The contribution of physicists and physics research has paved the way for many technological breakthroughs within the past two centuries. Radar, cellular phones, the internet, MRI, and even the discovery of the structure of DNA are attributable to physicists and their research. (Had it not been for a WWII bomb destroying the physics laboratory and experiments of Dr. Francis Crick, a physicist, he would not have ventured into biology and later helped discover the structure of DNA!)
Diagnostic ultrasound is a product of physics extending into medical applications. Originally, sound propagation was being refined for military purposes, such as detecting submarines and vessels at sea by way of SONAR (Med Phys Int 2021;Special Issue:469-98). Increasing the sound frequency from kilohertz to megahertz while reducing the pulse-echo wave transit time from milliseconds to microseconds allowed sound to diagnose millimeter flaws in metal ship hulls. This “metal flaw detector” would later be used by Dr. Ian Donald, a Royal Air Force Veteran of WWII familiar with its use in the military, to examine fibroid and ovarian cyst specimens in the laboratory (Surg Clin North Am 1998;78:179-95). Through successive refinements and new modalities came real-time, high-resolution images and increased diagnostic functionality like a continuous wave and color flow Doppler.
Today, diagnostic ultrasound has evolved into point-of-care ultrasound (POCUS), with clinical applications ranging from volume status to detection of respiratory pathology. We will briefly touch on some of the clinical applications, the future, and the utility/advocacy of POCUS to the specialty of anesthesiology.
POCUS has long been a valuable tool for anesthesiologists in invasive procedures and regional techniques. However, it has many other potential uses in diagnosing and managing perioperative complications. POCUS is accurate, reliable, and easy to use, and smaller machines attached to handheld devices provide flexibility in care.
Anesthesiologists use POCUS to evaluate and manage patients undergoing anesthesia and to diagnose and manage perioperative complications. POCUS is portable and readily available, allowing for rapid assessment of critical patients. It can assess cardiac function, hemodynamics, and complications such as pneumothorax, pleural effusions, or cardiac tamponade (Curr Pain Headache Rep 2020;24:20). It can be used to evaluate gastric volume, reducing aspiration risk. POCUS also aids postoperative management by diagnosing and managing complications, as above. Recent focus has been on using POCUS to assess venous congestion. This modality has been used by liver and kidney specialists to evaluate congestion in those organs. One is sure to see the increasing use of venous Doppler not only to aid resuscitation but also to help de-resuscitate the patient. The size, cost, and availability further ease the use of ultrasound in increasingly austere and resource-limited regions where diagnostic imagery is limited. Our emergency medicine colleagues have even initiated austere POCUS fellowships whereby application in a resource-limited environment often impacts clinical decision-making (Ultrasound J 2020;12:14). As POCUS undeniably aids in qualifying the etiology of shock, it is unsurprising that our military colleagues increasingly employ ultrasound technology to move health care delivery closer and closer to the point of injury.
This essential perioperative tool aids with procedures, helps with diagnosing certain conditions, acts as an extension to the physical exam, and helps monitor treatments. It has the distinct advantage of being lightweight and easily accessible, allowing for rapid assessment of critically ill patients. As technology advances and AI becomes more prevalent in medicine, the role of POCUS in anesthesiology will expand even further.
Corresponding with this exponential growth in ultrasound application by non-radiologists/non-sonologists is an explosion of research leading to the development of increasingly complex protocols for point-of-care application. As radiologists/sonologists receive significant ultrasound application and interpretation training, new questions arise, requiring focus on the best way to teach POCUS. Investigation into the use of virtual reality and motion metric feedback is ongoing. Recognizing skillset limitations, further attention is given to a telemedicine capability whereby providers transmit real-time ultrasound images and seek specialist feedback. AI technology investigation is also ongoing (Ultrasound Med Biol 2023;49:178-85; J Spec Oper Med 2023;23:67-73; Ultrasound J 2020;12:33). Imagine finding yourself on call in a small community hospital in the middle of the night, or on a plane, or a ship, with an ultrasound probe and a handheld device (Circ Cardiovasc Imaging 2019;12:e009303). You connect your device to a network and transmit your ultrasound images to a team of physicians (i.e., intensivists, cardiologists, traumatologists, radiologists), or AI, that can supply instantaneous feedback to optimize the care of your patient.
As the acceptance of POCUS grows in our specialty, we must address issues pertaining to implementation, privileging, credentialing, certification, quality, and billing. Various organizations provide POCUS/ultrasound certifications, and working on one of these certifications starts with one’s POCUS journey (asamonitor.pub/44RS3lw; asamonitor.pub/44wZfDN; asamonitor.pub/44I1ILq). Advocacy for POCUS is needed locally and nationally. Anesthesiology societies that are leaders in POCUS, like ASA, ASRA, SCA, SOCCA, and SATA, should continue to build on the existing structure and push for more innovation in POCUS. Over the past few years, the American Board of Anesthesiology has incorporated POCUS testing for anesthesiology certification. The only way forward is to incorporate POCUS in our daily practice. Our goal should be to ensure that the future anesthesiologist is a leader in POCUS and continues to expand its use. POCUS is where transesophageal echocardiography was in cardiac anesthesiology in the 1980s and ’90s. Cardiac anesthesiologists are now leaders in TEE. We have done this before and can repeat it with POCUS. Who better than anesthesiologists to take POCUS to the next level?