PREHOSPITAL ULTRASOUND

Introduction

Ultrasound (US) is a useful diagnostic tool for use in hospitals. It is noninvasive and inexpensive, and causes no radiation exposure. Besides radiologists, many emergency physicians use US to assist in their decision making during critical conditions [1]. With the current improvement in technology, US machines have become more portable and are available with a better resolution. Ziegler et al [2] reported that a portable device had approximately 90% accuracy compared with high-end devices. US machines such as PRIMEDIC HandyScan, V-scan, and Sonosite are commonly used as portable devices in prehospital settings.

US has been brought to prehospital settings as a result of the recent advances in technology [3]. A prehospital setting is a unique, most likely noisy, and often limited space. Traditionally, diagnostic tools used in prehospital settings are based on history taking and physical examination.

Physical examination alone cannot be sufficient to diagnose certain conditions [4]. In addition, many studies suggested that prehospital US can change the final diagnosis and treatment [5,6]. Prehospital US has a variety of applications, such as focused assessment with sonography in trauma (FAST) [5], assessment of cardiac arrest [7], lung US (mainly in pneumothorax) [6,8], and others. Countries that have studied prehospital US extensively include Germany, France, Italy, and the United states [9]. Literature was reviewed and discussed in the following sections.

Feasibility of US in a prehospital environment

Because a prehospital space is unique and limited, a US machine should be smaller in size but should have better image quality. Some studies performed US at the scene, and others in a vehicle, such as an ambulance or a helicopter. If performed at the scene, the delivery time to hospital may be prolonged, and if performed in a helicopter or an ambulance, the transporting environment may influence the scan. There are studies of prehospital US in a fixed wing and helicopter, which showed good results. However, Melanson et al [10] reported in their study that the lack of sufficient time during helicopter transport and a proper lighting system in the helicopter can compromise the results of FAST examination. Snaith et al [11] reported that FAST and abdominal aortic aneurysm (AAA) performed in a static and ground ambulance is of good quality due to the availability of sufficient time and is comparable to that performed at the emergency department.

In Taiwan, emergency medical services mainly involve ground ambulances, and most of the ambulance beds are located at the left side; hence, left-hand-based practice may be helpful for performing the scan. Fixation of machines to the frontal areas of ground ambulances may be helpful in reducing shaking.

Educating paramedics about US

Many studies have invested in the learning curve for US, especially in FAST. They concluded that a 1-day course,including lecture and hand-on practice, can generate good accuracy and competency [12]. Heegaard et al [13] designed a FAST training course, which lasted 7 hours, for emergency nurses and paramedic flight crews; they reported 100% sensitivity and specificity in nontrauma patients, and 60% sensitivity and 93% specificity in trauma patients after 1 year of training. Kim et al [14] also reported that a 4-hour FAST training course for intermediate emergency medical technicians (EMT) resulted in 61% sensitivity and 96.3% specificity.

USEFUL

USEFUL: Ultrasound Exam for Underlying Lesions Incorporated into Physical Exam
Jon Steller, MD, Bianca Russell, MD, Shahram Lotfipour, MD, MPH, Graciela Maldonado, MD, Tim Siepel, MD, Halsey Jakle, MD, Stacy Hata, BS, Alan Chiem, MD, RDMS, John Christian Fox, MD, RDMSDisclosures
Western J Emerg Med. 2014;15(3):260-266.

ABSTRACT

Introduction: The Ultrasound Screening Exam for Underlying Lesions (USEFUL) was developed in an attempt to establish a role for bedside ultrasound in the primary and preventive care setting. It is the purpose of our pilot study to determine if students were first capable of performing all of the various scans required of our USEFUL while defining such an ultrasound-assisted physical exam that would supplement the standard hands-on physical exam in the same head-to-toe structure. We also aimed to assess the time needed for an adequate exam and analyze if times improved with repetition and previous ultrasound training.

Methods: Medical students with ranging levels of ultrasound training received a 25-minute presentation on our USEFUL followed by a 30-minute hands-on session. Following the hands-on session, the students were asked to perform a timed USEFUL on 2–3 standardized subjects. All images were documented as normal or abnormal with the understanding that an official detailed exam would be performed if an abnormality were to be found. All images were read and deemed adequate by board eligible emergency medicine ultrasound fellows.

Results: Twenty-six exams were performed by 9 students. The average time spent by all students per USEFUL was 11 minutes and 19 seconds. Students who had received the University of California, Irvine School of Medicine's integrated ultrasound curriculum performed the USEFUL significantly faster (p< 0.0025). The time it took to complete the USEFUL ranged from 6 minutes and 32 seconds to 17 minutes, and improvement was seen with each USEFUL performed. The average time to complete the USEFUL on the first standardized patient was 13 minutes and 20 seconds, while 11 minutes and 2 seconds, and 9 minutes and 20 seconds were spent performing the exam on the second and third patient, respectively.

Conclusion: Students were able to effectively complete all scans required by the USEFUL in a timely manner. Students who have been a part of the integrated ultrasound in medicine curriculum performed the USEFUL significantly faster than students who had not. Students were able to significantly improve upon the time it took them to complete the USEFUL with successive attempts. Future endpoints are aimed at assessing the feasibility and outcomes of an ultrasound-assisted physical exam in a primary care setting and the exam's effect on doctor-patient satisfaction.

Introduction

Records of Hippocratic physical examinations, influenced by the Egyptian, Cretan and Babylonian exams taught before them, included: careful history taking, inspection, palpation, and direct auscultation, and are a tradition that has continued on for thousands of years.[1] It is a great model, yet it is one that has seen few technological advances. Progress was made with the invention of the stethoscope by Laennec in 1816, and was further improved upon by Leyton, Kerr, Bowles, Rappaport, Sprague and Littmann. As newer stethoscopes improved the diagnostic sensitivity and specificity of auscultation, they were implemented into the physical examination. For Ramsay once wrote of Dr. Leyton in the British Medical Journal in 1916, "In spite of careful inquiry into the history of cases and in spite of the many accurate methods of investigation which are nowadays at our command, we cannot invariably form a perfectly definite opinion as to the cause of a patient's symptoms. Any new instrument, therefore, which can help us in our decisions should be of real use to the profession."[2] While his message encourages progress, utilization of new tools in medicine requires a detailed examination of risks and benefits. In modern medicine, we struggle to balance the cost of innovation, time constraints, management of incidental and benign exam findings, patient satisfaction, and managed health care. Our skepticism and curiosity of medical advances drive the use of the scientific method to investigate such developments before they are accepted and implemented by the community of physicians—before they can drive progress.

Over the years, various uses of bedside ultrasound have been adopted by specialties including emergency medicine, obstetrics and gynecology, and trauma. While its use in those fields has been rigorously studied in clinical settings and is the preferred first-line imaging modality for assessment of many of the organs in the abdomen and pelvis,[3] little has been reported on its role in an outpatient primary care setting and this has inspired us to consider the possible role of ultrasound as an addition to the standard physical exam. Given the recent affordability and improved image quality of bedside ultrasound units, we believe bedside ultrasound could be the new figurative stethoscope.

With this first paper, our primary endpoints were to examine the feasibility and time requirements of a medical student-performed ultrasound-assisted physical exam, termed the Ultrasound Screening Exam for Underlying Lesions (USEFUL), wherein students with varying levels of expertise would be evaluated on their ability to correctly and efficiently image individual organs from head to toe. We also sought to define our ultrasound-assisted physical exam for further medical student education and for clinicians interested in integrating ultrasound into their physical exams. Aware of the time restraints for physicians in outpatient clinics, we determined six minutes or less would be an acceptable length for a USEFUL and hoped this would be a reasonable goal. The USEFUL was developed by students and faculty interested in establishing a role for bedside ultrasound in the primary and preventive care setting with the hope that, in the future, an ultrasound-assisted physical exam that would take approximately six minutes might supplement the standard hands-on physical exam.

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