Thursday, September 18, 2014
Emergency room doctors can safely use bedside ultrasound to diagnose kidney stones, saving billions of dollars and preventing some radiation induced cancers
An article came out just recently in the New England Journal of Medicine, which has a large circulation and should make a bit of a splash. This multi-center study looked at the option of having patients (excluding the very obese, pregnant and critically ill) with abdominal and flank pain suspected of having kidney stones evaluated first by emergency physicians with ultrasound of the kidneys and bladder before considering getting a CT scan. Normally a patient with suspected kidney stones (crampy pain in the back or abdomen, blood in the urine, suggestive history) will be referred for an abdominal and pelvic CT scan, which costs over $3000 and carries a significant amount of radiation exposure. In perfect circumstances performing the test and getting the results takes an hour, but it can end up taking several hours due to the usual delays. Sometimes patients with kidney stone type symptoms are referred by the emergency physician for an ultrasound by the radiology department, which takes about the same amount of time as the CT which takes the same amount of time, but costs a bit less and delivers no ionizing radiation. CT scans have beautiful pictures and can often find the kidney stone, if it's in there, and not finding the stone is strongly suggestive that the diagnosis of what is causing the pain must be sought elsewhere. Ultrasound can show if the kidney is blocked by showing lack of flow into the bladder or buildup of fluid in the kidney (hydronephrosis) but rarely actually visualizes the stone. This information, however, is adequate to make the diagnosis in most cases, when combined with a good clinical history, physical exam and lab tests.
It turns out that the bedside ultrasound exam done by emergency room docs (in this study they were from multiple medical centers including University of California at San Francisco, Cook County and Rush Medical Centers in Chicago, Group Health in Seattle and many more high quality locations) is adequate in cases of abdominal or flank pain as a first evaluation to rule in or out kidney stones. It is much more focused than an ultrasound performed by the radiology department and it only takes about 5 minutes or less to perform. Since it is done by the physician examining the patient it is also a time to take more history and do more general observation, which is always a good thing. About 40% of the patients initially evaluated this way got an official radiology ultrasound or CT scan which were felt to be necessary by the ER physician to clarify what was going on. About a million patients with kidney stones visit emergency rooms each year in the US and more than 10 times that many visit ER's with symptoms that sound a bit like kidney stones and have to be evaluated for them. If all of them got bedside ultrasound as the initial evaluation of their kidneys, my back-of-the-envelope calculations suggest that multiple billions of dollars could be saved on imaging costs and lives could potentially be saved due to reduced radiation exposure. The study showed no significant increase in complications in the patients first receiving bedside ultrasound. Actual cost savings were calculated, but not reported in the study (why?)
We can't just start doing this because not all ER doctors are yet comfortable performing and interpreting bedside ultrasound of the kidneys and bladder. But they could be. It is not hard. Pretty much anybody could learn to do this in maybe an hour and could certainly be competent after doing 50 exams. The implications of this are bigger than the article points out. When ER physicians start doing regular bedside (or "point of care" as it's sometimes termed) ultrasound they are going to get better at it. They will start to use ultrasound more and develop some pattern recognition skills that can't be predicted which will likely lead to more accurate diagnoses of other diseases, and possibly less dependence on ionizing and expensive radiation in the form of CT scans.
Unfortunately CT scans for abdominal pain in the emergency room are an important source of revenue for both radiologists and hospitals which puts a little kink in the clear path toward adopting bedside ultrasound as a diagnostic procedure of choice. It's not clear what to do with this, because we could surely use the expertise of radiologists and radiology technicians in training physicians to be good bedside ultrasonographers and presently that would be a pretty big conflict of interest for them. Still, there is so much good stuff going on in the field of high tech ultrasound that is not in the scope of bedside ultrasound that radiologists and technicians could be kept gainfully occupied by doing things that other physicians can't and shouldn't do. In the journal of the American Institute of Ultrasound in Medicine there were several articles about amazing and technically challenging imaging applications that non-radiologists might be wise not to try. There were articles about ultrasound of the midbrain to evaluate Parkinson's Disease, ultrasound of the liver to look at severity of cirrhosis, ultrasound of children with intestinal intussusception (telescoping of the bowel) to follow the success of noninvasive treatments and detailed prenatal evaluations for conditions I didn't even know existed. Ultrasound to diagnose appendicitis has become nearly standard now, but is really hard to learn and ultrasonographers and radiologists do it well (some ER physicians do it well too, but it's far from an entry level skill.) Looking at the kidneys in 5 minutes in the ER is clearly fine for evaluating possible kidney stones. An abdominal ultrasound in the radiology department with their big powerful machine with the gorgeous images combined with the stunning command of anatomy of radiology professionals is a different and differently beneficial thing. This recent article may help move us as hospitalists, ER physicians and primary care providers toward doing more bedside ultrasound, which could be a very good thing. Perhaps more radiologists will find peace with that and can bring themselves to help teach other medical staff who need to learn how to do it.