Department of Emergency Medicine, Division of Emergency Ultrasound, Johns Hopkins University, Baltimore, Maryland 21287, USA.
Eur J Emerg Med. 2012 Oct;19(5):284-91. doi: 10.1097/MEJ.0b013e3283543cd3.
Emergency ultrasonography is a frequently used imaging tool in the bedside diagnosis of the acute abdomen. Classic indications include imaging for acute abdominal aneurysm, acute cholecystitis, hydronephrosis, and free intra-abdominal fluid in patients with trauma or suspected vascular or ectopic pregnancy rupture. Point-of-care sonographic imaging often emphasizes the diagnostic utility of fluid and edema, both as a significant finding and as a desirable adjunct for improved imaging. Conversely, the finding of sonographic intra-abdominal air is commonly 'tolerated' as a necessary evil that can foil image acquisition. This is in stark contrast to the accepted diagnostic utility of air in other imaging modalities for the acute abdomen, such as computed tomography and conventional radiography. Countering the bias against air as a deterrent for diagnostic ultrasound's accuracy are several published studies suggesting that abnormal air patterns can be used with high precision to diagnose pneumoperitoneum. These studies advocate that sonographic findings of abnormal air can be straightforward and can become crucial for increasing the diagnostic yield of bedside ultrasound of the acute abdomen. They suggest that practitioners should familiarize themselves with the findings and techniques to gain the experience required to make the diagnosis with confidence. This article will discuss four groups of abnormal air patterns found in the abdomen and the retroperitoneum and the respective scanning techniques, with a focus on the use of ultrasound for diagnosing pneumoperitoneum and a suggested scanning approach in the emergency setting.
急诊超声检查是一种常用于床边诊断急腹症的影像学工具。经典的适应证包括用于诊断急性腹主动脉瘤、急性胆囊炎、肾积水以及创伤或疑似血管或异位妊娠破裂患者的游离腹腔积液。床边即时超声成像通常强调了液体和水肿的诊断效用，这既是一种重要的发现，也是改善成像的理想辅助手段。相反，腹腔内出现超声气体会被普遍视为获取图像的障碍而“容忍”。这种情况与其他影像学方法在急腹症中对空气的公认诊断效用形成鲜明对比，如计算机断层扫描和常规 X 射线摄影。有几项已发表的研究表明，异常的气体会增加超声诊断的准确性，这为超声检查中对空气的偏见提供了有力的反驳。这些研究主张，可以使用高精度的异常气模式来诊断气腹，超声检查中异常气的发现可以是直接的，并且对于提高床边超声对急腹症的诊断效果至关重要。它们还建议从业者应熟悉这些发现和技术，积累经验，从而自信地做出诊断。本文将讨论在腹部和腹膜后发现的 4 组异常气模式，以及各自的扫描技术，重点介绍超声在诊断气腹中的应用，以及在紧急情况下的建议扫描方法。
