Friday, June 29, 2007
RCTs have a lot of merit in clinical treatment trials, however, they do not seem to be very informative and efficient as far as screening is concerned. I am simplifying so much here but what I just said seems to be the matter of controversy in the medical community. In the 1970's three RCTs, Mayo Lung Project (MLP), Memorial Sloan-Kettering Lung Project (MSKLP), and Johns Hopkins Lung Project (JHLP) looked at the effect of screening people with a high risk of developing lung cancer with chest radiograph (CXR) and sputum cytology. The MLP (the largest of all three and funded by NCI) after 6 years of screening and about 14 years of follow up, concluded that screening with CXR does improve the survival but does not reduce mortality rate compared to the controled groups. In other words, CXR may be detecting a lot of biologically cancerous, but clinically benign cases that will improve the survival but it is not actually saving lives and that's why the difference in mortality between the two groups did not turn out significant. This result was followed by same results from MSKLP and JHLP. As a result mass screening for lung cancer, at least for individuals with high risk of developing it did not turn into public policy (as opposed to other cancers screenings such as breast cancer or cervical cancer).
So here is the question: it makes intuitive sense that the sooner you catch cancer, the better your chances of treating it. So why the the above RCTs prove the opposite? It's also worth mentioning that a few years ago the same controversy was involved in questioning the merits of annual mamography for women to screen for breast cancer. In this case again a few RCTs disprove the value of mamography screening while a lot of clinicians disagreed with the results. So where's the mystery? What seems to be inconsistent here? stay tuned.......:)
The patient has a stenosis in one of his arteries; therefore, an angioplasty procedure is followed. A typical stenosis region is as shown in the left image above (red arrow). It appears as a sudden narrowing of the blood vessels. After looking at the stenosis or blockage area, the physician asked one of his assistant to get a stent and balloon. Then, he uses a guidewire (basically a very thin wire that fits inside the catheter) to guide the stent through the catheter to the area of blockage and placed the stent there. Next, he uses the guidewire again to direct the balloon in place. Then the physician inflated the balloon, so it crushed the plaque and expand the vessels. Finally, he checks the x-ray to make sure the stenosis is no longer there.
Interestingly, a woman who is not a medical staff always walks back and forth between different catheter labs. After talking with a fellow student in the lab, I found out that she is actually from
Now I have seen many great things~Open Brain Surgery~Busted Aneurysms~Open Heart Surgery~Tendon/rotator cuff reconstruction. But nothing has compared to my 2 am visit to the ER after going out to a nice dinner!
The ER was cluttered with Manhattans elite; drunk CEO's with broken bones, as well as the not so fortunate stab wounded victims from a large street brawl. I was lucky that I went with my scrubs on, since it was hard to distinguish hospital-people in hustle and bustle.
Thursday, June 28, 2007
The next day, I observed an endoscopic removal of a tumor through the nasal cavity. The operation consisted of the entire removal of the pituitary gland, which the tumor had infiltrated. The entire surgery took about 7 hours. It was amazing to see how much the doctors were capable of doing despite the size of the tools and how little degrees of freedom they had. Later that week, I saw a removal of the lesion (possible tumor) in the temporal lobe in one patient and the removal of the amygdala and hippocampus in another. I observed a clinical experience in which electrodes were used to stimulate and record electrical activity of the epileptic tissue. As a part of my project, I wll be analyzing some of the clinical data, which should be very interesting.
This week has been just as interesting. Monday there was a case in which the patient had to be kept awake while the brain tumor (near the motor cortex) was being removed. The doctors had to make sure they did not commit any collateral damage to the brain. I also observed a patient that had surface and depth electrodes implanted into the brain. I believe they will be used to monitor his brain activity to hopefully map the focal point of the seizures.
It has been a great two weeks so far, and I expect it to get even better.
Wednesday, June 27, 2007
Every Monday morning at 7 am the Department of Plastic Surgery has their Divisional Academic Conference to discuss cases of interest from the previous week. Each fellow chooses one case that is of particular interest and guides the group through all of the intricate details. It was at this conference that I was scheduled to meet my clinician, Dr. Robert Grant, along with the rest of the plastics crew. I am very grateful that Dr. Grant chose to introduce me in this manner, as I was able to meet just about the entire team all at once and immediately begin to recognize the considerations involved in a plastics case. The meeting was brief, but educational…I was truly amazed at how knowledgeable every one of these surgeons are…they were not only freely tossing around language I couldn’t follow, but were also quoting coded procedures and classifications off the top of their heads.
After the conference, I followed Dr. Grant to his satellite ambulatory clinic where he holds office hours. This was a casual environment and a nice way to start my summer immersion. We saw patients together, followed by debriefing periods in which Dr. Grant would explain his thought process involved in the diagnosis and allowed me to ask questions on just about everything.
As Dr. Grant’s research lab is currently in flux for a few weeks, the remainder of the week was predominantly spent doing rounds with the plastics team and observing lots of procedures in the OR. While both of these experiences were very exciting, rounds were also very nerve-wracking. There are so many patients to see before we hit the OR that we were essentially running from room to room.
On the other hand, the OR is surprisingly much less stressful, yet still very entertaining. I essentially have the freedom to roam around the different rooms and observe the most interesting of the plastics cases...which is very cool. Some of the more interesting ones were a bilateral mastectomy with breast and nipple reconstruction, a ventral hernia repair via surgical endoscopy (using a tubular probe with light and camera apparatus to view internal organs on a monitor) with circumferential abdominoplasty, and an abdominal wall reconstruction after excision of a sarcoma …however, I will save the details for a later post.
Tuesday, June 26, 2007
The conditions of the patients range from serious to stable. Two of the more serious patients in particular were of interest to me. Baby X (can't use the real name, or I will be fired), for example, was undergoing treatment using an experimental head cooling device called the CoolCap. It allows the baby's head temperature to be regulated by circulating cold water inside plastic tubes in contact with the head. It has been shown to prevent brain damage in newborns who have been oxygen deprived supposedly by reducing brain metabolism, although the mechanism is not totally understood. What is understood, however, is that the CoolCap is far from cool looking. I suggested putting some type of design or insignia on it. If it was my kid, I'd probably write "mofo" on it, just so the other babies would recognize.
Baby Y (again, I'll get fired) was experiencing obstruction in the bowels, though the exact cause was unknown. It was decided last week to schedule him for exploratory surgery with Dr. Spigland (Nathan's clinician) on Monday. Having visited this patient each day last week, I felt compelled to see his operation. So I went yesterday, and it was pretty messy. Dr. Spigland started by first pulling out his intestines and examining them. There were many perforations, and several parts of the bowel were necrotic (it was literally falling apart). At the end, the small intestines were separated between the duodenum and jejunum (which are close to the stomach in the intestinal tract), and a tube was inserted. He was closed up, but will need additional surgery in the future. All of that surgery gave me a hankering for some German blood sausages.
My goal while I am here is to do rounds in the pediatric and adult ICUs as well to see how patients of various age groups are treated. In addition, I am working on a project involving the modeling of infant lungs, but I will have to write about that at a later point.
Drs.: "We need to measure this from XYZ data"
Engineers: "Sure, we can do that."
Followed by literature searches and then design/implementation of some algorithm to accomplish. In general though, we as engineers are usually never concerned with the finer points of patient care (unless you work in industry and then, understandably, you are concerned with anything that can help turn a profit), just how to get Y measure from X data. On the flip side, most doctors tend to treat the output from engineer designs as blackboxes. As long as the result is correct, their happy. Its just a fundamental difference in mindset. I think it will take a special set of people (like biomedical engineers) that take a step back from the super-specialized form of education that modern society praises and back into the realm of inter-disciplinary, generic, "I know some of a lot of subjects" education, so that no matter who you're discussing a project with, you can follow along, and possibly even translate from "Doctor-ish" to "Engineer-ese" and back. At any rate, I digress.
This would be the first time though that I would get to see things from a clinical perspective. The first time I would have to be more than an engineer in a sense, and that was a bit unnerving. Luckily, since I have collaborated with my doctor in the past, a part of me gets to stay an engineer, and that's probably a good thing. So I met with my doctor and since I have a seen alot more than just the images most people think of when they hear the word 'Radiology'.
So in my time here I have been able to see a many things. Lung biopsy's that were border-line absurd in difficulty (and therefore took far longer than normal), and which made me understand why Dr. Yankelevitz is world renowned for performing them. I've seen the histology and cytology that is done as part of the biopsy (i.e. something other than the black and white images that I'm used to seeing). I've been in the reading room where dozens of ICU X-ray images are read multiple times a day at rapid speed. I definitely have been busy this past week.
I know that soon I'm going to shadowing several more groups of people before my time is out, so we'll see how that goes.
Monday, June 25, 2007
I've had the chance to observe Dr. Riina working with both technologies he uses to treat aneurysms – one involves opening up the skull, searching through the brain to find the aneurysm, and clipping the aneurysm with what looks like a simple clip structure. The other method, coil embolization, is much less invasive and involves snaking a catheter up the femoral artery to the brain and filling the aneurysm with as many as 80 (!) metal coils, in extreme cases. The decision whether to do a craniotomy or use neuroradiology depends on many factors including shape and location of the aneurysm, and health of the patient apart from the aneurysm. However, there is no strict rule, and so the decision depends many times on the individual judgements of each doctors.
Watching these surgeries from the sidelines, I have also had the opportunity to talk with anesthesiologists and medical students about the various unexpected problems that arise during surgery. In the one case I observed in which the skull was opened to clip an aneurysm, Dr. Riina found that the brain was very full (high blood pressure) upon opening the skull. The doctors attributed this to lung problems that affected the patient’s ability to get rid of CO2. However, the patient had either not revealed or not known about this when giving her medical history. The anesthesiologist had to act to administer certain drugs to try and balance decreasing blood pressure with providing enough oxygen to the patient.
I also observed Dr. Pierre Gobin, also in neurological surgery, treating retinoblastoma (eye cancer) with a method still in clinical trials. His method follows as a natural extension from angiogram techniques and involves snaking a catheter up to the artery feeding the brain, and injecting small amounts of chemotherapy drug to the eye. Apparently the decreased amount of chemotherapy drug reduces risk of other tumors developing later on in life.
My main impressions from the first week were first, hospitals are run very inefficiently. Lots of time is wasted waiting around for the doctors or patients to show up. Second, there are needs for technology to both better treat patients once the illness is known as well as improving diagnosis and the determination of treatment, so that perhaps diagnosis and treatment can become more of a science in the future.
Sunday, June 24, 2007
What do Kidneys do?
In a nutshell, a kidney is responsible for maintaining physiological homeostasis that is required for the proper functioning of the body. It involves the regulation of the body's fluid volume, mineral composition and acidity by excretion and reabsorption of water and inorganic electrolytes. Kidneys also are vital in ions regulation such as sodium, potassium, chloride, calcium, magnesium, sulfate, phosphate and hydrogen, all of which are required in certain concentrations for the normal functioning of the body. A well known kidney function is the excretion of metabolic waste such as urea and other organic osmolytes. Another important function of the kidney besides waste removal is the release of 3 vital hormones namely: erythropoietin(for red blood cell production), renin( for blood pressure regulation), and calcitriol( active form of vitamin D for calcification in bones).
Where do all these things take place?
Everyday, the kidneys filter about 800 liters of blood through its tiny units called nephrons and later reabsorbs ~ 99.9% of it leaving 2 liters of urine. There are about 1 million of these nephrons in each kidney, each of which is endowed with a glomerulus(filtration site) and reabsorption/secretion tubules. The great abundance of these nephrons is advantageous in that a person may have a large number > 50% of them dead and still maintain normal kidney function. Thats is one reason why a kidney donor can still lead a normal life with only one kidney functioning. A kidney transplant is needed when there a renal failure, where the 2 kidneys can no longer maintain the required homeostasis by removing waste products, etc.
Why do Kidneys fail?
Most kidney diseases attack the nephrons, causing them to lose their filtering capacity. The most common causes of kidney disease are diabetes and high blood pressure. Diabetes (high blood glucose) damage and obstruct the reabsoption mechanism of the nephrons leading to Diabetic nephropathy. High blood pressure also damage blood vessels in the nephrons to cause renal failure. Other causes of renal failure include: glomerular diseases, congenital kidney diseases, poison, and trauma. ohh yea, I will finally delve into the more interesting transplant section.
Transplant of Kidney...
A lucky patient who has been praying and patiently waiting for a donor finally has his/her wish answered. He/she has to face the scapel! There are over 100,oo0 people awaiting for kidney transplants in the U.S.; and the current wait time is ~ 7 years. The only requirement is that receipient's blood type matches the donor's blood, i .e., O type gets O. Due to better targeted immunosuppresion, the blood antigen do not have to match. For instance, O- blood type donor can donate to O+ receipient and vice versa. Also other previously important prerequisite are no longer necessary....Thanks to the great strides in immunology!
Once the patient has been matched and neccesary paperwork has been done, its time to face the scapel. The incision is made either on the right or left pelvic starting right above the bladder. The surgeon's intention is to graft the new kidney without tampering with the failed ones by attaching the renal artery and vein of the graft to the corresponding renal artery and vein (upstream) of the native kidneys and then suturing the ureter(graft) to the bladder. I haven't found the answer as to why the failed kidneys are left intact. So once the new kidney is sutured in place, the surgeon makes room for it around the pelvic cavity by sh0veling intestines, etc away... The patient now has 3 kidneys, 2 of which are failed.. The operation takes ~ 4 hours and the patient would typically stay for 2 days in the hospital for observation. It takes about 2 - 3 months or even sooner for complete renal function recovery.. Just this 1st week, I saw a kidney transplant from a 3 year cadaveric( non-living) donor, a kidney transplant from a 56 yr-old living twin brother donor to his HIV-positive brother.., and a kidney/pancreas transplant. It is so astounding how knowledgeable surgeons are as every case is completely different from others. Some cases require the administration of 3 combinations of immunosuppresants to avoid organ rejection, while some require minimal immunosuppresant use.
For kidneys, obtaining a kidney from a baby is much better and than a kidney from an older person whose nephrons are over 50% dead. Dr. Goldstein has performed a trasplant from a 17-month old donor. In theory he says, it can be from as young as 7-month old or younger..wow.. Apparently it grows very fast and in 3 months reaches the size of an adult kidney(fist size).
Doing Rounds...Patient Checkups..
For the 2 hospital stays, the surgeon and the medical staff(residents and med. students) would go on morning checkups to ensure that the patients are recovering well. To monitor how well the transplanted kidney is working, the amount of urine is measured..Usually it would take several hours after transplant before the kidney starts making urine.. For the most part, a kidney from a younger person regains its function faster.. Because the how hard the heart beats is intimately related to how the kidney works, the blood pressure is also monitored to ensure that the patient is normotensive. Also during this period, blood osmolytes such as albumin (responsible for oncotic blood pressure) are monitored and administered if needed. The patient is also slowly weaned off pain medication and liquid food.. If all is well in 2-3 days, the patient is released and reports for checkup in 3 months..
I have another entry on pancreas transplant but this blog is getting too long..I shall save it for a later date..
I will be spending my seven weeks with Dr. Spigland from the department of pediatric surgery as well as with two residents, Dr. Nandankumar and Dr. Afaneh, a 3rd year resident and a 1st year resident respectively. I found myself scrubbed-in the operating room on most days with rounds and consults between cases.
After obtaining a clearance badge on Monday 9am, I was greeted by a crash course in invasive surgery when my doctor told me to scrub-in during our first minute of interaction. The case involved a one month old baby boy with rare genetic disorder; his small and large intestines didn’t connect and protruded out of his abdomen. Dr. Spigland started out by using an electric scalpel to cut around the end of the large intestine freeing the intestine from the abdomen. The electric scalpel is able to minimize bleeding as it burns any contacted blood vessels. The smell of burning flesh started to make me queasy and I remember Dr. Nandankumar advising me to step back and sit down if I couldn’t handle it. Of course I had to suck it up as I know this will be the only time I’ll ever get to see this rare procedure –so I observe the doctor’s next step. Dr. Spigland then separated the small intestine from the abdomen and made a transverse cut exposing the subsurface intestine. The procedure was then to connect the large and small intestine back together and cut out any strictures (abnormal narrowing of a vessel) and abnormal intestine tissue. We found a few centimeters of dilated intestine and a few centimeters of strictures in both the small and large intestine. She proceeded to tie off the blood vessels leading to the small and large intestine using thread and staples. With blood flow eliminated, the abnormal tissue was then cut away. The intestines were then sewn together and the abdomen closed.
A few days later I was able to scrub-in with a transplant doctor who happened to be performing a kidney transplant. The patient had two failing kidneys and was in desperate need of a functional one. Luckily, she was able to obtain a kidney from her daughter. During the surgery the doctor opened the patient’s abdomen and exposed the iliac artery and vein. The kidney’s input vessels were attached to the iliac vessels by conventional thread and needle. Both the attendee and resident were painstakingly careful and precise but were able to connect the input valves in less than 40 minutes. The doctor finishes by spreading a gelatinous matrix solution with thrombin called floseal, preventing any leakage that may take place through the stitches. Blood began perfusing the kidney as the clamps were loosened, allowing the normal red color and beating of the kidney to return. The kidney’s output valve must now be attached to the bladder. Doctors have mistakenly attached the output valve to the colon as the colon and bladder are next to each other and appear similar. To prevent complications, the doctor filled the bladder intravenously, giving it a firm feel when touch. The kidney vessel is then attached to a random point on the bladder, again threaded and flosealed. The abdomen is then stitched up; the first being the fascia which directly closes the body cavity. The next layer of stitches is a mixture of loose fascia and adipose tissue, ending with the external skin.
Throughout the week, I was able to scrub into multiple other surgeries such as hernia and neuroblastoma (the most common extracranial solid cancer in infancy and childhood. It is a neuroendocrine tumor, arising from any neural crest element of the sympathetic nervous system) surgeries. All surgeries I’ve observed had no complications partly due to precise and cautious work. The doctors were very careful not to tear or break any unwanted vessels or tissue and spent most of their time painstakingly tying off vessels as failure to do so would lead to imminent excessive bleeding. These doctors are clearly good at what they do and as one resident told me they are expected to scrub in to 1000 cases before they graduate.
I have been shadowing Dr. Vouyouka in the department of vascular surgery. Vascular surgery is a general term that describes interventions on arteries and veins throughout the body excluding the heart and the brain. In general, vascular problems arise from two causes: aneurysms or occlusions of vessels. Aneurysms are localized dilations of blood vessels that may be caused by disease or a weakening of the blood vessel wall, while occlusions are blockages in vessels that may restrict blood flow. These conditions may be problematic for a patient because of the risk of rupture and/or ischemia.
For vascular problems in the lower extremities, patients may present with pain in the legs known as claudication. This pain may be mild or severe, occur during walking or while resting, and could be caused by ischemia. Untreated severe vascular problems may lead to a loss of sensation of the lower extremities and gangrene requiring amputation.
The Operating Room
The OR is not like what I expected! It’s very busy and there are a lot of personnel in the room from the surgeons and nurses to anesthesiologists. It also seems very primitive in some regards (Are staples, rubber bands, and triple knots really the state-of-the-art for wound closures?) and advanced in others (angiogram imaging technology).
One procedure I saw was an angiogram. This involves threading a catheter through the vasculature to a site of interest. Contrast dye is used in conjunction with fluoroscopy to visualize the vascular tree to looks for stenosis or occlusions. This is a really interesting procedure because the surgeons use a two-dimensional image as a roadmap for a three-dimensional procedure. They told me that “You get the hang of it; it’s like learning any other procedure”, but I’m still skeptical!
I also saw a balloon angioplasty of a leg vessel. This procedure also uses a catheter placed at a site of stenosis. A balloon is inflated at the site to help open the vessel to improve blood flow. These procedures are often now done by vascular surgeons, but were traditionally aspects of the job of interventional radiologists. In any case, the technology available to the surgeon is pretty amazing.
I also saw patients at the clinics in Weill Medical and at Lincoln hospital in the Bronx. This was really interesting because each person presents with their symptoms and it was up to the surgeon to try to figure out what was wrong. Often the patients had pain in their legs, and the surgeon can get a pretty good idea of where the problem areas in the vasculature are based on where it hurts. The vasculature system is a lot like plumbing—a blockage will cause problems downstream. Treatments might first be having a duplex, or an ultrasound of a suspected problem area. The next step might be an angiogram to better visualize the circulation. Surgery might be needed if there are extensive occlusions or an aneurysm present. I really like the clinic because each person had something different going on and you get a good sense of the “human” side of patient care.