Point-of-care ultrasound (POCUS) is a useful, practice-changing bedside tool that spans all medical and surgical specialties. While the definition of POCUS varies, most would agree it is an abbreviated exam that helps to answer a specific clinical question. With the expansion of POCUS training, the clinical questions being asked and answered have increased in scope and volume. The types of exams being utilized in “point of care ultrasound” have also increased and include transthoracic echocardiography; trans-esophageal echocardiography; and lung, gastric, abdominal, and ocular ultrasound. POCUS is used across multiple specialties, including critical care, anesthesiology, emergency medicine, and primary care.
CHEST
Dr. Nicholas Villalobos
Not only has POCUS become increasingly important clinically, but specialties now test these skills on their respective board examinations. Anesthesia is one of many such examples. The content outline for the American Board of Anesthesiology includes POCUS as a tested item on both the written and applied components of the exam. POCUS training must be directed toward both optimizing patient management and preparing learners for their board examination. A method for teaching this has yet to be defined (Naji A, et al. Cureus. 2021;13[5]:e15217).
One question – how should different specialties approach this educational challenge and should specialties train together? The answer is complicated. Many POCUS courses and certifications exist, and all vary in their content, didactics, and length. No true gold standard exists for POCUS certification for radiology or noncardiology providers. Additionally, there are no defined expectations or testing processes that certify a provider is “certified” to perform POCUS. While waiting for medical society guidelines to address these issues, many in graduate medical education (GME) are coming up with their own ways to incorporate POCUS into their respective training programs (Atkinson P, et al. CJEM. 2015 Mar;17[2]:161).
Who’s training whom?
Over the past decade, several expert committees, including those in critical care, have developed recommendations and consensus statements urging training facilities to independently create POCUS curriculums. The threshold for many programs to enter this realm of expertise is high and oftentimes unobtainable. We’ve seen emergency medicine and anesthesia raise the bar for ultrasound education in their residencies, but it’s unclear whether all fellowship-trained physicians can and should be tasked with obtaining official POCUS certification.
While specific specialties may require tailored certifications, there’s a considerable overlap in POCUS exam content across specialties. One approach to POCUS training could be developing and implementing a multidisciplinary curriculum. This would allow for pooling of resources (equipment, staff) and harnessing knowledge from providers familiar with different phases of patient care (ICU, perioperative, ED, outpatient clinics). By approaching POCUS from a multidisciplinary perspective, the quality of education may be enhanced (Mayo PH, et al. Intensive Care Med. 2014;40[5]:654). Is it then prudent for providers and trainees alike to share in didactics across all areas of the hospital and clinic? Would this close the knowledge gap between specialties who are facile with ultrasound and those not?
Determining the role of transesophageal echocardiography in a POCUS curriculum
This modality of imaging has been, until recently, reserved for cardiologists and anesthesiologists. More recently transesophageal echocardiography (TEE) has been utilized by emergency and critical care medicine physicians. TEE is part of recommended training for these specialties as a tool for diagnostic and rescue measures, including ventilator management, emergency procedures, and medication titration. Rescue TEE can also be utilized perioperatively where the transthoracic exam is limited by poor windows or the operative procedure precludes access to the chest. While transthoracic echocardiography (TTE) is often used in a point of care fashion, TEE is utilized less often. This may stem from the invasive nature of the procedure but likely also results from lack of equipment and training. Like POCUS overall, TEE POCUS will require incorporation into training programs to achieve widespread use and acceptance.
A deluge of research on TEE for the noncardiologist shows this modality is minimally invasive, safe, and effective. As it becomes more readily available and technology improves, there is no reason why an esophageal probe can’t be used in a patient with a secured airway (Wray TC, et al. J Intensive Care Med. 2021;36[1]:123).
Ultrasound for hemodynamic monitoring
There are many methods employed for hemodynamic monitoring in the ICU. Although echocardiographic and vascular parameters have been validated in the cardiac and perioperative fields, their application in the ICU setting for resuscitation and volume management remain somewhat controversial. The use of TEE and more advanced understanding of spectral doppler and pulmonary ultrasonography using TEE has revolutionized the way providers are managing critically ill patients. (Garcia YA, et al. Chest. 2017;152[4]:736).
In our opinion, physiology and imaging training for residents and fellows should be required for critical care medicine trainees. Delving into the nuances of frank-starling curves, stroke work, and diastolic function will enrich their understanding and highlight the applicability of ultrasonography. Furthermore, all clinicians caring for patients with critical illness should be privy to the nuances of physiologic derangement, and to that end, advanced echocardiographic principles and image acquisition. The heart-lung interactions are demonstrated in real time using POCUS and can clearly delineate treatment goals (Vieillard-Baron A, et al. Intensive Care Med. 2019;45[6]:770).
Documentation and billing
If clinicians are making medical decisions based off imaging gathered at the bedside and interpreted in real-time, documentation should reflect that. That documentation will invariably lead to billing and possibly audit or quality review by colleagues or other healthcare staff. Radiology and cardiology have perfected the billing process for image interpretation, but their form of documentation and interpretation may not easily be implemented in the perioperative or critical care settings. An abbreviated document with focused information should take the place of the formal study. With that, the credentialing and board certification process will allow providers to feel empowered to make clinical decisions based off these focused examinations.
Dr. Goertzen is Chief Fellow, Pulmonary/Critical Care; Dr. Knuf is Program Director, Department of Anesthesia; and Dr. Villalobos is Director of Medical ICU, Department of Internal Medicine, San Antonio Military Medical Center, San Antonio, Texas.