SonoMetaAnalysis: Errors in Emergency Ultrasound – When/What/Why & the lawsuits #FOAMed

In the July 2013 issue of Critical Ultrasound Journal, the authors did a meta-analysis of all studies relating to emergency ultrasound and the diagnostic errors that occur and Ill explain why It’s fascinating. When you read through the details, the reasons are clear and the issues may be obvious. The authors (from Italy who practice ultrasound in different settings with description of emergency ultrasound a bit different than the way we do it here) searched utilizing different association of the following terms from 1990-2013: (1) emergency ultrasonography, (2) error, (3) malpractice and (4) medical negligence –  restricted to human studies and to English-language literature. The abstract of 171 articles appeared appropriate while other articles were recognized by reviewing the reference lists of significant papers. The full text of 48 selected articles was reviewed.

I do disagree with some of the way the authors described emergency ultrasound. I believe in their effort to show their study’s importance, they state: “Emergency US is particularly susceptible to errors, more than any other diagnostic imaging technique: in fact, the misinterpretation of sonographic images should be considered as a serious risk in US-based diagnosis [8]”  – they are referencing an article by radiologists on US artifacts on clinical sonography. So, that’s weird.

Another item that I felt was strange was that many of the references to emergency ultrasound were actually those done by radiologists. I couldnt find one emergency medicine ultrasound article. Thi sis likely due to the practice differences between europeans and Americans with emergency ultrasound, but ….hmmm, it gets even more interesting, and I will likely get even more critical. Im sure the radiologists did an outstanding job in their (or their lab tech’s) image acquisition, but the reasons for diagnostic errors stated by the authors of this study now make sense when you take into account the above:

Reasons for Errors in Emergency Ultrasound: “Causes of error in emergency ultrasonography are multifactorial, frequently exist in combination as in other diagnostic imaging techniques [9,10] and include: lack of attention to the clinical history and examination, lack of communication with the patient (who may be uncooperative), lack of knowledge of the technical equipment, use of inappropriate probes, inadequate optimization of the images, failure of perception, lack of knowledge of the possible differential diagnoses, over-estimation of one’s own skill, failure to suggest further ultrasound examinations or other imaging techniques (such as CT or MRI) [1116]”

The authors then go on to further describe the errors. The discuss the importance of the amount of gel, the correct probe used, the adequate technique, and how artifacts can get in the way. They also state something that i completely agree with – it also depends on the operator. But, they use the example of:  “Modern ultrasound equipment is certainly adequate for producing images that permit diagnosis of anomalies such as open lumbosacral spina bifida or atrioventricular septal defect. However, such diagnoses can only be made if considerable operator skill is associated with knowledge and experience.” So, not sure how to put this, but that’s NOT emergency ultrasound. So, I cannot relate. But, good on those who do it in emergency practice…who am I to say differently – you never know, as our scope of practice continues to increase.

The authors finally discuss errors in the emergency setting, again done by radiologists with references authored in radiology literature from over 10-15 years ago…. and state what we all know and can appreciate: “Quick diagnosis and treatment of patients with whom we have had no previous contact, and who, quite often, may be uncooperative, and/or under the influence of alcohol or drugs creates an environment with significant risk [27]. The frequency of reported “missed diagnoses” depends on how the frequency of error was assessed: based on trauma registries, error rates were approximately 2% [28], while retrospective chart review found approximately 40% [29], and retrospective review of all admissions revealed missed or delayed diagnoses of approximately 8%-10% [2830]……Moreover, the sonographer should evaluate the patient in terms of physical constitution (in obese patients, the thickness of subcutaneous fat and the sound-attenuating properties of fat present challenges) and the presence of conditions potentially limiting the examination (such as obliged decubitus, scars, etc.). The sonographer should be aware of the limitations of the technique in the evaluation of the traumatized patients, asking for other diagnostic imaging procedures (Multidetector row Computed Tomography).” – The authors dont state the errors made nor any litigation made in the emergency setting – interesting, right? That may be because the studies that were queried were not including those of emergency medicine bedside, limited, focused, goal directed, – or whatever you want to call it – ultrasound. There was something interesting though:

As far as litigation is concerned, the authors state ” The earliest litigation related to diagnostic ultrasound occurred in 1974 and involved obstetric measurements. Before 1974, images were so difficult to interpret that ultrasonography was considered of little value apart from obstetric measurement data and for characterizing masses as cysts [19]” They reference an article by J Ultrasound in Medicine done by ObGyn and is a fascinating read on ObGyn litigation as relating to ultrasound, but also does not necessarily speak about emergency ultrasound and our limited studies that we perform. That article states (in relation to ObGyn litigation): “There has been a change in the main target of litigation over time: in the 1980s, ectopic pregnancy was the most common reason for litigation; today, litigation related to a missed fetal anomaly is the most frequent indication. Invented lesions, often seen in past years, almost never occur today. With greater adherence to guidelines, failure to perform sonography for a recognized indication has become a cause of litigation. Well-recognized obstetric ultrasound guidelines, in one respect, provide protection for those who perform faultless series and yet find no abnormalities when they are present and, in another respect, cause problems for those who do not document all the images required by the guidelines when abnormalities are subsequently found.”   Why is this interesting? Well, one of the best studies to date on true emergency medicine ultrasound litigation comes from Dr. Michael Blaivas and Dr. Pawl. First off, there were no law suits on emergency physicians who performed and interpreted bedside ultrasound studies in their review of 659 cases. But, there was one on a physician who chose not to perform it when it was available and indicated – and ectopic pregnancy case.

Lastly, I do agree with this : “Ultrasound scanners, however, are relatively inexpensive and highly effective in the hands of a trained operator. More importantly, ultrasound is a “sustainable technology” for developing and impoverished nations because of its relatively low cost of purchase, low cost for maintenance and supplies, portability, and durability in comparison with all other imaging modalities [47]. Moreover, early education of operators is a priority that can begin to be addressed in medical school. The practice of ultrasound has clearly been shown to be operator-dependent, and the way to train better operators is to start early, provide opportunities for practice, and standardize curriculum that will ultimately align with residency requirements in the various specialties [48]” – This latter reference was the first emergency medicine one I saw – Nice job Dr. David Bahner ! (who was the coordinator of the Ultrasound in Medical Education at AIUM in April 2013).

Other great articles relevant to this and what we should do about incidental findings:

Blaivas M, Pawl R. Analysis of lawsuits filed against emergency physicians for point-of-care emergency ultrasound examination performance and interpretation over a 20-year period. Am J Emerg Med. 2012 Feb;30(2):338-41. doi: 10.1016/j.ajem.2010.12.016. Epub 2011 Jan 28.

Lanitis S, Zacharioudakis C, Zafeiriadou P, Armoutides V, Karaliotas C, Sgourakis G. Incidental findings in trauma patients during focused assessment with sonography for trauma. Am Surg. 2012 Mar;78(3):366-72

Fox JC, Richardson AG, Lopez S, Solley M, Lotfipour S. Implications and approach to incidental findings in live ultrasound models. West J Emerg Med. 2011 Nov;12(4):472-4. doi: 10.5811/westjem.2011.2.2054.


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