Friday, July 25, 2008
There was a patient with an infected hematoma on his leg. It was pretty disgusting to look at immediately after he took off his bandages. Basically there was a putrid, fleshy black spot on his shin. Dr. Vouyouka had to debride the wound so that it would heal properly, which consisted of surgically removing the dead tissue and irrigating the area. From the patient’s groans and screams—no, he wasn’t put under—the debridement seemed to be an excruciating procedure. Afterwards, gauze was packed into the wound beneath the dermal layer. Moral of the story: take care of your wounds!
In the OR, I saw a thrombectomy that was performed on a woman with a leaky brachial artery in her right arm that resulted in a nasty hematoma. Truthfully, the doctors didn’t really know why her artery was leaky but went and opened her up anyway. I guess they were planning on fixing the artery but found, or maybe even created, a thrombus.
The bloodiest case I saw was a below-the-knee amputation. This was also the most straightforward case I observed during my summer here so far. As you can imagine, Dr. Vouyouka basically cut through all the layers to get to the bone. The bone had to be sawed and any arteries that were cut were tied up. They cut the leg in such a way that the calf muscle was used as a flap to cover everything.
Lastly, I saw a carotid endarterectomy (CEA), which involves the removal of an atherosclerotic plaque from a carotid artery. There are certain complications with this procedure, such as ensuring blood supply to the brain, which is done most often by using a shunt to deliver blood and electroencephalography (EEG) to monitor the brain. To diagnose a stenosed carotid, magnetic resonance angiogram (MRA) or ultrasound is used to determine how much occlusion has developed in the blood vessel.
I wanted to mention
It looks like I should be able to finish my data collection and analyze everything by the end of this term. I’m also excited about going back to
Thursday, July 24, 2008
It has been a long time that doctors found food intake can cause significant increase of portal blood flow, however, fibrous scar and regenerative nodules generated in cirrhosis can severely affect the liver reserve of this flow change. Studies on the comparison of this flow change between normal volunteers and cirrhotic patients by Doppler measurements started about decades ago. But because of the poor accuracy of Doppler in flow measurements, all the previous studies have many discrepancies, rendering this mecomparison not feasible in the diagnosis for early cirrhosis.
On the other hand, MRI can also do the flow measurement using PC (phase contrast) sequence. So Dr. Prince came up with the idea that whether MR can be used to improve the measurement of the portal flow change. Last week, we first tried out this measurement on him before and after meal. Surprisingly, after several repeated scanning, we found the measurement of the same portal flow can be very different in PC. What may cause the measurement error in PC? If we found them out, is it possible that we can get much better measurement of portal flow using MR?
Aiming for discorvering a better non-invasive diagnosis for early cirrhosis, we thought about many parameters that can be modified to achieve the improvement: resolution, SNR, and tricks to make the contour of portal vein, etc. To test these ideas, we need a proper phantom of human portal vein first. Then we came up with the "U-shape tubing phantom" idea. We connected a tubing bended into U shape to the injector of contrast agent and this could work as a nice continous flow phantom mimicing portal vein within 1 minute. Comparing the flow measurement obtained from both "in" and "out" profile of this tubing, we could get an idea about how sensible the scanning method or how accurate the measurement is with the known flow rate in the phantom.
After a whole week fighting with air bubbles, water leakage and all kinds of problems, we have finally got some very useful preliminary data. I am excited about this and will continue to do more measurement this week after analysing the current data thoroughly. I will keep you guys posted on this~
Wednesday, July 23, 2008
A medical student working in Dr. Schwartz's lab took massive amounts of data over the course of two years, stimulating rat brains at various frequencies and analyzing the hemodynamic response. One of the things Dr. Schwartz has asked that I do during my stay at Weill is analyze the data in a meaningful way, so that blood flow response can be correlated with the stimulus. As always in biological, medical, and engineering fields, this task is a little more convoluted than it superficially appears. Firstly, it requires sorting through volumes of data to determine which is "good" and which is "bad." Not to be confused with desirable versus undesirable data, there is actually an issue of noise corrupting some of the data to the point that it is totally unusable. In general, the data can be viewed by the equation: data=gain*truth + bias + noise. I'm trying to cleverly extract the truth from this equation so it can be analyzed. In a perfect world, gain would be 1, and bias and noise would be 0, but I don't expect to be so lucky. Fortunately there is a ton of information on estimation and detection methods, which I can use to hopefully solve this problem.
Tuesday, July 22, 2008
As my summer gets more and more immersed I have begun to really enjoy visiting other surgeon’s ORs. I especially enjoy the mobility that I have been allowed by the plastic surgery department. Over the course of the summer I have seen quite a few breast reconstruction cases because of this mobility. It is quite fascinating to see the different techniques each doctor uses and to see which techniques their residents and fellows have started picking up as they learn. I bring this up because last week I was able to stand in on a surgery with a different doctor than my clinician and see a surgery I have been curious about all summer. I’ve seen quite a few skin grafts and flaps, as well as breast reconstructions post mastectomy with tissue expanders, but it is the TRAM flap surgery that I was really intrigued by.
The TRAM flap, or transverse rectus abdominis myocutaneous flap, is a fairly ingenious way to aesthetically correct a traumatic surgery with a patient’s own tissue. I have had quite a bit of contact with pre-op and post-op mastectomy patients during clinic hours and have heard how difficult the decision is for the method of reconstruction. These patients basically have two choices, the choice of using a tissue expander followed by a permanent implant (silicone or saline, which unto itself is a difficult decision) or the TRAM flap procedure. Both require nipple reconstruction afterward (though a few doctors are now working on nipple saving mastectomies), but the consequences of each are hard to decide between. An implant of course is a synthetic material inside your body, but recovery time is much quicker. The TRAM flap involves taking a large portion of abdominal skin, tissue, and part of the rectus abdominis muscles (in lay terms, your abs), and fashioning a new breast out of that in place of the removed one. This is a much longer surgery, a longer recovery, a lifelong weakening of your abdominal muscles with the increased risk of a hernia and the flap does have the possibility of dying, which in term would lead right back to a tissue expander/implant surgery. Though with the TRAM flap surgery you are replacing your lost breast with your own transplanted tissue and you get a tummy tuck out of the entire process. Seriously not a decision I would want to make, ever.
As I mentioned bore, the patient was not one of Dr. Spector’s patients, but the other surgeon was quite accommodating to let me stay for the 6+ hour operation and attempted to ensure I had a view/knew what was going on. The procedure itself was not a free flap procedure, so in this case the rectus muscle wasn’t cut completely off from the blood supply before being sewn to the tissue above for relocation. This complex, known as the pedicle, was then pushed through a tunnel under the skin made from the abdomen diagonally to the affected side of the chest and sewn into place. After discussing the procedure with Dr. Spector, I found that his preference is actually to perform this as a free flap and actually remove the entire muscle and microsurgically re-establish the blood flow that was feeding the flap. Like I mentioned before, every doctor has their own established way to tackle the same problem. This is why it is important to speak to a few doctors when electing to undergo any surgery. Not every surgeon is the right fit for a patient and the ability to hear new ideas and takes on a situation is important when making an informed choice. Regardless, the surgery was immensely fascinating and seeing this shapeless mass of adipose tissue and skin suddenly come together to form a new breast was astounding. I think it is safe to say I will always be constantly amazed at what doctors have pioneered in surgery.
In the ICU, I experienced two different types of care. Many patients had come in the night before or the day before with an acute symptom (ie nausea, disorientation, shortness of breath). These patients were quickly being moved through diagnosis, treatment and recovery either in the ICU or in another unit of the hospital. Other patients though had more devastating diagnoses which left them in the ICU for a lengthier period of time. Many of these cases were due to the severity of disease or the patients’ inability to breath on their own.
In the Oncology clinic, we visited with patients who had metastasized cancers generally from the bladder, prostate or kidney. Additionally, many of these patients had been through either a surgical procedure to treat their primary cancer site or had undergone chemo or radiation. In general, the patients were visiting Dr. Tagawa in order to alter chemo, enroll in a clinical trial, start hormonal therapy or get general consultation as to what to do next. I was amazed by the variety of patients he saw and how thorough he was with each patient. Each case definitely required customized care and Dr. Tagawa was able to provide not only the standard options for care, but also the numerous clinical trails that were going on under a variety of clinicians.
So now to putting all the puzzle pieces together… My research project with Dr. Scherr is analyzing data from radical robotic cystectomies. Included in the database is detailed information for each patient which allows us to analyze the outcomes with regards to prior surgeries or treatments and complications that occur afterwards. Having looked at this data for a while now, visiting the ICU brought new life to the complications of re-admittance due to sepsis or pneumonia. As well, visiting the Oncology Clinic gave me an idea of what patients go through if their cancer returns. I had visited patients after their cystectomy in Dr. Scherr’s clinic and often the difficulties are with incontinence at night, but the patients in the Oncology Clinic with recurrence deal with many more challenges as they weigh their options for further treatment.
Finally, I’d just like to make a comment about the many roles I’ve seen Dr. Scherr play over the past few weeks. He is both a physician administering personalized care, a surgeon with technical skills, a researcher always asking questions and even an entrepreneur looking for new developments to change the way treatment in administered. I’ve been amazed to see him put on these different “hats” and even more astonished to see just how well each one fits.