This Fox Hunts with Ultrasound
This school year, UC Irvine has become one of the first medical schools in the nation to integrate portable ultrasound training into its curriculum.
The program is headed by Dr. Chris Fox, director of emergency ultrasound and associate professor of clinical emergency medicine at UCI. He has been working in emergency medicine for about 10 years. For a few years, Dr. Fox taught an elective course for fourth-year medical students that revolved around using ultrasound to diagnose. He began receiving calls from many of his students relaying how they diagnosed a patient or how the skills they learned in his class were important during their residency.
Dr. Fox knew he wanted to develop a curriculum to incorporate this in all four years of a medical student’s study. So he sought out Kevin Goodwin, the president of SonoSite, which is a company that specializes in “hand-carried and mountable ultrasound.”
“I met with him and he was very interested in providing us with the necessary equipment,” Fox said.
Currently, only first and second-year medical students are training in portable ultrasound. Dr. Fox’s syllabus has first-years getting comfortable with the machine. They are just beginning to learn about anatomy, physiology and biochemistry, and Dr. Fox hopes that they will also be able to understand the physics, depth, frequency and operation of the device. He wants students to know how to optimize the image and to differentiate between the skin, muscle, bone, nerve and organs on the portable machine’s screen.
“It’s really exciting to be able to see people’s organs right away,” said Sarah Cousins, a first-year medical student, who often uses the device. “I mean, I haven’t even taken anatomy yet, but Dr. Fox tells us where to look. We’ve seen hearts beating and everything. It is kind of weird to be touching people even if they’re not our real patients, but it’s cool.”
Second-years are shown 100 typical cases, something Dr. Fox refers to as “pathological cases.” Students are able to get a hands-on approach to these cases, which include ectopic pregnancies and gallstones.
Every student receives regular instruction and has access to the device in curriculum, during workshops and even after hours in the student lounge.
“It works best when a person is lying down so we practice on our friends in the lounge,” Cousins said. “We just look around until we find something interesting.”
Because the cost of a portable ultrasound is about the same as an upscale car, Dr. Fox has just enough so that “every medical student has direct one-on-one exposure with the machines and patients,” and he choreographs the locations of the devices to ensure that this is possible.
“The plan is to have all four years of the curriculum use the portable ultrasound,” Fox said. “There is a very aggressive projected timeline and we are in the process of developing third-year modules. It should be possible by July 2011 to get these incorporated for third-year students.”
One of the major advantages of a portable ultrasound is that it involves no radiation.
There are four modalities doctors use: x-rays, CT scans, MRIs and ultrasound. The amount of radiation exposure involved in a CT scan of a person’s abdominal region is equivalent to 500 chest x-rays. An ultrasound device uses none.
“If we can avoid the need to get a CT scan, then patients would be much safer,” Fox said. “The accumulation of radiation over time can lead to cancer so it can be risky. With ultrasound, there is no radiation and there are no biohazard risks.”
Another benefit of the portable ultrasound is its convenience – it is hand-held and can be used at the “point of care,” or right at the patient’s bedside.
Also, the cost for the patient is much cheaper. While CT scans typically cost around $1,000 to $1,200, an ultrasound may cost $30.
A minor reported disadvantage to the portable ultrasound is the necessity to recharge. The machine relies on a rechargeable battery and, if there is no plug nearby, the battery life only lasts two hours.
Another drawback is investigating parts of the body with air. Structures that have a lot of air around them do not show up on the screen and doctors must therefore turn to the CT scan. For example, Dr. Fox is not able to use the portable ultrasound to see past the lung to the esophagus or thoracic aorta.
On the sports field, the portable ultrasound is used in the NBA and NFL to immediately identify injuries like fractures, dislocations and joint fluid. In the hospital, Dr. Fox has used it to diagnose pneumonia, collapsed lungs, fluid buildup in the lung, chest or heart, thickening of the heart’s valves, aneurysms, blood clots, liver blockage, pancreatic fluid collections, enlarged spleens, kidney blockage and bladder functionality, just to name a few.
“People think that ultrasound is just for babies,” Fox said. “That is probably the most offensive thing to say to me. Ultrasound can be used to verify normal pregnancies, but it can also diagnose ectopic pregnancies, as well as infections in the skin, pelvis, gallbladder, everywhere.”
If a patient is in critical condition, the ultrasound can be used as the definitive diagnostic test. However, if the patient is stable, doctors sometimes follow the diagnosis up with a traditional cart-based confirmatory test just to be sure.
Although it is not used during a regular check-up, Fox believes that the portable ultrasound will someday be a part of every clinician’s physical exam. When a patient says he has belly pain, explained Fox, the doctor must run through all the organs associated with the abdomen in his head.
“The test characteristics of a physical exam are very poor,” Fox said. “Ultrasound is a revolutionary leg up on that. Now, if a patient has belly pain, I can just use ultrasound to visually see it on the screen.”
In the future, Fox believes we can look to see further advances in diagnostic imaging. There are cursory developments for a portable MRI, but, because MRIs involve a giant magnet, hand-held devices seem unlikely.
Ultrasound wireless probes, on the other hand, seem within our reach. Fox projects that he will soon be able to wirelessly stream the images to a cell phone or even projected on the patient as a hologram. He also predicts 3-D portable ultrasound devices to be integrated within hospitals soon.
“On the front end, seeing how excited medical students become when they see the anatomy and physiology of a body within pictures of a textbook actually come to life on a screen is my favorite part of all of this,” Fox said. “All they can say is, ‘Wow.’ On the back end, it’s patient outcomes. The feeling of learning that a student I taught saved a person’s life with ultrasound is indescribable.”