Emergency Physicians (EPs) have performed bedside ultrasound (US) for more than three decades. Today, US is ubiquitous in our specialty. Each year new physicians learn the skill, fresh evidence is brought to light supporting the practice, and novel indications are explored. Technological advances have delivered smaller machines with improved image quality that are less expensive than ever before. Several US manufacturers have developed machines targeted to Emergency Medicine (EM), taking into consideration our specific indications and less-than-forgiving work environment. US training is an important component of Emergency Medicine residency programs and a required core competency procedure of the Accreditation Council for Graduate Medical Education Residency Review Committee.1 There are numerous opportunities for supplementary training in emergency US, ranging from local courses to established fellowship training programs.
Safety considerations have also contributed to the acceptance of bedside US. Sonography is noninvasive, safe in pregnancy, and does not require contrast agents that risk kidney failure, subcutaneous extravasation, and allergic reactions.2 With increasing concern in the medical community over the long-term effects of ionizing radiation, US is recognized as an attractive alternative.3 Additionally, the U.S. Department of Health and Human Services' Agency for Healthcare Research and Quality has highlighted US guidance for central line insertion as 1 of their top 10 recommended practices.4
The intent of this chapter is to provide an introduction to bedside US for the EP. The physician-sonographer should have a general understanding of the physics underlying the properties of an US wave. “Knobology” is a colloquial term used to describe the study of the buttons, dials, switches, and, of course, knobs, on the console of an US machine. It is important that all users have a good sense of their machine's operational functions. Typical machines and transducers used in the ED will be described.
The Paradigm of Bedside US
Bedside US is a relatively new paradigm in clinical medicine. Traditional radiology US involves a break in the patient–physician encounter. The multistep process involves the EP evaluating the patient and determining that an US is warranted, the radiologic technologist performing the study in an US suite, the radiologist reviewing the images and generating a report, and the EP ultimately correlating that information back to the patient (Figure 3-1).
The paradigm of bedside US. The workflow of traditional US utilizing the radiology department (blue circle with red arrows) is a multistep process that may take hours to days to complete. Bedside US (double yellow arrow) establishes an immediate and direct interaction between patient and physician. (Courtesy of Christopher Moore, MD, RDMS, RDCS.)
Bedside US crafts a direct and immediate relationship between patient and EP (Figure 3-1). The technology is placed in the EP's hand for both image acquisition and interpretation. The EP can immediately synthesize US findings ...