By: Adam Siegel, MS4 Zucker SOM @ Hofstra/Northwell
Point-of-Care Ultrasound (POCUS) is an emerging trend in many healthcare settings. While conventional diagnostic ultrasound examinations are ordered by a primary physician, performed by a radiologist or technician and then interpreted by a radiologist, POCUS examinations are both performed and interpreted by the physician at the patient’s bedside. The nature of ultrasound as an imaging modality lends itself well to being performed at the point of care: it is low cost, non-invasive, real-time, and with no ionizing radiation. As such, POCUS is being adopted by a number of physicians from various specialties, and is even being integrated into the training of residents and medical students at some institutions.
POCUS not only allows for bedside diagnostic ultrasound, but also can be used for bedside therapeutic ultrasound procedures. Procedures like paracentesis, thoracentesis, peripheral vascular access, and others can be performed in either the interventional suite by an interventional radiologist, or at the patient’s bedside by their primary physician using a point-of-care ultrasound setup. As more physicians are trained in point-of-care ultrasound interventions, the role of the interventional radiologist in bedside procedures will need to be evaluated. As it stands, the expertise of an interventional radiologist is best suited to complex vascular and non-vascular cases beyond the scope of POCUS, however many interventional radiologists are expected to perform simpler bedside procedures as part of their day-to-day work. It is imperative that IR physicians and trainees understand the role of POCUS and bedside ultrasound guided procedures within the healthcare system.
POCUS uses the non-invasive and accessible nature of ultrasound to its advantage, allowing providers from a number of specialties and training levels to become credentialed. While a full ultrasound examination is left to radiologists, POCUS credentialed providers use a more clinically focused approach. For example, while a radiology scan for DVT is extensive and utilizes Doppler and compressibility at multiple specific sites along the deep leg veins, a POCUS scan generally only utilizes compressibility of the vein at specific sites (Femoral vein, SFJ, Popliteal vein and trifurcation, etc) with obvious visualized thrombus being assessed as well. The more clinically focused nature of POCUS allows providers from many specialties (Emergency medicine, rheumatology, family medicine) to use ultrasound to guide their clinical judgment and treatment strategy. POCUS is not also limited to physicians: PAs and NPs may be trained to perform exams and do procedures, and RNs may be trained to use ultrasound for vascular access.
The typical POCUS equipment is more portable than a radiologist’s ultrasound setup. POCUS machines are designed with portability in mind and typically have a smaller footprint and smaller screen than those found in the radiology suite. While these machines may lack some of the advanced functionality of bigger machines, they offer the same basic probe types and similar major functions (M-mode, Doppler, etc). Most exciting is the advent of tablet-based POCUS probes (Philips Lumify, Butterfly iQ), which require only a tablet or phone to use and can take surprisingly high quality images. While these devices aren’t typically within the radiologist’s wheelhouse, they offer unparalleled ease of use and accessibility, and can be used with bedside procedures.
So where does the interventional radiologist play into this paradigm? It is important for the IR provider to know what procedures can be done using POCUS, and what needs to be done in a more formal IR suite setting. In the Emergency room and ICU, ED providers commonly use POCUS to place peripheral IV lines in patients with difficult veins, as well as during central line placement in critically ill patients. POCUS can also be used for diagnostic and therapeutic drainage (thoracentesis, paracentesis); given the large amount of fluid and relatively forgiving anatomy, drains placed using POCUS typically do not require the skill of an interventionalist, however these procedures are of course not without risk themselves. Many joint procedures lend themselves well to POCUS, including arthrocentesis and joint injections, and rheumatologists can use POCUS in their outpatient practices.
POCUS is becoming a required part of the curriculum in many residency programs and medical schools. My own medical school, Zucker School of Medicine at Hofstra/Northwell in New York, features POCUS as an integral part of the MS1 and MS2 curriculum, with the option for further training as an MS4. Ultrasound rotations are integrated into some emergency medicine residency programs, and ultrasound fellowships are available in EM. With the push to train more providers in POCUS, there will be more push to take simple procedures out of the radiology suite and bring them to the bedside. More complex procedures like biopsy and difficult vascular access will require an interventionalist’s expertise, but it is imperative that the IR physicians understand the scope and limitations of POCUS procedures so that patients get the best case possible.