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Compression Ultrasonography of the Lower Extremity With Portable Vascular Ultrasonography Can Accurately Detect Deep Venous Thrombosis in the Emergency Department
在急诊科使用便携式血管超声波对下肢进行加压超声检查可准确检测深静脉血栓形成

Jonathan G. Crisp, MD, MS, Luis M. Lovato, MD, Timothy B. Jang, MDFrom the Department of Emergency Medicine, University of California Los Angeles-Olive View Medical Center, Los Angeles, CA (Crisp, Lovato, Jang); the
来自加利福尼亚州洛杉矶加利福尼亚大学洛杉矶分校-橄榄景医疗中心急诊医学系（Crisp、Lovato、Jang）；来自加利福尼亚州洛杉矶加利福尼亚大学洛杉矶分校-橄榄景医疗中心急诊医学系（Crisp、Lovato、JangDivision of Emergency Medicine, Greater Los Angeles Veterans Healthcare Administration, Los Angeles, CA (Crisp); and the Department of Emergency
加利福尼亚州洛杉矶市大洛杉矶退伍军人医疗管理局急诊医学部（Crisp）；以及急诊部Medicine, Harbor-UCLA Medical Center, Torrance, CA (Jang).

Abstract

Study objective: Compression ultrasonography of the lower extremity is an established method of detecting proximal lower extremity deep venous thrombosis when performed by a certified operator in a vascular laboratory. Our objective is to determine the sensitivity and specificity of bedside 2-point compression ultrasonography performed in the emergency department (ED) with portable vascular ultrasonography for the detection of proximal lower extremity deep venous thrombosis. We did this by directly comparing emergency physician-performed ultrasonography to lower extremity duplex ultrasonography performed by the Department of Radiology.
研究目的下肢加压超声造影是一种检测下肢近端深静脉血栓的成熟方法，由血管实验室的认证操作员执行。我们的目的是确定在急诊科（ED）进行的床旁两点式加压超声检查与便携式血管超声检查在检测下肢近端深静脉血栓方面的敏感性和特异性。为此，我们将急诊科医生进行的超声波检查与放射科进行的下肢双相超声波检查进行了直接比较。

Methods: This was a prospective, cross-sectional study and diagnostic test assessment of a convenience sample of ED patients with a suspected lower extremity deep venous thrombosis, conducted at a single-center, urban, academic ED. All physicians had a 10-minute training session before enrolling patients. ED compression ultrasonography occurred before Department of Radiology ultrasonography and involved identification of 2 specific points: the common femoral and popliteal vessels, with subsequent compression of the common femoral and popliteal veins. The study result was considered positive for proximal lower extremity deep venous thrombosis if either vein was incompressible or a thrombus was visualized. Sensitivity and specificity were calculated with the final radiologist interpretation of the Department of Radiology ultrasonography as the criterion standard.
方法：这是一项前瞻性、横断面研究，对疑似下肢深静脉血栓形成的急诊科患者进行诊断测试评估。所有医生在招募患者之前都接受了 10 分钟的培训。急诊室压迫超声波检查在放射科超声波检查之前进行，包括确定两个特定点：股总血管和腘血管，随后压迫股总静脉和腘静脉。如果任一静脉无法压迫或发现血栓，则认为下肢近端深静脉血栓形成的研究结果呈阳性。敏感性和特异性的计算以放射科超声波检查的最终放射科医生的解释为标准。

Results: A total of 47 physicians performed 199 2-point compression ultrasonographic examinations in the ED. Median number of examinations per physician was 2 (range 1 to 29 examinations; interquartile range 1 to 5 examinations). There were 45 proximal lower extremity deep venous thromboses observed on Department of Radiology evaluation, all correctly identified by ED 2-point compression ultrasonography. The 153 patients without proximal lower extremity deep venous thrombosis all had a negative ED compression ultrasonographic result. One patient with a negative Department of Radiology ultrasonographic result was found to have decreased compression of the popliteal vein on ED compression ultrasonography, giving a single false-positive result, yet repeated ultrasonography by the Department of Radiology 1 week later showed a popliteal deep venous thrombosis. The sensitivity and specificity of ED 2-point compression ultrasonography for deep venous thrombosis were 100% ( confidence interval to ) and ( confidence interval to ), respectively.
结果：共有 47 名医生在急诊室进行了 199 次两点按压超声波检查。每位医生检查次数的中位数为 2 次（1 至 29 次不等；四分位数间距为 1 至 5 次）。在放射科的评估中，共观察到 45 例下肢近端深静脉血栓，均通过急诊室 2 点加压超声波检查正确识别。153 名未发现下肢近端深静脉血栓的患者的急诊科加压超声检查结果均为阴性。有一名放射科超声检查结果为阴性的患者在急诊科加压超声检查中发现腘静脉受压程度降低，因此出现了一次假阳性结果，但一周后放射科再次进行超声检查时却发现腘静脉深静脉血栓形成。急诊室两点加压超声造影对深静脉血栓形成的敏感性和特异性分别为100% ( 置信区间 至 ) 和 ( 置信区间 至 )。

Conclusion: Emergency physician-performed 2-point compression ultrasonography of the lower extremity with a portable vascular ultrasonographic machine, conducted in the ED by this physician group and in this patient sample, accurately identified the presence and absence of proximal lower extremity deep venous thrombosis. [Ann Emerg Med. 2010;56:601-610.]
结论：由急诊科医生使用便携式血管超声波机对下肢进行两点按压超声波检查，在急诊室由该医生小组在该患者样本中进行，可准确识别是否存在下肢近端深静脉血栓。[Ann Emerg Med.］

Please see page 602 for the Editor's Capsule Summary of this article.

Provide feedback on this article at the journal's Web site, www.annemergmed.com.
0196-0644/$-see front matter
Copyright © 2010 by the American College of Emergency Physicians
doi:10.1016/j.annemergmed.2010.07.010

SEE EDITORIAL, P. 611.

INTRODUCTION

Rapid and accurate detection of deep venous thrombosis and the prevention of pulmonary embolism is a critical aspect of emergency medicine worldwide. Approximately 2 million patients are diagnosed with a deep venous thrombosis annually in the United States, with approximately 600,000 hospitalizations and another 200,000 deaths resulting from pulmonary embolism. Because none of the available imaging modalities have ideal test characteristics, the diagnosis of deep venous thrombosis remains challenging. Contrast venography exposes the patient to radiation and intravenous contrast material, has special technical
快速准确地检测深静脉血栓和预防肺栓塞是全球急诊医学的一个重要方面。在美国，每年约有 200 万名患者被诊断为深静脉血栓， ，约有 60 万人住院治疗，另有 20 万人死于肺栓塞。 由于现有的成像模式都不具备理想的检测特性，因此深静脉血栓的诊断仍然具有挑战性。 静脉造影术会使患者暴露于辐射和静脉造影剂中，具有特殊的技术要求。

Editor's Capsule Summary

What is already known on this topic

Radiology department ultrasonography is commonly used to detect lower extremity deep venous thrombosis. Studies of emergency physician-performed ultrasonography have shown mixed results.
放射科超声波检查常用于检测下肢深静脉血栓。对急诊医生进行超声波检查的研究结果不一。

What question this study addressed

Can emergency physicians who received 10 minutes of training use a low-resolution portable ultrasonographic machine and a 2-point (at common femoral and popliteal vessels only) compression technique to accurately diagnose proximal lower extremity deep venous thrombosis?
接受过 10 分钟培训的急诊医生能否使用低分辨率便携式超声波成像仪和两点（仅股总动脉和腘动脉）压迫技术准确诊断下肢近端深静脉血栓？

What this study adds to our knowledge

Forty-seven physicians examined 199 patients, achieving a sensitivity of and a specificity of , as judged by the official radiology ultrasonography.
47 名医生对 199 名患者进行了检查，根据官方放射学超声波检查的判断，灵敏度为 ，特异性为 。

How this might change clinical practice

Novice physicians using a simplified technique achieved remarkable accuracy. These findings, if confirmed, could result in practice changes that would expedite the emergency department care of patients with suspected deep venous thrombosis.
使用简化技术的新手医生取得了显著的准确性。这些发现如果得到证实，将有助于改变急诊科对疑似深静脉血栓患者的治疗。
requirements that limit its availability, and has associated morbidity. For these reasons, duplex ultrasonography (compression ultrasonography, as well as color and flow Doppler ultrasonography) of the lower extremity, performed by a certified technician and interpreted by a radiologist, has emerged as an effective first-line method of detecting deep venous thrombosis, with a reported sensitivity of to and a specificity of to . 5,6 It has replaced other diagnostic imaging methods in common practice and many now consider duplex ultrasonography of the lower extremity to be the standard of care in diagnosing proximal lower extremity deep venous thrombosis.
但这种方法的要求较高，限制了其可用性，而且还伴有相关的发病率。 由于这些原因，由经认证的技术人员进行并由放射科医生判读的下肢双相超声造影（压缩超声造影以及彩色和血流多普勒超声造影）已成为检测深静脉血栓的有效一线方法，据报道其灵敏度为 至 ，特异性为 至 。5,6在常见的临床实践中，它已取代了其他影像诊断方法，现在许多人认为下肢双相超声波检查是诊断下肢近端深静脉血栓的标准方法。
Despite these advances in ultrasonographic research, a standard protocol for ultrasonographic evaluation of lower extremity deep venous thrombosis is not universally accepted. Whereas some hospital radiology laboratories image the proximal lower extremity only, others perform wholeleg duplex imaging of the entire venous system. Although the former investigates the proximal lower extremity only, the whole-leg approach is able to detect isolated calf deep venous thrombosis, in addition to proximal lower extremity deep venous thrombosis. Although some consider whole-leg ultrasonography superior because of its ability to diagnose calf and proximal lower extremity deep venous thrombosis, the evidence for this is based on the thought that detecting isolated calf deep venous thrombosis is clinically important. recent study randomized patients to radiologist-performed serial 2-point compression ultrasonography plus serum D-dimer or whole-leg color duplex ultrasonography and found the 2 diagnostic strategies to be equivalent for the management of symptomatic outpatients with suspected lower extremity deep venous thrombosis. The long-term outcome was similar, even though the 2-point compression group missed several calf deep venous thromboses. However, the ability to obtain a radiologistperformed (or technician-performed and radiologist interpreted) duplex ultrasonography of the lower extremity in the emergency department (ED) can be difficult after hours or on weekends because some hospitals do not have duplex ultrasonography available to the ED at all times.
尽管超声研究取得了这些进展，但下肢深静脉血栓超声评估的标准方案并未得到普遍认可。 一些医院的放射实验室只对下肢近端进行成像，而另一些则对整个静脉系统进行全腿双频成像。 虽然前者只检查下肢近端，但全腿法除了能检测下肢近端深静脉血栓外，还能检测孤立的小腿深静脉血栓。尽管有些人认为全腿超声检查更优越，因为它能诊断小腿和下肢近端深静脉血栓，但其证据是基于检测孤立的小腿深静脉血栓在临床上非常重要这一观点。 最近的一项研究将患者随机分配到放射科医生实施的连续两点按压超声检查加血清 D-二聚体或全腿彩色双工超声检查，结果发现这两种诊断策略在处理疑似下肢深静脉血栓的无症状门诊患者方面效果相当。 尽管两点按压组漏诊了几例小腿深静脉血栓，但长期疗效相似。然而，在下班后或周末，急诊科（ED）很难获得由放射科医生操作（或由技术人员操作、放射科医生解释）的下肢双相超声波检查，因为有些医院的急诊科并非随时都能使用双相超声波检查。
In 2006, the American College of Emergency Physicians (ACEP) released a clinical compendium outlining the use of emergency ultrasonography, in which bedside compression ultrasonography was described as an appropriate method for evaluating lower extremity deep venous thrombosis in the ED. ACEP published an emergency ultrasonography policy statement in 2009 that listed deep venous thrombosis as one of the 11 core emergency ultrasonography applications, yet deep venous thrombosis was identified as a less established application that was only recently adopted because of utility and research. Furthermore, the emergency medicine community has not universally accepted a standard protocol for ED ultrasonographic evaluation of lower extremity deep venous thrombosis. Whole-leg ED duplex ultrasonography of the entire lower extremity venous system by emergency physicians trained with a 30-hour ultrasonographic course had a sensitivity and specificity potentially high enough to be used as a standalone test for ED patients ( ), but this requires a significant ED time commitment (greater than 13 minutes) and a higher level of training than general ED practice. recent study using a large heterogeneous group of emergency clinicians with various levels of ultrasonographic experience demonstrated that ED-performed ultrasonography with a 3-point compression technique was sensitive ( confidence interval [CI] to ) and specific ( CI to ) compared with radiology-performed ultrasonography, raising concern about the widespread use of ED ultrasonography for deep venous thrombosis.
2006 年，美国急诊医师学会 (ACEP) 发布了一份临床简编，概述了急诊超声造影的应用，其中将床旁加压超声造影描述为在急诊室评估下肢深静脉血栓的适当方法。 ACEP 于 2009 年发布了一份急诊超声波检查政策声明，将深静脉血栓列为 11 项核心急诊超声波检查应用之一，但深静脉血栓检查被认为是一项不太成熟的应用，直到最近才因为实用性和研究而被采用。 此外，急诊医学界尚未普遍接受急诊室超声评估下肢深静脉血栓的标准方案。 由接受过 30 小时超声课程培训的急诊医生对整个下肢静脉系统进行全腿 ED 双相超声检查，其灵敏度和特异性可能很高，足以作为 ED 患者的独立检查 ( )，但这需要投入大量的 ED 时间（超过 13 分钟），并且需要比普通 ED 实践更高水平的培训。 最近的一项研究使用了一大批具有不同超声经验的急诊临床医生，结果表明，与放射科进行的超声波检查相比，急诊室进行的三点按压超声波检查的灵敏度为 ( 置信区间 [CI] to ) ，特异性为 ( CI to ) ，这引起了人们对广泛使用急诊室超声波检查深静脉血栓的担忧。
Although the methods used to detect deep venous thrombosis range from 2-point compression of the femoral and popliteal vessels to whole-leg duplex imaging of the entire venous system, numerous studies have used different compression sites along the femoral and popliteal vessels, with reported sensitivities ranging from to and specificities of to This research was also performed in various settings, such as radiology laboratories, EDs, and inpatient wards, and by various operators
尽管用于检测深静脉血栓的方法从两点压迫股血管和腘血管到整个静脉系统的全腿双相成像不等，但许多研究都使用了股血管和腘血管的不同压迫部位，据报道，灵敏度从 到 ，特异性从 到 。这项研究也是在不同的环境下进行的，如放射实验室、急诊室和住院病房，并由不同的操作人员进行。
(radiologists, physicians, technicians, midlevel providers). Several studies showed that investigation of the proximal lower extremity veins by 2-point compression applied to the common femoral vein at the groin and the popliteal vein at the popliteal fossa can be effective in identifying proximal lower extremity deep venous thrombosis. Furthermore, this method is thought to be adequate and reproducible when performed with almost any year and model of ultrasonographic machine, despite the resolution or
(放射科医生、内科医生、技术人员、中级医疗人员）。多项研究表明，通过对腹股沟处的股总静脉和腘窝处的腘静脉进行两点压迫来检查下肢近端静脉，可有效识别下肢近端深静脉血栓。 此外，这种方法被认为在使用几乎所有年份和型号的超声波机时都是适当和可重复的，尽管其分辨率或
frequency of the vascular probe.
Portable vascular ultrasonographic machines are used in many hospitals for vascular access and are smaller than conventional machines. They are lightweight, battery powered, and relatively inexpensive and became popular as a result of emphasis on ultrasonographically guided central line placement for patient safety core measures.
许多医院都使用便携式血管超声成像仪进行血管通路检查，这种仪器比传统仪器更小巧。 它们重量轻、电池供电、价格相对低廉，由于强调以超声引导中心静脉置管作为患者安全的核心措施，因此大受欢迎。
This study sought to assess whether bedside 2-point compression ultrasonography of the lower extremity at the common femoral and popliteal vessels only, performed by physicians in the ED with a portable vascular ultrasonographic machine, could detect the presence or absence of proximal lower extremity deep venous thrombosis with acceptable test characteristics.
本研究旨在评估由急诊室医生使用便携式血管超声机对下肢股总血管和腘血管进行床旁两点加压超声造影是否能检测出下肢近端深静脉血栓的存在与否，且检测特征是否可接受。

MATERIALS AND METHODS

Study Design

This was an institutional review board-approved, prospective, cross-sectional study and diagnostic test assessment of a convenience sample of ED patients with a suspected lower extremity deep venous thrombosis. All patients enrolled in the study presented to the ED with a suspected lower extremity deep venous thrombosis and underwent 2-point compression ultrasonography with portable vascular ultrasonography in the ED before formal Department of Radiology evaluation (Figure 1).
这是一项经机构审查委员会批准的前瞻性横断面研究，对急诊科疑似下肢深静脉血栓患者进行诊断测试评估。所有参加研究的患者都是因怀疑下肢深静脉血栓形成而到急诊科就诊的，在放射科进行正式评估之前，他们都在急诊科接受了便携式血管超声仪的两点压迫超声检查（图 1）。

Setting

This study was performed at a single-center, urban, university-affiliated public hospital with an emergency medicine residency program and an annual ED census of 60,000.
这项研究是在一家单中心、城市、大学附属公立医院进行的，该医院设有急诊医学住院医师培训项目，急诊室年接待量为 60,000 人。

Selection of Participants

Eligible patients were aged 18 years or older, suspected of having a lower extremity deep venous thrombosis, and undergoing Department of Radiology ultrasonography of the lower extremity. There was no distinction made between patients suspected of having a proximal lower extremity deep venous thrombosis or an isolated calf deep venous thrombosis for enrollment purposes. Any patient with a suspected lower extremity deep venous thrombosis was eligible. Patients with a known deep venous thrombosis, a previous deep venous thrombosis in the past 6 months, or a recent duplex ultrasonography (within the past month) were excluded from the study. There were no exclusions made according to sex,
符合条件的患者年龄在 18 岁或以上，怀疑患有下肢深静脉血栓，并正在接受放射科的下肢超声波检查。在注册时，不区分疑似下肢近端深静脉血栓或孤立的小腿深静脉血栓患者。任何疑似下肢深静脉血栓患者均符合条件。已知有深静脉血栓、过去 6 个月内曾有过深静脉血栓或最近（过去一个月内）做过双相超声波检查的患者不在研究范围内。 没有根据性别进行排除、
Figure 1. Flow diagram of study design and endpoints. DVT, Deep venous thrombosis; CUS, compression ultrasonography.
race, or weight. Our convenience sample was defined as those enrolled at the convenience of the treating physician. Enrolling physicians were given a gift card to a local outdoor equipment store for each completed enrollment form and were encouraged to enroll every patient that qualified for and consented to the study. Physician subjects were board-certified emergency medicine attending physicians and postgraduate residents working in the ED: years 2 to 4 emergency medicine residents, rotating years 2 to 3 internal medicine residents, years 1 to 5 combined emergency medicine/internal medicine residents, and year 2 family medicine residents.
种族或体重。我们的方便样本是指那些在主治医生方便时加入的样本。注册医生每填写一份注册表，就会获得一张当地户外用品商店的 礼品卡，我们鼓励每位符合条件并同意参加研究的患者都注册。受试医生是在急诊室工作的经委员会认证的急诊科主治医师和研究生住院医师：2 至 4 年级的急诊科住院医师、2 至 3 年级的内科住院医师、1 至 5 年级的急诊科/内科联合住院医师以及 2 年级的家庭医学住院医师。

Interventions

Before enrolling patients, all participating physicians had a 10-minute bedside training session. Previous data have shown that emergency medicine residents can perform a detailed multiple-point proximal lower extremity deep venous thrombosis compression ultrasonographic examination in less than 12 minutes and a 2-point compression examination in less than 4 minutes. Because our study involved 2-point compression ultrasonography of only the common femoral and popliteal vessels, the training session did not require more than 10 minutes. A uniform training session was agreed on by the 3 study investigators and was given to all levels of physicians
在收治患者之前，所有参与医生都接受了 10 分钟的床边培训。之前的数据显示，急诊科住院医生可以在 12 分钟内完成详细的多点下肢近端深静脉血栓压迫超声波检查 ，在 4 分钟内完成 2 点压迫检查。 由于我们的研究只涉及股总血管和腘血管的两点压迫超声检查，因此培训课程不需要超过 10 分钟。3 位研究人员商定了统一的培训课程，并向所有级别的医生提供培训
involved in this study. Only the 3 study investigators conducted the training sessions, which took place during any shift worked by one of the 3 investigators during the enrollment period. Each training session involved familiarization with study criteria and verbal instruction on how to identify normal anatomy, incompressibility, and thrombus. Instruction also included bedside use of the portable vascular ultrasonographic machine, with identification of the popliteal vein and common femoral vein on a normal volunteer patient, chosen at random by the instructing study investigator. The enrolling physicians had to demonstrate their ability to find the femoral and popliteal veins, measure their compressibility, and describe how both an incompressible vein and a thrombus would appear on ultrasonography. This was done before enrolling patients and before the conclusion of the training session. If physicians were not sure whether they had identified the correct vein, or if they could not tell whether a vein was compressible or whether a thrombus was present, they were instructed to select the "other" option on the data sheet and indicate which vessel gave them problems. Common mistakes, such as having the incorrect depth setting or positioning the probe incorrectly, were reviewed during the training session. Physicians were free to enroll patients after completion of the training session. A study investigator was not required to be present during enrollment by a trained physician after completion of a training session.
参与这项研究。只有 3 位研究人员进行了培训，培训时间为 3 位研究人员中任何一位在注册期间的轮班时间。每次培训都包括熟悉研究标准以及如何识别正常解剖结构、不可压缩性和血栓的口头指导。培训内容还包括在床边使用便携式血管超声成像仪，由指导研究人员随机选择一名正常志愿患者，对其腘静脉和股总静脉进行识别。报名的医生必须证明自己有能力找到股静脉和腘静脉，测量它们的可压缩性，并描述不可压缩的静脉和血栓在超声波成像中的表现。这些都是在病人入院前和培训课程结束前完成的。如果医生不确定自己是否识别出了正确的静脉，或无法判断静脉是否可压缩或是否存在血栓，他们会被指示在数据表上选择 "其他 "选项，并指出哪条血管给他们带来了问题。在培训过程中，医生们还复习了一些常见错误，例如深度设置不正确或探头定位不正确。培训课程结束后，医生可以自由地为患者注册。培训课程结束后，接受过培训的医生在为患者注册时，研究调查人员无需在场。

Methods of Measurement

Physician subjects performed compression ultrasonography with the Bard Site-Rite IV portable vascular ultrasonography (Salt Lake City, UT), using the standard 7.5-MHz linear probe supplied with the machine. This probe allows a depth of 2 or 4 , with limited contrast and gain capabilities. Compression ultrasonographic evaluation involved identification of only the common femoral vessels at the level of the groin and the popliteal vessels in the popliteal fossa, with subsequent compression of the common femoral and popliteal veins. The minimum number of times that each vessel would be compressed was one single attempt, and the maximum number of compressions at each site was not specified. After the patient consented to enrollment, enrolling physicians followed a study protocol that first involved finding the common femoral vessels and documenting the compressibility of the femoral vein or presence of thrombus on a standardized data sheet. Next, the popliteal vessels were identified, and the compressibility or presence of thrombus was documented on the same standardized data sheet. If the physician was unable to identify one or both of the vessels, or if the results of compression or thrombus were indeterminate, this was documented by an "other" option on the data sheet.
受试医生使用 Bard Site-Rite IV 便携式血管超声诊断仪（美国犹他州盐湖城），使用该仪器随附的标准 7.5 兆赫线性探头进行压缩超声检查。该探头的深度为 2 或 4 ，对比度和增益能力有限。压迫超声波评估只涉及识别腹股沟处的股总血管和腘窝处的腘血管，随后对股总静脉和腘静脉进行压迫。每条血管的最少压迫次数为一次，每个部位的最多压迫次数未作规定。在患者同意入选后，入选医生按照研究方案进行操作，首先要找到股总血管，并在标准数据表上记录股静脉的可压缩性或是否存在血栓。然后，确定腘血管，并在同一张标准化数据表上记录其可压缩性或是否存在血栓。如果医生无法确定其中一根或两根血管，或者压迫或血栓结果不确定，则在数据表上记录 "其他 "选项。
The ED compression ultrasonographic result was considered positive for proximal lower extremity deep venous thrombosis if either vein was not compressible or a thrombus was visualized. All ED compression ultrasonographic measurements were followed by immediate (within 3 hours) duplex ultrasonographic evaluation by the Department of Radiology to assess for proximal lower extremity deep venous thrombosis, performed in the ultrasonographic suite. All Department of Radiology duplex ultrasonography was performed with either a Phillips IU 22 (Bothell, WA) with an L9-3 linear array probe or a Phillips HD 5000 ATL with an L7-4 linear array probe. According to our Department of Radiology protocol, only the proximal lower extremity venous system was evaluated. The calf veins distal to the popliteal veins were not imaged. Still images were recorded 24 hours a day, 7 days a week, by one of 10 fulltime ultrasonographers, 5 of whom were credentialed as registered diagnostic medical sonographers. Images were electronically transmitted to one of 5 attending board-certified staff radiologists from the Division of Ultrasonography and Mammography who routinely read ultrasonographic images at our hospital. The Department of Radiology ultrasonographic technicians and attending radiologists were blinded to all ED compression ultrasonographic results. The name and medical record number of each patient were used by study investigators or research assistants trained in data abstraction to archive the final dictated interpretation of each Department of Radiologyperformed duplex study.
如果任一静脉无法压缩或发现血栓，则 ED 加压超声波检查结果被视为下肢近端深静脉血栓阳性。所有急诊室加压超声波测量结果均由放射科立即（3 小时内）进行双相超声波评估，以评估是否存在下肢近端深静脉血栓，评估在超声波室进行。放射科的所有双相超声检查均使用配备 L9-3 线性阵列探头的 Phillips IU 22 (Bothell, WA) 或配备 L7-4 线性阵列探头的 Phillips HD 5000 ATL 进行。根据我们放射科的规程，只对下肢近端静脉系统进行评估。小腿静脉远端至腘静脉未进行成像。静态图像由 10 名全职超声技师（其中 5 名具有注册医学超声诊断技师资格）中的一名进行每周 7 天、每天 24 小时的记录。图像以电子方式传送给本医院超声波和乳腺 X 线照相术部的 5 位主治医师之一，这些医师均持有注册医师资格，可在本医院例行阅读超声波图像。放射科超声波技师和放射科主治医生对所有 ED 压缩超声波检查结果均为盲法。每位患者的姓名和病历号由研究调查人员或接受过数据摘要培训的研究助理用于归档放射科进行的每项双相检查的最终口述解释。

Outcome Measures

The primary outcome measure was the identification of a proximal lower extremity deep venous thrombosis through the use of bedside ED 2-point compression ultrasonography. The final attending radiologist interpretation of the Department of Radiology-performed study was considered the criterion standard for study purposes. Secondary outcome measures were the characteristics of the deep venous thrombosis observed on ED compression ultrasonography: compressibility, thrombus visualization, and location of deep venous thrombosis.
主要结果指标是通过使用床旁急诊室两点加压超声波检查发现下肢近端深静脉血栓。放射科主治医生对放射科所做研究的最终解释被视为研究目的的标准。次要结果指标是急诊室加压超声造影观察到的深静脉血栓的特征：可压缩性、血栓可视性和深静脉血栓的位置。

Primary Data Analysis

Data collected for this study were maintained in a Microsoft Excel (Version 11 and 12.0, Microsoft, Redmond, WA) worksheet, with subsequent analysis using Stata (Version 10, Statacorp, College Station, TX) and VassarStats. According to a 2005 quality assurance project conducted as part of the ultrasonography education program for the emergency medicine residency at our hospital, of patients sent for lower extremity duplex ultrasonography from the ED were found to have a proximal lower extremity deep venous thrombosis. A priori power calculation estimated that 186 patients were needed to detect a minimum sensitivity for ED compression ultrasonography such that the lower-bound limit of the would be greater than .
本研究收集的数据保存在 Microsoft Excel（版本 11 和 12.0，Microsoft，Redmond，WA）工作表中，随后使用 Stata （版本 10，Statacorp，College Station，Texas）和 VassarStats 进行分析。 根据本医院 2005 年作为急诊医学住院医生超声造影教育项目的一部分而开展的质量保证项目，在急诊室送去进行下肢双相超声造影检查的患者中， 发现有下肢近端深静脉血栓。根据先验功率计算估计，需要186名患者才能检测出急诊室压迫超声检查的最低灵敏度，从而使 的下限大于 。

RESULTS

From June 2006 through July 2007, 47 physicians enrolled 188 patients, resulting in 200 total examinations. Twelve patients were enrolled separately for bilateral lower extremity ultrasonography. The total number of patients who had a formal duplex Department of Radiology study ordered from the
从 2006 年 6 月到 2007 年 7 月，47 名医生为 188 名患者进行了登记，共进行了 200 次检查。有 12 名患者分别接受了双侧下肢超声波检查。在放射科进行正式双相超声检查的患者总人数如下
Table 1. Sensitivity and specificity of ED two-point compression ultrasonography, using Department of Radiology ultrasonography as the gold standard.
表 1.以放射科超声波检查为金标准的 ED 两点压迫超声波检查的敏感性和特异性。
ED
Ultrasonography
Category
Positive DOR
Ultrasonographic
Results
Negative DOR
Ultrasonographic
Results
Positive ED
compression
ultrasonography
45 1
Negative ED
compression
ultrasonography
Sensitivity, %
Specificity, %
100 (95% CI 92-100) 153
DOR, Department of Radiology. 99.4 (95% Cl 96-100)
ED to assess for lower extremity deep venous thrombosis during this time was 248,10 of which were cancelled before the study was performed by the ordering clinician or ED clerk for unknown reasons (ordered in error, wrong patient, change of mind, etc). This accounted for 238 total duplex ultrasonography examinations (unilateral and bilateral) ordered by the ED and performed by the Department of Radiology. Our convenience sample enrolled 188 of the 238 total patients evaluated for the presence of a lower extremity deep venous thrombosis during the enrollment period.
在此期间，急诊科为评估下肢深静脉血栓而进行的双相超声波检查有 248 次，其中 10 次在检查开始前被下单的临床医生或急诊科办事员取消，原因不明（下单错误、找错病人、改变主意等）。这样，由急诊室下达指令并由放射科实施的双工超声检查（单侧和双侧）总数为 238 例。在 238 位接受评估的患者中，有 188 位在登记期间发现了下肢深静脉血栓。
Of the 200 examinations performed by the physician subjects in the ED and enrolled in the study, 199 had complete data and were included in the final data analysis. One examination was excluded because the patient name and medical record number were not recorded. No other examinations were excluded from those collected, and none of the enrolled examinations or the excluded examination was found to have indeterminate results.
在由急诊室医生受试者进行的 200 次检查中，有 199 次检查的数据完整，并纳入了最终数据分析。有一项检查因没有记录患者姓名和病历号而被排除在外。所收集到的数据中没有排除其他检查，而且没有发现登记的检查或排除的检查有不确定的结果。
Bedside 2-point compression ultrasonography of the lower extremity, performed by physicians in the ED with a portable vascular ultrasonographic machine for the evaluation of proximal lower extremity deep venous thrombosis, had a sensitivity of ( CI to ) and a specificity of ( CI to ) (Table 1). There were 45 deep venous thromboses observed on Department of Radiology evaluation, and all were correctly identified by ED 2-point compression ultrasonography (Table 2). There were 154 patients without a deep venous thrombosis on Department of Radiology ultrasonography, all of whom had a negative ED 2point compression ultrasonography result except for one, in which compression ultrasonography by the enrolling emergency physician showed decreased compressibility of the popliteal vein, suggesting the presence of a deep venous thrombosis by our study criteria. In this subject, the decreased popliteal compression was also noted in the attending radiologist reading of the Department of Radiology study, but a definite deep venous thrombosis was not diagnosed and the study result was dictated as negative by the attending radiologist. Repeated duplex evaluation result by the Department of Radiology at 1 week was positive for a popliteal deep venous thrombosis. This was considered a false-positive result according to the study protocol, and there were no false-negative results. Deep venous thrombosis characteristics are summarized in Table 3.
下肢床旁两点加压超声检查由急诊科医生使用便携式血管超声检查仪进行，用于评估下肢近端深静脉血栓形成，其敏感性为 ( CI to ) ，特异性为 ( CI to ) （表 1）。在放射科的评估中，共观察到 45 例深静脉血栓，所有患者都能通过 ED 2 点压迫超声波检查正确识别（表 2）。有 154 名患者在放射科超声波检查中未发现深静脉血栓，他们的急诊室 2 点加压超声波检查结果均为阴性，只有一人例外，其急诊医生的加压超声波检查显示腘静脉的可压缩性降低，这表明根据我们的研究标准存在深静脉血栓。在该患者中，放射科主治医生在阅读放射科的研究报告时也发现腘静脉压缩性下降，但并未确诊为深静脉血栓，放射科主治医生将研究结果判定为阴性。1 周后，放射科再次进行双光谱评估，结果显示腘深静脉血栓呈阳性。根据研究方案，这是一个假阳性结果，没有假阴性结果。表 3 总结了深静脉血栓的特征。
If the results of ED compression ultrasonography are compared directly with Department of Radiology duplex ultrasonography for equivalence, Cohen's coefficient is 0.99 ( CI 0.958 to 1 ).
如果将 ED 压迫超声波检查结果与放射科双相超声波检查结果直接进行等效比较，Cohen's 系数为 0.99 ( CI 0.958 至 1 )。
A histogram displaying the results of the 199 examinations by 47 operators is shown (Figure 2). The median number of patients enrolled per physician was 2 (range 1 to 29 patients; interquartile range 1 to 5 patients). Of the enrolling physician subjects, there were 2 attending physicians and 45 residents. One attending physician had completed an ultrasonographic fellowship and previously performed more than 1,000 ultrasonographic examinations, including 50 previous compression ultrasonographic examinations for deep venous thrombosis. This attending physician was also a study investigator and performed 29 of the 199 examinations. The other attending physician previously performed 2 compression ultrasonographic examinations for deep venous thrombosis, and 1 resident had previously performed 2 as well. The remaining 44 enrolling physicians had not performed compression ultrasonography for deep venous thrombosis before this study. The average experience level of the enrolling emergency physicians (excluding the ultrasonographically trained attending physician) was 14.5 previous ultrasonographic examinations (median 5 examinations; mode 5 examinations; range 2 to 98 examinations), including all indications of ED ultrasonography.
图 2 显示了 47 名操作员 199 次检查结果的直方图。每位医生登记的患者人数中位数为 2 人（范围为 1 至 29 人；四分位数范围为 1 至 5 人）。在登记的医生受试者中，有 2 名主治医生和 45 名住院医生。其中一名主治医师已完成超声研究，并曾进行过 1000 多次超声检查，包括 50 次针对深静脉血栓的压缩超声检查。这位主治医师也是研究调查员，并进行了 199 次检查中的 29 次。另一名主治医师曾为深静脉血栓进行过 2 次加压超声波检查，一名住院医师也曾进行过 2 次检查。其余 44 名参加研究的医生在本研究之前没有进行过针对深静脉血栓的加压超声检查。参加研究的急诊医生（不包括接受过超声波检查培训的主治医生）的平均超声波检查经验为 14.5 次（中位数 5 次；模数 5 次；范围 2 到 98 次），包括急诊室超声波检查的所有适应症。

LIMITATIONS

This study has limitations that are important to consider when the results are interpreted. The first limitation is the use of a convenience sample of patients and enrolling physicians rather than studying all consecutive patients sent for a Department of Radiology evaluation. It was not feasible for us to enroll consecutive patients because of the time constraints of maintaining adequate patient flow in a busy ED. This sampling method therefore could involve a patient selection bias in which certain patients (ie, difficult or equivocal patients) may not have been enrolled, which if present could have led to an overestimation in the sensitivity and specificity of ED 2-point compression ultrasonography. We did not collect data on patient demographics, such as body mass index, sex, or ethnicity, which may affect the comparison of patients enrolled in our study to other populations. Our convenience sample did enroll 188 of the 238 total patients who had a formal Department of Radiology duplex ultrasonographic examination, indicating that we captured of the total patients evaluated for lower extremity deep venous thrombosis in the ED during the study period.
这项研究存在一些局限性，在解释结果时必须加以考虑。第一个局限性是使用了方便抽样的患者和入选医生，而不是研究所有连续送往放射科进行评估的患者。由于在繁忙的急诊室中保持足够的患者流量会受到时间限制，因此我们不可能连续招募患者。因此，这种抽样方法可能存在患者选择偏差，即某些患者（即疑难杂症患者）可能未被纳入，如果存在这种偏差，可能会导致高估急诊室两点按压超声检查的灵敏度和特异性。我们没有收集患者的人口统计学数据，如体重指数、性别或种族，这可能会影响我们研究中的患者与其他人群的比较。在 238 名接受过放射科双相超声检查的患者中，有 188 名接受了我们的方便抽样调查，这表明在研究期间，我们在急诊室接受下肢深静脉血栓评估的患者总数中获取了 的数据。
The limited depth, contrast, and gain abilities of the portable vascular ultrasound make it attractive for vascular procedures
便携式血管超声仪的深度、对比度和增益能力有限，因此对血管手术具有吸引力
Table 2. Comparison of ED 2-point compression ultrasonographic results to the final reading of the Department of Radiology ultrasonography.*
表 2.ED 2 点压迫超声波检查结果与放射科超声波检查最终读数的比较*。
Subject
Thrombus on ED
CUS
Incompressible
on ED CUS
DOR Ultrasonography Final
Reading
Final Diagnosis
1 0 1 Femoral thrombus not observed but less compressible Common femoral DVT
2 1 1 Femoral thrombus observed with decreased compressibility Common femoral DVT
3 0 1 Distal femoral thrombus with decreased compressibility Distal femoral DVT
4 0 1 Distal femoral thrombus with decreased compressibility Distal femoral DVT
5 1 0 Superficial femoral DVT DVT
6 1 0 Popliteal DVT DVT
7 1 0 Superficial femoral DVT DVT
8 1 1 Midfemoral and popliteal DVT DVT
9 1 1 Nonocclusive DVT in proximal and midfemoral vein DVT
10 0 1 Nonocclusive DVT in midfemoral vein DVT
11 1 0 Partial occlusion of popliteal DVT DVT
12 1 1 Common femoral DVT with popliteal DVT DVT
13 0 1 Popliteal DVT DVT
14 1 1 Common femoral DVT with popliteal DVT DVT
15 0 1 Popliteal DVT DVT
16 0 1 Popliteal DVT DVT
17 1 1 Midfemoral and popliteal DVT DVT
18 1 1 Nonocclusive DVT in proximal and midfemoral vein DVT
19 0 1 Nonocclusive DVT in midfemoral vein DVT
20 1 1 Common and superficial femoral vein, popliteal vein DVT
21 1 0 Superficial femoral DVT DVT
22 1 1 Common and superficial femoral vein, popliteal vein DVT
23 1 1 Common femoral DVT DVT
24 0 1 Nonocclusive DVT in proximal and midfemoral vein DVT
25 1 0 Superficial femoral DVT DVT with cellulitis
26 1 1 Popliteal DVT DVT with PE
27 1 1 Popliteal DVT DVT with PE
28 0 1
Distal femoral and popliteal thrombus with decreased
compressibility
Femoral to popliteal DVT
29 1 1
Femoral thrombus observed but decreased compressibility,
popliteal thrombus observed
Femoral to popliteal DVT
30 1 1
Distal femoral, popliteal thrombus with decreased
compressibility
Femoral to popliteal DVT
31 0 1
Femoral/popliteal thrombus not observed but decreased
compressibility
Femoral to popliteal DVT
32 0 1
Femoral/popliteal thrombus not observed but decreased
compressibility
Femoral to popliteal DVT
33 1 1 Femoral thrombus Femoral DVT
34 1 1 Femoral thrombus Femoral DVT
35 1 1 Thrombus in right femoral vein Femoral DVT and ARF
36 1 1 Thrombus in right femoral vein Femoral DVT and ARF
37 0 1 Occlusive common femoral vein DVT
38 0 1 Occlusive common femoral vein DVT
39 1 1 Popliteal thrombus and decreased compressibility Popliteal DVT
40 0 1
Popliteal thrombus not observed but had decreased
compressibility
Popliteal DVT
41 1 1
Popliteal thrombus, decreased femoral/popliteal
compressibility
Popliteal DVT and PE
42 1 1
Popliteal thrombus, decreased femoral/popliteal
compressibility
Popliteal DVT and PE
0 1
Initial: decreased popliteal compressibility, repeat: popliteal
DVT
44 1 1 New Femoral DVT Femoral DVT
45 0 1 Popliteal DVT Popliteal DVT
, Pulmonary embolism; ARF, acute renal failure.
*In ED-compression ultrasonography columns, " 0 " indicates no thrombus or normal compression (negative result) and " 1 " indicates either a visualized thrombus or an incompressible popliteal or femoral vein (positive result).
*在急诊室压缩超声检查栏中，"0 "表示无血栓或正常压缩（阴性结果），"1 "表示可见血栓或不可压缩的腘静脉或股静脉（阳性结果）。
had a DOR examination result that was initially negative, yet a repeated DOR study result 6 hours later was positive for DVT. (This was considered a positive DVT for study purposes.)
DOR 检查结果最初为阴性，但 6 小时后重复的 DOR 检查结果显示深静脉血栓呈阳性。(就研究目的而言，这被视为深静脉血栓阳性）。
Table 3. ED compression ultrasonography DVT characteristics.
Total
Number
Popliteal Femoral
Total DVT 45 11 20
Incompressible with thrombus 22 3 8
Incompressible only (no thrombus) 17 6 8
Thrombus only 6 2 14
Figure 2. Histogram demonstrating results by operator. The 47 enrolling physicians are plotted on the horizontal axis, with the 199 ED compression ultrasonographic results shown. The single false-positive result occurred as the only enrolled examination for 1 physician operator, and 1 operator enrolled a total of 29 patients.
图 2.按操作者显示结果的直方图。横轴上标出了 47 位报名医生，图中显示的是 199 位 ED 按压超声检查结果。单个假阳性结果是 1 名操作医师的唯一登记检查结果，1 名操作医师共登记了 29 名患者。
because the resolution allows for easy identification of vessels. However, the high-resolution linear array vascular probes (13 to to ) used by the newest ED ultrasonographic machines have a greater resolution than the probe of the Bard Site-Rite. The higher resolution may make it easier to visualize multiple small vessels, which may in turn confuse the operator and make it difficult to correctly identify the popliteal vessels. This raises the question about reproducibility of this study with a high-frequency probe. As operators become more fluent with ultrasonographic technology and as the technology itself evolves, temporal changes can affect the diagnostic test characteristics in this situation. It is likely the results of this study will apply to conventional ED ultrasonographic machines, but this was not tested here.
因为分辨率高，便于识别血管。不过，最新的急诊室超声造影机使用的高分辨率线性阵列血管探头（13 至 至 ）比 Bard Site-Rite 的 探头分辨率更高。更高的分辨率可能更容易观察到多条小血管，这反过来又会使操作者感到困惑，难以正确识别腘血管。这就提出了使用高频探头进行这项研究的可重复性问题。随着操作人员对超声技术的熟练掌握以及技术本身的发展，时间上的变化会影响这种情况下的诊断测试特性。本研究的结果很可能适用于传统的 ED 超声波机，但在此并未进行测试。
Furthermore, the Bard Site-Rite IV only has 2 depth settings, 2 or , which limits the patients who can be evaluated. Despite the prevalence of obesity at our public hospital, our study surprisingly did not have any indeterminate results. One possibility for this is that the limited contrast and gain abilities of the Bard Site-Rite IV may have improved the ED ultrasonographer's ability to identify the vessels, thus reducing the confusion with other smaller vessels that can occur with high-resolution ultrasonography. It is also possible that difficult (ie, obese) patients were avoided. We did not find any evidence to support this bias, and giving the enrolling physician a gift card for each submitted examination encouraged inclusion of all potential subjects.
此外，Bard Site-Rite IV 只有两种深度设置，即 2 或 ，这限制了可进行评估的患者。尽管肥胖症在我们公立医院很普遍，但我们的研究竟然没有发现任何不确定的结果。原因之一是 Bard Site-Rite IV 的对比度和增益能力有限，这可能提高了急诊室超声技师识别血管的能力，从而减少了高分辨率超声造影可能出现的与其他较小血管混淆的情况。也有可能是避免了疑难（即肥胖）患者。我们没有发现任何证据支持这种偏差，而且每次提交检查结果都会给报名医生一张 礼品卡，这鼓励了所有潜在受试者的加入。
The ease of use and ability to quickly find the femoral and popliteal vessels with the portable ultrasonographic machine used in this study was not compared with that of a highresolution ultrasonographic machine, and a study that answers this question could be helpful in explaining the lack of indeterminate results encountered here. Although the minimum number of compressions for each vessel was one single attempt, the actual number of compressions a provider performed was not recorded. Because the study reproducibility could be affected by the compression attempts needed for adequate visualization, subsequent studies may benefit from using a standard number of compressions at each vessel. Despite these limitations, our findings are consistent with those of previous studies, with the exception of our low rate of indeterminate results, and we believe that ED 2-point compression ultrasonography for deep venous thrombosis will be accurate and reproducible, provided the vessels are adequately visualized.
本研究中使用的便携式超声造影机与高分辨率超声造影机的易用性和快速找到股动脉和腘动脉血管的能力没有进行比较，回答这一问题的研究可能有助于解释本研究中遇到的缺乏不确定结果的情况。虽然每根血管的最少按压次数为一次，但没有记录医护人员的实际按压次数。由于研究的可重复性可能会受到为充分显像所需的按压尝试次数的影响，因此在每根血管上使用标准按压次数可能会使后续研究受益。尽管存在这些局限性，但我们的研究结果与之前的研究结果是一致的， ，只是我们的不确定结果率较低。我们相信，只要能充分观察到血管，针对深静脉血栓的 ED 2 点按压超声检查将是准确和可重复的。
Only 47 of 60 eligible physician subjects at our institution enrolled patients, with the majority of those being resident physicians. This may introduce a subgroup or "ultrasonographic interest" bias on the part of the operators, which could inflate estimates of sensitivity and specificity. The operator with the most ultrasonographic experience, a study investigator with ultrasonographic fellowship training but not credentialed as a registered diagnostic medical sonographer, enrolled 9 of the 43 patients with positive deep venous thrombosis examination results and 20 of the 149 patients with negative examination results. Although this accounts for some clustering of data around a single provider, a histogram broken down by operator has been reported so that the reader may interpret these results with clarity (Figure 2). The limited experience and diverse background of the other 46 operators (emergency medicine residents, full- and part-time emergency medicine faculty, and internal medicine and family medicine rotating residents) suggest that any physician with limited ultrasonographic experience can easily acquire the skills necessary to perform ED 2-point compression ultrasonography for proximal lower extremity deep venous thrombosis.
在我们机构的 60 位符合条件的医生受试者中，只有 47 位招募了患者，其中大部分是住院医生。这可能会使操作者产生亚组或 "超声兴趣 "偏差，从而夸大灵敏度和特异性的估计值。超声波检查经验最丰富的操作者是一位接受过超声波检查研究员培训但未获得注册超声诊断医师资格的研究人员，他登记了深静脉血栓检查结果呈阳性的 43 位患者中的 9 位，以及检查结果呈阴性的 149 位患者中的 20 位。虽然这说明了数据在一定程度上是围绕着单个医疗服务提供者的，但我们还是报告了按操作者分列的直方图，以便读者可以清晰地解读这些结果（图 2）。其他 46 名操作者（急诊科住院医师、全职和兼职急诊科教师、内科和家庭医学轮转住院医师）的有限经验和不同背景表明，任何具有有限超声波检查经验的医生都能轻松掌握必要的技能，对下肢近端深静脉血栓进行急诊室两点按压超声波检查。

DISCUSSION

Our results demonstrate good diagnostic accuracy of ED 2-point compression ultrasonography for proximal lower extremity deep venous thrombosis with a portable vascular ultrasonographic machine. In contrast to that of a recent study conducted at an urban academic ED with a heterogeneous group of ED clinicians (attending physicians, residents, and
我们的研究结果表明，使用便携式血管超声造影机进行急诊室两点按压超声造影诊断下肢近端深静脉血栓具有良好的准确性。与最近一项在城市学术急诊室进行的研究相比，这项研究的急诊室临床医生（主治医师、住院医师和急诊科医生）组成了一个不同的群体。
midlevel providers), the sensitivity and specificity of single-visit ED-performed compression ultrasonography was found to be lower, ( CI to ) and ( CI to ), respectively. There was also a difference in the number of indeterminate results. Two methodological differences exist between this study and ours. The first involves the use of a 3point compression (common femoral, superficial femoral, and popliteal) as opposed to 2-point (common femoral, popliteal). The addition of another measured variable increases the chance of error and may partially account for the lower sensitivity and specificity. The second difference involves the use of a 14 to linear format broadband probe compared to the linear probe equipped with our machine. One possible explanation is that the higher frequency probe, which gives much greater detail, may cause the ultrasonographer to focus on superficial veins, lymph nodes, or other fluid-filled areas and misidentify the common femoral or popliteal vessels entirely. We did not measure the opinion of the ultrasonographer, nor did we compare identification of the vessels between high- and low-frequency probes. To our knowledge, this has not been studied before. The study most similar to ours is one that performed an ultrasonographic image quality comparison between an inexpensive handheld ED machine and a large mobile ED system, in which a significant difference was observed between image quality and resolution but not detail. The degree to which improved image quality affects diagnostic accuracy has been questioned, such that a reader's ability to interpret an image correctly may not always improve with increased image quality, resolution, and detail. On conclusion of our study, we did have the general impression that it was easier to identify the vessels with the low-frequency probe, which may have affected our diagnostic accuracy. Although this finding is subjective and was not studied here, we have included this statement to suggest areas of additional research and development. This may be more evident in the hands of inexperienced operators or with the use of color Doppler flow and certainly warrants further investigation.
中级医疗人员），单次就诊时由急诊科实施的压缩超声波检查的敏感性和特异性较低，分别为 ( CI to ) 和 ( CI to ) 。 不确定结果的数量也存在差异。这项研究与我们的研究在方法上有两处不同。首先是使用了三点压迫法（股总动脉、股浅动脉和腘绳肌），而不是两点压迫法（股总动脉、腘绳肌）。增加另一个测量变量会增加出错的几率，这可能是灵敏度和特异性较低的部分原因。第二个不同点是，与我们机器上配备的 线性探头相比，我们使用的是 14 至 线性格式宽带探头。一种可能的解释是，频率较高的探头能提供更多细节，可能会导致超声波技师将注意力集中在浅表静脉、淋巴结或其他充满液体的区域，而完全误认为是股总血管或腘血管。我们没有衡量超声技师的意见，也没有比较高频和低频探头对血管的识别。据我们所知，以前从未对此进行过研究。与我们的研究最相似的一项研究对廉价的手持式急诊室机器和大型移动式急诊室系统进行了超声图像质量比较，结果发现图像质量和分辨率之间存在显著差异，但细节方面没有差异。 图像质量的提高对诊断准确性的影响程度一直受到质疑，因为读者正确解读图像的能力并不总是随着图像质量、分辨率和细节的提高而提高。 在我们的研究结束时，我们确实普遍认为使用低频探头更容易识别血管，这可能会影响我们的诊断准确性。尽管这一发现是主观的，在这里也没有进行研究，但我们还是将这一结论纳入了研究，以建议进行更多研究和开发的领域。在缺乏经验的操作人员手中或使用彩色多普勒血流时，这种情况可能会更加明显，当然值得进一步研究。
One of the 43 deep venous thromboses identified as a positive result in our study (because of incompressibility) (patient 43, Table 2) was initially read as negative by the attending radiologist, despite having abnormal flow augmentation on the Department of Radiology examination. Given the concern of the emergency physician about the decreased compressibility of the femoral vein on ED compression ultrasonography, the emergency physician ordered a second Department of Radiology ultrasonography that was conducted 6 hours after the first. The second examination showed a thrombus of the popliteal vein, as well as decreased compressibility of the femoral vein. This result was classified as positive for study purposes because the second ultrasonography occurred during a single ED visit and was the one used for the final diagnosis for the patient, even though the second Department of Radiology duplex ultrasonography was conducted 6 hours later. This was different from the single false- positive result mentioned above, in which the final Department of Radiology ultrasonography result was read as negative and a repeated Department of Radiology duplex result at 1 week was positive. Theoretically, conventional venography may have identified the above deep venous thromboses initially and, if studied here, could have led to a lower sensitivity of ED 2-point compression ultrasonography for deep venous thrombosis. In our study, however, ED compression ultrasonography was more accurate than Department of Radiology duplex evaluation.
在我们的研究中，43 例深部静脉血栓中的一例（由于无法压缩）最初被放射科主治医生判定为阴性（表 2，43 号患者），尽管放射科检查发现血流异常增强。考虑到急诊医生对急诊室压缩超声波检查中股静脉可压缩性降低的担忧，急诊医生要求在第一次检查 6 小时后进行第二次放射科超声波检查。第二次检查显示腘静脉有血栓形成，股静脉可压缩性降低。就研究目的而言，这一结果被归类为阳性，因为第二次超声波检查是在一次急诊室就诊期间进行的，并且是用于患者最终诊断的超声波检查，尽管放射科的第二次双相超声波检查是在 6 小时后进行的。这与上文提到的单次假阳性结果不同，在后者中，放射科超声检查的最终结果被判定为阴性，而 1 周后重复的放射科双相超声检查结果为阳性。从理论上讲，常规静脉造影术可能会在最初发现上述深静脉血栓，如果在此进行研究，可能会导致急诊室两点加压超声造影术对深静脉血栓的敏感性降低。然而，在我们的研究中，急诊室压缩超声波检查比放射科双相评估更准确。
In a recently published meta-analysis of emergency physician-performed ultrasonography, the studies analyzed were found to have the following methodological problems: a small number of experienced emergency physician operators (range 2 to 8 operators), few registered diagnostic medical sonographer credentialed radiology-based sonographers (less than ), limited details about patient enrollment methods and demographics, limited information about anatomic location of deep venous thrombosis, and the potential for missed calf vein deep venous thrombosis. Although we did not address patient demographics, we do mention that our patients are a sample of those of a typical public hospital in southern California. Detailed information is provided about patient enrollment methods. We provide specific information about the deep venous thrombosis location, and of our radiologybased sonographers were credentialed as registered diagnostic medical sonographers. The large sample of physician operators and limited previous ultrasonographic experience of physicians performing ultrasonography (internal medicine residents with no previous ultrasonographic experience and emergency medicine residents with minimal experience) suggest that the physician operators in our study are similar to those in general community practice.
在最近发表的一项关于急诊医师实施超声波检查的荟萃分析中， ，发现所分析的研究存在以下方法学问题：经验丰富的急诊医师操作者人数较少（2 到 8 名操作者不等），具有放射学资质的注册诊断医学超声波技师人数较少（少于 ），有关患者登记方法和人口统计学的详细信息有限，有关深静脉血栓解剖位置的信息有限，以及可能遗漏小腿静脉深静脉血栓。虽然我们没有涉及患者的人口统计学特征，但我们确实提到了我们的患者是南加州一家典型公立医院的患者样本。我们提供了有关患者登记方法的详细信息。我们提供了有关深静脉血栓形成位置的具体信息， ，我们的放射科超声技师都具有注册诊断医学超声技师资格。医生操作者的样本量大，而进行超声波检查的医生以前的超声波检查经验有限（内科住院医师以前没有超声波检查经验，急诊科住院医师只有极少的经验），这表明我们研究中的医生操作者与一般社区实践中的医生类似。
Although we did not have the ability to study isolated calfvein deep venous thrombosis, recent evidence questions the relevance of detecting calf deep venous thrombosis and the need for long-term anticoagulation. Of 2,098 patients randomized to 2-point ultrasonography and whole-leg duplex ultrasonography (which included detection of isolated calf vein deep venous thrombosis), 2-point ultrasonography had a lower prevalence of deep venous thrombosis compared with whole-leg duplex ultrasonography. The entire difference was accounted for by 65 missed cases of isolated calf deep venous thrombosis. Because the long-term outcome of the 2 groups was found to be similar, the need for detection and treatment of isolated calf deep venous thrombosis may warrant further investigation and thus may not be as critical as previously thought. However, current opinion suggests that duplex ultrasonography of the proximal lower extremity only, when combined with either a normal D-dimer result at presentation or a repeated duplex examination at 1 week (to detect a calf deep venous thrombosis that extended to the proximal veins) in those with negative initial duplex examination results, is thought to be sufficient for exclusion of a calf deep venous thrombosis. In addition, a recent meta-analysis has shown that withholding
虽然我们没有能力研究孤立的小腿静脉深静脉血栓，但最近的证据 对检测小腿深静脉血栓的相关性和长期抗凝的必要性提出了质疑。在随机接受两点式超声波检查和全腿双相超声波检查（包括检测孤立的小腿静脉深静脉血栓）的 2098 名患者中，两点式超声波检查的深静脉血栓发生率低于全腿双相超声波检查。65例遗漏的孤立小腿深静脉血栓造成了整个差异。由于两组患者的长期疗效相似，因此检测和治疗孤立性小腿深静脉血栓的必要性值得进一步研究，因此可能并不像之前认为的那样至关重要。 不过，目前的观点认为，对于最初双相超声检查结果为阴性的患者，如果仅对下肢近端进行双相超声检查，并在就诊时结合正常的 D-二聚体结果，或在 1 周后再次进行双相超声检查（以发现延伸至近端静脉的小腿深静脉血栓），就足以排除小腿深静脉血栓。 此外，最近的一项荟萃分析表明，暂缓进行小腿深静脉血栓形成的治疗，可以有效预防小腿深静脉血栓形成。
anticoagulation after a single negative whole-leg compression ultrasonographic examination is associated with a low risk of deep venous thrombosis in a 3-month follow-up period.
在一次全腿加压超声检查阴性后进行抗凝治疗，在 3 个月的随访期内，发生深静脉血栓的风险较低。
The use of ultrasonographic guidance for ED insertion of central lines has been shown to increase success rates and reduce complications, prompting the Department of Health and Human Services Agency for Healthcare Research and Quality to advocate the use of ultrasonographic guidance for central venous catheter placement. For these reasons, portable vascular ultrasonographic machines may experience increased availability in US hospitals. This may also apply to the ICU setting, in which portable vascular ultrasonographic machines continue to be popular. Given the rate of change with ultrasonographic technology, portable vascular machines may ultimately be replaced in the ED and ICU by larger, higher-resolution, complex machines with widespread applications. If a lowfrequency, simpler machine can produce superior or equivalent results, perhaps the emergency medicine community should investigate the use of this technology or modification of more complex machines to have simpler settings. This may increase the potential use of 2-point compression ultrasonography as an ED proximal lower extremity deep venous thrombosis screening tool.
事实证明，在急诊室插入中心静脉管时使用超声引导可提高成功率并减少并发症， ，这促使美国卫生与公众服务部卫生保健研究与质量局提倡在中心静脉导管置入时使用超声引导。 由于这些原因，便携式血管超声成像仪在美国医院的使用率可能会越来越高。这可能也适用于重症监护室，因为便携式血管超声造影机在重症监护室仍然很受欢迎。考虑到超声波成像技术的变化速度，在急诊室和重症监护室，便携式血管成像仪最终可能会被更大、分辨率更高、应用更广泛的复杂设备所取代。如果低频、简单的机器能产生更好或同等的效果，急诊医学界或许应该研究这种技术的使用，或将更复杂的机器改装成更简单的设置。这可能会增加两点按压超声造影作为急诊室下肢近端深静脉血栓筛查工具的潜在用途。
Despite the emerging opinions that duplex ultrasonography has become the standard, acceptable modality for evaluating the venous system for deep venous thrombosis, contrast venography is still considered the true criterion standard for diagnosing deep venous thrombosis. Because it was prohibitive and potentially dangerous to use contrast venography in all subjects in this study, and especially because it is not currently accepted practice in the ED, we considered the final radiologist interpretation of the Department of Radiologyperformed study sufficient and practical to use as a criterion standard. We recognize that compression ultrasonography is thus a central aspect of both our criterion standard (the Department of Radiology duplex) and our test in question (ED 2-point compression ultrasonography). Because both of these could theoretically miss a deep venous thrombosis and thus miss the actual disease, it would have been ideal to compare this with another imaging modality or provide adequate long-term follow-up. In addition, the argument could be made that we should not be interested in comparing our results to a controversial criterion standard (because this will be contrast venography by convention), but should rather test to see whether ED compression ultrasonography is equivalent to Department of Radiology duplex ultrasonography. Cohen's (0.99) shows that there is near-perfect agreement between the 2 tests. In our patient sample as tested by this physician group, ED compression ultrasonography was therefore equivalent to Department of Radiology duplex ultrasonography. Therefore, irrespective of how the results are analyzed, our data show that compression ultrasonography of the lower extremity with portable vascular ultrasonography can accurately detect proximal lower extremity deep venous thrombosis in the ED.
尽管有新的观点认为双相超声波检查已成为评估深静脉血栓形成的静脉系统的标准、可接受的方式，但 造影剂静脉造影仍被认为是诊断深静脉血栓形成的真正标准。 由于在本研究中对所有受试者使用造影剂静脉造影术过于昂贵，且存在潜在危险，尤其是目前在急诊室还没有被接受的做法，因此我们认为放射科医生对放射科所做研究的最终解释足以作为标准，且切实可行。因此，我们认为压缩超声波检查是我们的标准（放射科二联）和我们的相关测试（急诊室两点压缩超声波检查）的核心内容。由于这两种检查理论上都可能漏诊深静脉血栓，从而错过实际疾病，因此最好能与其他成像方式进行比较，或提供充分的长期随访。此外，还有一种观点认为，我们不应该将我们的结果与一个有争议的标准进行比较（因为按照惯例，这将是对比静脉造影），而应该检验 ED 压迫超声造影是否等同于放射科双相超声造影。Cohen's (0.99) 表明，这两种测试之间的一致性接近完美。因此，在该医生小组测试的患者样本中，急诊室加压超声波检查与放射科双相超声波检查结果相当。 因此，无论结果如何分析，我们的数据都表明，在急诊室使用便携式血管超声仪对下肢进行加压超声检查可准确检测出下肢近端深静脉血栓。
Physician-performed 2-point compression ultrasonography of the lower extremity with a portable vascular ultrasonographic machine, conducted in the ED by this physician group and in this patient sample, accurately identified the presence and absence of proximal lower extremity deep venous thrombosis.
该医生小组在急诊室对该样本患者使用便携式血管超声波机进行下肢两点按压超声波检查，可准确识别下肢近端深静脉血栓的存在与否。
Although our findings support the ACEP policy statement and ACEP clinical compendium's statement that bedside compression ultrasonography is an appropriate method for evaluating lower extremity deep venous thrombosis in the ED, the lower diagnostic accuracy found in recent studies may reflect differences in equipment, training, and study methodology. This suggests that more data are needed before a standard protocol for ultrasonographic evaluation of lower extremity deep venous thrombosis is accepted by the emergency medicine community and applied to general ED practice. Future research should include investigation into the specific anatomic site and number of compressions needed, the role of D-dimer in 2-point compression ultrasonography, the follow-up needed after ED ultrasonography, and the type of ultrasonographic machine, settings, and probe resolution required for optimal diagnostic accuracy.
虽然我们的研究结果支持 ACEP 政策声明和 ACEP 临床简编的说法，即床旁加压超声检查是在急诊室评估下肢深静脉血栓的合适方法， ，但近期研究中发现的较低诊断准确性可能反映了设备、培训和研究方法的差异。这表明，在急诊医学界接受超声波评估下肢深静脉血栓的标准方案并将其应用于普通急诊室实践之前，还需要更多的数据。未来的研究应包括调查具体的解剖部位和所需的按压次数、D-二聚体在两点按压超声造影中的作用、急诊室超声造影后所需的随访，以及达到最佳诊断准确性所需的超声造影机类型、设置和探头分辨率。

Supervising editor: David T. Overton, MD, MBA

Author contributions: LML and TBJ conceived the study and designed the trial, with input during the process by JGC. JGC and TBJ implemented the study, trained physician subjects, explained and advertised the study within the ED, and collected data. TBJ maintained preliminary data collection. JGC maintained final data. JGC drafted the article. JGC revised the article, with contributions from TBJ. JGC and TBJ take responsibility for the paper as a whole.
作者贡献：LML 和 TBJ 构思了这项研究并设计了试验，JGC 在过程中提供了意见。JGC 和 TBJ 实施研究、培训受试医生、在急诊室解释和宣传研究并收集数据。TBJ 负责收集初步数据。JGC 维护最终数据。JGC 起草文章。JGC 对文章进行修改，TBJ 参与其中。JGC 和 TBJ 对本文负全部责任。
Funding and support: By Annals policy, all authors are required to disclose any and all commercial, financial, and other relationships in any way related to the subject of this article that might create any potential conflict of interest. The authors have stated that no such relationships exist. See the Manuscript Submission Agreement in this issue for examples of specific conflicts covered by this statement.
资助与支持：根据《年鉴》政策，所有作者都必须披露与本文主题相关的、可能造成任何潜在利益冲突的任何及所有商业、财务及其他关系。作者已声明不存在此类关系。请参阅本期的《投稿协议》，了解本声明所涵盖的具体冲突实例。
Publication dates: Received for publication January 21, 2010 Revision received June 9, 2010. Accepted for publication July 6, 2010. Available online September 22, 2010.
出版日期：2010 年 1 月 21 日接收发表 2010 年 6 月 9 日收到修订稿。2010 年 7 月 6 日接受发表。2010 年 9 月 22 日可在线查阅。
Reprints not available from the authors.
Address for correspondence: Jonathan G. Crisp, MD, MS, Department of Emergency Medicine, University of California Los Angeles-Olive View Medical Center, 14445 Olive View Dr, N Annex, Sylmar, CA 91342; 818-364-3107, Fax 818-3643268
通讯地址加州大学洛杉矶分校橄榄景医疗中心急诊医学系 Jonathan G. Crisp, MD, MS, 14445 Olive View Dr, N Annex, Sylmar, CA 91342; 818-364-3107, Fax 818-3643268

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