How Relevant Is Point-of-Care Ultrasound in LMIC?

The trajectory of medical ultrasound has beenmarked by quantum decreases in size. In the 1950s, the first ultrasounds were performed using refrigerator-sized machines, with patients subjected to water immersion. Adoption of this technology across many medical specialties was hindered by machine bulk and cost, low-resolution still images, and a steep learning curve for image interpretation. Incremental changes in ultrasound technology through the 1970s and 1980s allowed machines to be moved on wheels, and eventually to sit atop a cart. It was not until the 1990s that an ultrasound machine capable of being transported in a backpack was invented, as a result of a Defense Advanced Research Projects Agency (DARPA) grant. As with other computer technology, ultrasound machines then rapidly grew smaller and more powerful, and a wider user base began adopting them for multiple types of medical applications. By the 1990s, portable ultrasound machines were deployed in combat support hospitals, ambulances, helicopters, and a host of austere environments. Researchers described experiences using ultrasound on medical missions in remote Amazon jungle settlements, high-altitude environments in Nepal’s Himalayan Rescue Association Clinic, and the International Space Station. A report from Guatemala in the aftermath of Hurricane Stan demonstrated that point-ofcare ultrasound confirmed or ruled out emergent pathology in almost half of subjects evaluated. During the disaster relief effort following the 2010 Haitian earthquake, point-of-care ultrasound helped clinicians change management in 70% of cases, with nearly half of those decisions based on acute pathology identified examination. On the basis of experiences such as these, the World Health Organization recommends increased use of ultrasound as a main diagnostic modality, especially in underresourced environments. Ultrasound machine costs are generally lower than x-ray or computed tomography scan capital expenses, and ultrasound requires very little ongoing cost for consumables (such as gel), compared to the ongoing upkeep costs of these other modalities. Increasingly, ultrasound is being used in areaswithout easy access to imaging of any kind. Clinicians in the Lugufo refugee camp in Tanzania identifiedmany tropical infectious disease manifestations on ultrasound. Midwives in rural Rwanda, Zambia, and Liberia have been trained in the use of focused obstetric ultrasound with the goal of identifying common and life-threatening complications of late pregnancy. In areas where maternal and fetal mortality are significant health concerns, accurate pregnancy dating, early identification of breech presentation, and proper placental position could significantly impact the care provided and save lives. Advances in telemedicine have enabled expansion in ultrasound use as well. Recently, health care workers in rural India underwent training in basic cardiac and thoracic ultrasound with the goal of transmitting images to physicians at major hospital centers for real-time interpretation. Ultrasound has been described as a disruptive innovation byHarvard professor ClaytonM.Christensen. The term, originally coined by Christensen in reference to disk drives, refers to an innovation that transforms a market “by introducing simplicity, convenience, accessibility, and affordability where complication and high cost are the status quo.” Often, such innovations take the form of a narrow, niche market, overlooked by industry leaders, but as new users take hold, the new product can claim significant market share. In the case of ultrasound, traditional imagers such as radiologists, obstetricians, and cardiologists controlled a market marked by expensive, immobile machines whose images could only be interpreted by highly trained subspecialists within their respective fields. Hand-held ultrasound devices introduced an alternative concept of relatively inexpensive, easy-to-use machines that could generate images interpretable by a wider spectrum of clinicians at the point of care. Soon, concerns about smaller machines having inferior image quality compared to devicesmany times larger andmore expensive were outweighed by evidence that rapid diagnostic decisions could be made with portable machines. In the 1990s, emergencymedicine physicians joined the ranks of clinician-sonographers and described ultrasound training as part of the core competencies for residency training in 1994. Surgeons used ultrasound for trauma at this time as well. A wave of intensivists, ophthalmologists, internists, and other specialists found utility in point-of-care ultrasound by the 2000s, and a 2011 article in the New England Journal of Medicine by Moore and Copel listed 24 specialties who had adopted the technology into common clinical practice. In 2013, the Agency for Healthcare Research and Quality published “Making Health Care Safer II,” an update of its previous 2001 guidelines for best practices in patient safety. Among the top 10 practices in both publications was using ultrasound to guide central venous access. With mounting evidence that iatrogenic complications of many invasive procedures such as venous access, thoracentesis, paracentesis, and others can be mitigated with point-of-care ultrasound, hospitals are increasingly mandating training in ultrasound by clinicians. As of this writing, a number of medical schools have adopted ultrasound curricula as well, incorporating sonographic assessments of multiple organ systems along with traditional courses on physical examination and clinical reasoning. Many authors have argued that ultrasound has become the stethoscope of the 21st century. Why then, do we not see The authors report no relationships that could be construed as a conflict of interest. From the *Department of Emergency Medicine and yDepartment of Cardiology, Icahn School of Medicine at Mount Sinai, New York, NY, USA. Correspondence: J. Narula (Narula@ mountsinai.org).