Monday, February 13, 2012
Seeing into the human heart--Valentine's Day and the GE V-scan pocket ultrasound
I am presently a fan of the human heart. After going to a short ultrasound course put on by the Department of Emergency Medicine at Harvard Medical School in November, I have been intrigued by the possibility of making ultrasound imaging a routine part of a physical exam, since it is harmless and uses no resources. When I got back from Harvard, I borrowed the small portable ultrasound machine in our hospital and ultrasounded everyone who would hold still when my working day was not too busy. The machine was inconveniently located in radiology and took awhile to get upstairs, but I still used it pretty frequently. I started out self conscious and inept and gradually began to be able to use the transducer in such a way that I could obtain images of the structures I was interested in, some or most of the time. In the first 3 weeks after the course I probably did 20 ultrasounds, with many disclaimers to the patients that I was just practicing and didn't really know what I was doing. They were nevertheless interested, and I found that the extra time I spent with them lead to more in depth sharing of stories and the images that I could get helped with diagnosis and treatment.
At the Harvard course there were lots of device sales people hawking their expensive machines, and one of them was a woman from General Electric who had a really little machine, small enough to go in a coat pocket, which gave pictures almost as good as the big machines. After dragging the portable but definitely not pocket size machine around our hospital for a couple of months, I decided that I needed to buy this pocket sized gizmo. I searched for deals online and found that there were many options, but that for what I wanted, small size and good picture, the GE machine was it. Siemens makes a nice slightly larger and slightly more expensive machine and a company out of Seattle makes a machine that uses an iPhone as its interface. This was intriguing, but I heard the pictures were just too small. I also found that farmers and veterinarians use ultrasounds and that theirs are much cheaper and would be perfect except that the transducer is shaped to go in an animal's rectum to image pregnancy and would not be what I would need for looking at people from the surface. The cost of the GE V-scan was nearly $9000, which only looked good in comparison to the larger models which are the size of a laptop and cost upwards of $50,000. I thought of how some rich hospital should maybe buy the pocket ultrasound for me, and realized that without having it and using it to know its utility, there would be no way to convince anyone to buy me one. I rationalized that I had not bought myself a new car since 1992 and didn't intend to anytime soon. I then shelled out the bucks. To buy this, I had to prove that I was a real physician and it was shipped to my work rather than home. I'm not sure who this was supposed to protect, but that's how it was.
Since buying my ultrasound I have begun to use it routinely, much as I would my stethoscope, but with greater confidence and it is incredibly helpful to determine whether a person has congestive heart failure, whether they are short of breath from a weak heart or from infection, whether they need more or less salt and water. I can also identify enlarged livers or spleens and can see if a bladder is full. With more training, which I will eagerly get in the next few months, it will become even more useful. There are so many decisions that I can make more confidently knowing what the insides of an individual look like, especially the heart.
The heart. The human heart is the most amazing thing. It is not hard to see why it has taken such an important place in art and literature. During medical school I looked at still pictures of the heart and dissected dead hearts and photos of x-rays of hearts and even the occasional ultrasound image. We learned how the blood flowed--from the body to the central veins, the inferior and superior vena cava, to the right atrium and then right ventricle, out to the lungs, then back, oxygenated, to the left atrium and ventricle, then out via the aorta to serve the body. But there is just nothing like looking at the heart in real time. Ultrasound allows you to tour the human heart, look at it from all sorts of angles, and though the picture is 2 dimensional, the myriad views I have allow me to perceive it in 3 dimensions.
The left side of the heart is the larger of the two sides and gets most of the attention. I am presently intrigued with the right side, though. The right side is not as strong a muscle as the left side, because the resistance in the blood vessels of the body is higher that the resistance in the lungs (except in severe pulmonary hypertension, which is a very bad disease.) But the right heart looks different from the left in a way that is utterly awe inspiring. The right heart dances. At least it does when it's healthy. The ventricle, which is more muscular than the atrium, pumps blood out, and as it does its contraction acts to pull blood into the right atrium from the great veins. They never told me that in medical school, but when I look at it, the process is absolutely clear. And when the atrium contracts to send blood into the ventricle, this thin walled structure appears to wink, as fast as an eye. It is totally cool to watch.
From the fact that I am able to get useful information from my little machine after very little training (though lots of practice) it is clear to me that this will become much more common and it will reduce the need for various blood tests which represent the state of health or disease of our innards much less accurately. Already emergency department residents are required to have a certain level of ultrasound competence to complete their programs. This will become standard in other specialties as the technology becomes cheaper and easier to use. I hope this new generation of physicians will search for the ways in which routine use of imaging can streamline diagnosis and spur useful conversations between doctors and patients. I hope they will also continue to be awed by the ability to see the inner workings of peoples' bodies.