Ultrasound in the ED: a different point of view

Editorials / Commentaries

CJEM 1999;1(2):120-121

Many published papers report excellent sensitivity, specificity and accuracy when non-radiologists employ ultrasound (U/S) to detect free intraperitoneal fluid in cases of blunt abdominal trauma (BAT). In this setting, it is best to view the FAST (focused abdominal sonogram in trauma) as a noninvasive diagnostic peritoneal lavage (DPL): It tells us whether there is free intraperitoneal fluid but does not determine the specific parenchymal injury. In other words it is a screening tool.

Why is this important? In abdominal trauma, the single most important criterion for laparotomy is the rapid demonstration of hemoperitoneum.¹ But unanswered questions remain. What is the role of FAST in patients with less severe trauma who will be discharged from the ED, and in what situations should we be doing serial studies? If emergency physicians (EPs) perform FAST, does this improve patient care and outcomes? While there is evidence that 2-dimensional echocardiography in the hands of emergency physicians improves time-to-diagnosis, survival rate and neurological outcome in patients with penetrating cardiac injuries,² I am unaware of studies showing improved patient outcomes when FAST is added to the blunt abdominal trauma algorithm. Nevertheless, it is clear that in many trauma centres, FAST decreases the use of DPL, which is invasive, nonspecific, and is associated with a high rate of non-therapeutic laparotomy and the attached morbidity. In addition, in centres using FAST as a screening modality, the number of abdominal CT scans has decreased significantly, reducing costs.³ Non-radiologists who perform FAST rarely bill for the procedure, which leads to additional savings.

Other indications for ED bedside U/S include life-threatening conditions such as cardiac tamponade, ectopic pregnancy and suspected abdominal aortic aneurysm. As a busy emergency physician, I don't have the time to perform detailed abdominal or pelvic scans, nor do I want to! Because EPs have specific and limited needs, it is inappropriate to apply the same U/S training standards to emergency physicians and radiologists. Many studies show that, to address the above conditions, we do not need 3 months of training and 500 examinations, as stipulated by the American Institute of Ultrasound Medicine! Even the American College of Emergency Physicians' proposed 40-hour curriculum and 150 examinations is more than we require for focused U/S in the ED.⁴ Some US emergency physicians who perform detailed bedside U/S see only 2 patients per hour or work in departments with an abundance of house staff. How many Canadians can say the same? Fifteen minutes is the most time I want to spend scanning.

Can EPs and radiologists collaborate to provide timely focused bedside scans? This might be ideal; however, in our tertiary care trauma centre, the responsibility for ED U/S has been delegated to the radiology residents on call, who are also responsible for all other after hours imaging procedures. As you can imagine, FAST is not always as fast as one would wish. In addition, when these residents are called to the ED to perform bedside U/S, other imaging studies and their interpretations are delayed, which impacts negatively on ED patient flow. Moreover, there is constant turnover of the junior residents who provide this service. Do they have experience with 500 scans prior to performing and interpreting ED scans? This would be less of a recurring problem if a stable complement of EPs gained U/S experience over time.

Why are radiologists not supportive of such an arrangement? Are they concerned that once EPs master the focused U/S, we will go on to do detailed scans and decrease the number of radiology referrals? Perhaps they fear that emergency physicians would do the easy scans and refer only the difficult ones. Not likely. I don't want to be a radiologist! I am only interested in a few selected life-threatening conditions. Turf wars should not distract us from good patient care.

Finally, let it be said, "no department has ownership of a technology."⁵ That is true, whether we are talking about a laryngoscope, a slit lamp or an ultrasound.

References

1. Boulanger BR, Brenneman FD, McLellan BA, Wherrett L, Rizoli SB, Culhane J, et al. Emergent abdominal sonography as a screening test in a new diagnostic algorithm for blunt trauma. J Trauma 1995;39:325-30.
2. Plummer D, Dick C, Ruiz E, Clinton J, Brunette D. Emergency department echocardiography improves outcome in penetrating cardiac injury. Ann Emerg Med 1992;21:709-12.
3. Healey MA, Simons RK, Winchell RJ, Gosink BB, Casola G, Steele JT, et al. A prospective evaluation of abdominal ultrasound in blunt trauma: Is it useful? J Trauma 1996;40:875-83.
4. Mateer J, Plummer D, Olson D, Jehle D, Overton D, Gussow L. Model curriculum for physician training in emergency ultrasonography. Ann Emerg Med 1994;23:95-102.
5. Rozycki GS, Shackford SR. Ultrasound: what every trauma surgeon should know. J Trauma 1996;40:1-4.