LAUSR

To the Editor and Board of the Journal of Clinical Ultrasound: The survey study by Moussa and Stausmire in last month’s publication provoked significant concern among national American College of Emergency Physicians (ACEP) and general Emergency Medicine Pointof-Care Ultrasound (EM POCUS) leadership regarding its conclusions and methodology. Over a span of 20 years the EM POCUS community, through significant scholarly contribution to clinical ultrasound, has demonstrated excellent agreement with imaging specialists in well performed studies spanning areas from vascular surgery, trauma surgery, obstetrics, and radiology to name a few. In stark contrast to the author's conclusions, these studies addressed skepticism within emergency medicine and other fields by demonstrating that emergency physicians make accurate diagnoses and clinical decisions without a need to corroborate their findings using additional imaging tests. Although the questions posed in the article are of potential interest, we are concerned that the methodology has a number of critical flaws and overreaching conclusions that may misinform stakeholders at large. The most notable limitation is the response rate of 12%, a number far below the threshold of valid surveys. Additionally, many respondents indicated that they did not perform ultrasound and onethird were not board-certified emergency physicians, making the sample nonrepresentative of the field of emergency medicine. Of further methodological concern, the authors never described how they developed and validated survey questions leading to potential misunderstanding of their questions. To begin with, the paper lacked a definition for “confirmatory test,” potentially leading to misclassification of answers. For example, the Focused Assessment with Sonography for Trauma (FAST) exam directs unstable patients with intraperitoneal free fluid to the operating room without further testing. However, in some settings it is standard practice to require stable patients with significant mechanisms of injury and negative FAST exams to undergo CT scans to identify occult injury. Without a strict definition of “confirmatory test,” it is difficult to predict how respondents intended to answer the question. Would they request a repeat FAST, or consider a CT scan a “confirmatory test?” Likewise, the diagnosis of foreign body has no well accepted standard and frequently requires multimodal imaging to diagnose depending on the nature of the foreign body. In difficult cases, practitioners may rely on several imaging modalities. Is a confirmatory study during a cardiac arrest another cardiac echocardiogram or an electrocardiogram? In these circumstances the term “confirmatory study” seems inaccurate as local practice may require additional, not confirmatory imaging. The ordering of additional studies is often due to factors outside the emergency physician’s control. Diagnostic limitations of any kind of imaging, demand from consultants who may have little knowledge of POCUS, and nonevidenced based beliefs in the superiority of other imaging modalities may promote ordering additional tests. The authors seem to presume that POCUS operators “rely” on additional imaging, but the survey only asked if providers either rarely or routinely “ordered” confirmatory studies. Systems-based shortcomings, such as lack of access to image archival systems where POCUS results may be compared with sequential studies, may also compel physicians to order additional tests at the behest of other physicians. The survey did not account for many of these plausible external factors for ordering additional studies which limits the conclusions. Another critical flaw is that the authors made no attempt to incorporate hospital credentialing or privileging practices into their analysis. ACEP outlined a guideline for privileging in 2001 suggesting that physicians new to POCUS obtain further comprehensive studies. This study showed that 55.8% of the respondents did not have formal credentialing, and if following ACEP Ultrasound Guidelines, would not have been able to make independent decisions regarding their ultrasound examinations. They would have been required to obtain further comprehensive studies regardless of physician confidence and comfort. The survey made no effort to control for privileging and credentialing status of the respondents. The authors go on to make unsupported leaps to economic conclusions about cost, none of which are accounted for by a survey tool. Since this is not supported by the data it is speculative and better for an opinion article than a scientific one. Point-of-Care Ultrasound is an established and integral part of emergency medicine and now gaining traction in the broader field of medicine. Gaps exist and we suspect the authors meant to draw light on the challenges of EM POCUS regarding frequency of use, credentialing, storage and documentation, training, and acceptance of results by the broader field of practitioners. However, the authors made a large assumption when they insinuated that the only reason Received: 5 June 2018 Accepted: 22 July 2018