POCUS

An Uncommon Technology That Enhances Care

KEVIN ROTH, DO, FACOEP DIRECTOR, POINT OF CARE ULTRASOUND PROGRAM DIRECTOR, EMERGENCY ULTRASOUND FELLOWSHIP

Point of care ultrasound (POCUS) is not new but, with enhancements in ultrasound technology, it is expanding rapidly. These improvements include image quality, instrument portability, image archiving, and the introduction of artificial intelligence. Many years ago, 20 to be exact, I was finishing my Emergency Medicine Residency. I was fortunate to train under a program director who was one of the pioneers of Emergency Ultrasound. This director was willing to teach, and I became deeply interested. In my mind this was a strategy to care for patients with better accuracy in diagnosis than by physical exam alone. Throughout my residency I learned to perform and interpret bedside ultrasound but, the POCUS educational experience is quite variable for many other physician learners. Let’s jump ahead to today’s world. The leaders of our residency have deemed this such an important skill for practicing physicians that it has become a graduation requirement for all our residents.

So, what is POCUS? POCUS is an ultrasound that is performed and interpreted by the same physician who is holding the ultrasound probe. They know the history, have performed a physical exam, and now are completing a preliminary evaluation. This evaluation is performed independent from our Radiology colleagues. Radiology-performed ultrasound is a comprehensive study performed within the radiology suite by a technologist and later is interpreted by a Radiologist. In contrast, POCUS is a limited, focused exam used to provide rapid answers to clinical questions or guide invasive procedures. It is available 24 hours a day, is at the bedside, and provides near immediate results. Some diagnoses become evident as soon as the probe touches the area of investigation.

So, why perform POCUS? POCUS has been extensively studied and has been found to enhance patient care. It specifically reduces time to diagnosis, boosts efficiency, and improves patient safety and satisfaction. A counterpart of mine, J. Christian Fox of UC Irvine, shares the following and I paraphrase, “there are many patients who would not have lived had they gone to another emergency department” when he speaks of a department that performs POCUS.

The list of POCUS applications is long but, is divided into two main categories – diagnostic and procedural guidance. Procedural guidance simply put makes us better in performing central lines, lumbar punctures, thoracentesis, etc. This has been found to be such a powerful tool in patient care we teach our nurses to perform ultrasound-guided peripheral IV placement on our most difficult access patients. We also perform ultrasound-guided nerve block in our hip and femur fracture patients which is widely known to reduce morbidity and mortality, especially in our elderly population.

Diagnostic POCUS categories can be broken down in several ways but, for quick reference there are three main types – resuscitative, emergent, and urgent. Resuscitative POCUS looks for causes of cardiac arrest or near arrest. POCUS answers questions such as, is there cardiac tamponade, severe right heart strain seen with a massive pulmonary embolus, or left ventricular failure? Emergent uses include the evaluation of the aorta for aneurysm, renal to search for hydronephrosis, or pelvic which evaluates for the presence or absence of an intrauterine pregnancy when an ectopic pregnancy is considered. Finally, the urgent category is used frequently as it includes soft tissue to determine abscess versus cellulitis and musculoskeletal in the diagnosis of tendon, bone, or joint pathology. While the above list is incomplete it demonstrates the breadth of POCUS use in medicine.

To further highlight the use of POCUS I would like to introduce three cases to illustrate its use in practice. The first case takes us back to the beginning of the COVID pandemic. Before we had nasal swabs to diagnosis COVID, we had POCUS. Our group had found viral pneumonia with POCUS before the pandemic but, infrequently. POCUS became an invaluable tool with COVID’s migration to the United States. I vividly recall the early days of the pandemic when two patients presented almost simultaneously with profound hypoxia and respiratory distress. I was performing POCUS teaching rounds with my residents and discovered a pattern on lung ultrasound that made me stop and inform the attending physician in charge of those patients’ clinical care – “I think they have COVID pneumonia.” A CT scan verified those early cases but, we soon abandoned CT scanning and performed both POCUS lung and ECHO exams on potential COVID patients to establish early diagnoses. Not only could we diagnose COVID with POCUS but, also determine the severity of lung injury as well as lung recovery. Views of both normal and COVID lung patterns are drastically different (Image 1). A normal lung will have an ultrasound artifact known as A lines. These A lines are evident in the horizontal plane and appear white or hyperechoic. The pleural line in the normal lung is smooth in appearance. In COVID lung the A lines are replaced with B lines. These vertical B lines are also white or hyperechoic. They signify interstitial thickening. COVID lung can also display pleural changes which generate an irregular pleural line appearance.

Case two involves a patient who presents with a visual field deficit. Eye complaints are common in medicine. A detailed exam includes an external exam with a slit lamp, an intraocular pressure reading, and an attempt to view the retina and optic disc with an ophthalmoscope. Often this exam leaves the physician with continued questions as to the patient’s diagnosis. While many types of pathology can be identified with Ocular POCUS, one of the mainstays is diagnosing a retinal detachment. The normally smooth and adherant retinal layer is replaced by an

Continued on page 8 elevated often “wormlike” projection into the center of the eye. The cause of the patient’s symptoms were indeed found to be a retinal detachement as displayed in this Ocular POCUS transverse view of the eye (Image 2).

The final case is of a young patient who presents with an extended history of worsening dyspnea on exertion. Initial testing was unremarkable. The patient then presented to the emergency department with worsening symptoms, which now occurred at rest. A POCUS ECHO was performed revealing the cause of the patient’s symptoms, a left atrial myxoma (Image 3).

Those three cases highlight the use of POCUS. In our emergency departments we perform thousands of POCUS examinations and ultrasound-guided procedures yearly. We embed the images and interpretations into patients’charts at the completion of each exam. This allows for quality assurance procedures and provides our subspecialists with the ability to view and act on the findings in real time.

The final question is how do we train physicians to perform POCUS? As you can imagine it takes significant training. Our residents meet our POCUS Faculty on day one of their residency for an introductory course. They then receive didactic and practical training throughout their four years of residency.

One of our main educational strategies has recently been presented at a national emergency medicine conference. It has been cited as a comprehensive and efficient way for the practicing physician who has already completed residency training to gain competency. First, Rapid Educational Events are conducted and expose learners to virtual and in-person didactic education. This is coupled with hands-on sessions to reinforce probe positioning and scanning techniques on standardized patients. The final component is participation in Physician Ultrasound Rounds. During these sessions the learner meets one on one with an experienced proctor in the clinical arena. They scan real patients together, honing performance and interpretation skills until a stated number of exams are completed to the satisfaction of the proctor. The exam number to complete is determined by our professional organization, the American College of Emergency Physicians.

The success stories of POCUS in emergency medicine have permeated throughout medicine. Our department has acted as consultants to the military, medical missions, and other specialties both in and outside of our network. We provide education to medical schools, physician assistant programs, and other residencies both within emergency medicine and beyond.

In conclusion, we have found POCUS to be integral in providing state of the art care. When I train residents, I often challenge them with the words “be uncommon” when caring for patients. POCUS truly assists in providing patients with care that is just that, uncommon.