Special Report

The State of Emergency Ultrasound and the Standard of Care

by Edward P. Monico, MD, JD, FACEP, FCLM, Assistant Professor, Section of Emergency Medicine, Department of Surgery, Yale University, New Haven, CT

Introduction

Ultrasound is a modality requiring proficiency in both cognitive (indication and interpretation) and psychomotor (hands on) skills. Traditionally, ultrasound images obtained on emergency patients were acquired and interpreted by radiologists. However, limited access to emergency ultrasound has led emergency physicians (EPs) to become proficient in the acquisition and interpretation of ultrasound images performed for diagnostic and therapeutic reasons on emergency patients. Emergency physicians must now ask whether EP-performed ultrasound represents a convenient option or a legal obligation. This article focuses on the history of EP-performed ultrasound and whether this imaging modality triggers a new standard of care in emergency medicine.

While technology may not have been driving the evolution of emergency ultrasound, it certainly had its hand on the wheel. Compared to the first ultrasound instrument that was introduced during the 1950s, current ultrasound devices are smaller, faster, and more portable.1 However, the technological advance most responsible for putting the ultrasound probe into the hands of the EPs was the development of real-time imaging. The procurement of images generated contemporaneously with the clinical exam and the ability to visualize continuous motion both provide valuable information during the early management of severely ill and injured patients.

Ultrasound's utility in the detection of free fluid in the peritoneal cavity was discovered in 1970.2 It was not long before case reports appeared in the literature advocating ultrasound for the evaluation of patients who sustained blunt abdominal trauma.3,4 The Focused Assessment with Sonography for Trauma, or FAST exam, followed this research and became the prototype emergency ultrasonographic exam performed by emergency physicians and trauma surgeons. Subsequent research sought other indications for EP-performed ultrasonography. These include: abdominal aortic aneurysm, ectopic pregnancy, thoracoabdominal trauma, pericardial effusion, determination of cardiac activity, biliary disease, renal tract disease, evaluation for DVT, and procedural guidance. Knowing at what point a legal obligation arises for EP's to perform emergency ultrasound requires an understanding of the role of the standard of care and negligence law.

Tort Law

The tort of negligence contains three elements:

1. the existence of a duty;
2. a departure from customary and usual practice; and
3. that the departure was a substantial cause of injury to the patient.
A plaintiff in a medical malpractice action must prove all of these occurred to prevail.5 Typically, to satisfy this burden, plaintiffs use expert witnesses to distinguish the medical care in question from care regarded as acceptable by practicing physicians who are similarly situated. This "standard of care," therefore, is the legal vernacular for acceptable care by which all other care is measured.

Legal Precedent

The relationship between technology and medical liability is not novel to EP-performed ultrasonography. As one medical historian puts it, "…the development and implementation of new technologies and procedures have played a consistent and central role throughout the history of medical malpractice."6 Studies of specific technologies and their associated liability indicate that claims increase when a new technology is introduced, and then level off over time. During a technology's infancy, however, there may be little evidence-based data that clearly define a standard of care. Case law provides some insight on how liability can arise in the absence of a clearly defined standard of care.

For example, in 1990 in Washington v Washington Hospital Center, the District of Columbia Court of Appeals affirmed a lower court's verdict against the hospital for medical malpractice when it failed to implement pulse oximetry to monitor anesthetized patients.7 To arrive at its decision, the court considered hospital protocols, alumni newsletters, and personal correspondence between hospital administrators to define the standard.

As technology carves out new standards of care for physicians it also widens the schism between physicians who are able to comply from those who are not. While cost represents the patriarchal hurdle to the dissemination of burgeoning technologies, such as pulse oximetry, other factors contribute to the inertia associated with the widespread implementation of ultrasonography in emergency departments.

Acquired Skill

Ultrasound is a modality requiring proficiency in both cognitive (indication and interpretation) and psychomotor (hands on) skills. It has been suggested that training in both image acquisition and image interpretation must be provided through curricula that include didactic lectures, demonstrations, and technical skill laboratories.8 Ultrasound is not only a learned specialty, but also one that requires maintenance of skills and familiarity with technology. While many emergency physicians currently emerging from training programs are well versed in the use of ultrasound, others with earlier training may be less acquainted with it.

Dissemination of Emergency Ultrasound

Despite the American College of Emergency Physician (ACEP) policy statement regarding ultrasound stating that "bedside ultrasound evaluation, including examination, interpretation, and equipment, should be immediately available 24 hours a day for emergency patients"9 and that "emergency ultrasound procedures are standard emergency physician skills," penetration into community emergency departments has been slow. A longitudinal survey by the American Board of Emergency Medicine found that only 21% of board certified emergency physicians "personally perform bedside emergency ultrasound."10

Emergency Ultrasound as a Standard of Care

Despite access limitations and training hurdles, evidence suggests that emergency ultrasound should become standard of care practice in certain clinical scenarios. In 2001, under its "Evidence-Based Practice Program," the Agency for Healthcare Research and Quality (AHRQ) published Making Health Care Safer: A Critical Analysis of Patient Safety Practices.11 The AHRQ publication detailed ways to decrease medical errors, with a chapter devoted to ultrasound-guided central venous access. The chapter noted that patients "with one or more risk factors, (e.g., critically ill patients on positive pressure ventilation with generalized edema and coagulopathy), may reap the greatest benefit" from this modality.12

In an addendum to the report, patient safety practices were rated by strength of evidence into one of five categories, from "lowest impact and/or strength of evidence" to "greatest strength of evidence regarding their impact and effectiveness." Use of ultrasound guidance to decrease morbidity from central venous catheterization was placed in the highest category, reflecting the greatest strength of evidence.13 It should also be noted that among the 11 recommendations with the greatest strength of evidence, ultrasound guidance for central venous access was one of only two with an implementation cost/complexity that was rated as "high."

In addition to evidence from the AHRQ report, the ACEP policy statement specifically notes that "the use of ultrasound imaging by emergency physicians is appropriate in clinical situations ... and procedures that would benefit from the assistance of ultrasound."

Future Considerations

Future consideration should include ways to increase penetrance of emergency ultrasound into community emergency departments. The academic literature should strive for clarity when describing clinical scenarios where the standard of care includes ultrasound as either a diagnostic or therapeutic modality. Lastly, professional organizations should factor into the calculus the time to acquire new skills and equipment before formulating policy statements and obligating practitioners to a standard the practitioners cannot immediately conform to.

Summary

As the expectation that EP's acquire and interpret ultrasound images grows, so will the obligation. Policy statements from professional organizations and federal practice guidelines contemplate the use of ultrasound in emergency departments. The language used in these recommendations might trigger a standard of care in light of previous court opinions regarding the legal obligation to use new medical technologies.

References

1. Kendall JL, Hoffenberg SR, Smith RS. History of emergency and critical care ultrasound: The evolution of a new imaging paradigm. Crit Care Med 2007;35:S126-S130.

2. Goldberg BB, Goodman GA, Clearfield HH. Evaluation of ascites by ultrasound. Radiology 1970;96:15-22.

3. Kristensen JK, Beumann B, Kuehl E. Ultrasonic scanning in the diagnosis of splenic heamatomas. Acta Chir Scand 1971;137:653-657.

4. Asher WM, Parvin S, Virgillo RW, et al. Echographic evaluation of splenic injury after blunt trauma. Radiology 1976; 118:411-415.

5. Epstein RA. The Negligence issue. In: Epstein RA. Cases and Materials on Torts. 6th ed. New York, NY: Aspen; 1995:165-167.

6. De Ville KA. Medical Malpractice in Nineteenth Century America: Origins and Legacy. New York: New York University Press; 1990.

7. Washington v Washington Hospital Center, District of Columbia Court of Appeals, 1990. 579 A.2d 177.

8. Heller MB, Mandavia D, Tayal VS, et al. Residency training in emergency ultrasound: fulfilling the mandate. Acad Emerg Med 2002;9:835-839.

9. Use of Ultrasound Imaging by Emergency Physicians. American College of Emergency Physicians (ACEP) Policy Statement #400121, Approved June 2001.

10. Ling LJ, Gallagher JE, Korte RC. Bedside ultrasonography in emergency medicine training programs. Acad Emerg Med 2003;10:912.

11. Making Health Care Safer: A Critical Analysis of Patient Safety Practices. Evidence Report/Technology. Assessment: Number 43. AHRQ Publication No. 01-E058, July 2001. Agency for Healthcare Research and Quality, Rockville, MD. Available at: www.ahrq.gov/clinic/ptsafety. Accessed on 9/7/07.

12. Rothschild JM. Ultrasound guidance of central vein catheterization. Chapter 21. In: Making Health Care Safer: A Critical analysis of Patient Safety Practices. Evidence Report/Technology Assessment: Number 43 AHRQ Publication No 01-E058, July 2001. Agency for Healthcare Research and Quality, Rockville, MD. Available at: www.ahrq.gov/clinic/ptsafety/chap21.htm. Accessed on 9/7/07.

13. Patient Safety Practices Rated by Strength of Evidence. Chapter 57. In: Making Health Care Safer: A Critical Analysis of Patient Safety Practices. Evidence Report/Technology Assessment: Number 43. AHRQ Publication No. 01-E058, July 2001. Agency for Healthcare Research and Quality, Rockville, MD. Available at: www.ahrq.gov/clinic/ptsafety/chap57.htm. Accessed on 9/7/07.