfortunately, these exclusions probably represent the majority of patients undergoing real-time evaluation for suspected ventilator-associated pneumonia," Dr. Kollef from Washington University in St. Louis points out.

And while the study found that bronchoalveolar lavage did not influence in-hospital mortality or length of ICU stay compared with endotracheal aspiration, "the main potential effect of bronchoalveolar lavage is to permit the de-escalation or cessation of unnecessary antimicrobial therapy."

When applied properly, bronchoalveolar lavage and endotracheal aspiration are both "tools that can facilitate de-escalation," Dr. Kollef concludes.

N Engl J Med 2006;355:2619-2630,2691-2693.

http://www.medscape.com/viewarticle/549725

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