Charlotte ter Haar

University of Illinois at Chicago
Bioengineering


Week 6, Part 2: Taking an active role

While I understand the value in observing in the clinic, it has been fun to interact with the technology when we are given the chance. Earlier in our rotation, a rep from AngioDynamics was in the IR suite to demonstrate the VenaCure laser ablation system for varicose veins. We also go to talk to her about the AngioVac device. Earlier this week, we spoke with a rep from Gore, who showed us several stents that Gore produces. I got to deploy one (not in a patient, obviously), which was pretty cool. We have also had the opportunity to handle two different biopsy devices, and to practice using the ultrasound. Actually interacting with the technology always given me a better understanding of the learning curve required to use any new technology. For example, I did not find either of the biopsy devices to be intuitive, and had to go through several trials until I understood which buttons/levers to push and when.

 

Overall, I am very thankful for the opportunity to shadow in IR and for the wonderful mentorship I received in this program!

Image: Dr. Bui demonstrating the ultrasound on Emil.

Week 6, Part 1: Representation

I’ve been struck by the lack of females in Interventional Radiology. I haven’t met any female attendings in IR at UIC and neither of the fellows are female either. Since I’ve only spent time in the IR department at UIC and having a sample size of n=1 is typically never a good idea, I took my questions to the internet to see if I could find some more robust numbers. A physician and a certified medical laser safety officer (CMLSO) published an article in December 2013 in the Seminars in Interventional Radiology, titled “Pregnancy and the Working Interventional Radiologist.” The article cites that 2% of all interventional radiologists are women. While that statistic is disheartening, the conclusion of the article declares that a practicing interventional radiologist can stay productive throughout her pregnancy, providing that a few additional measures are taken to reduce injuries “related to the anatomic and physiology changes of pregnancy.” This conclusion is uplifting – I suspect that some women are wary of the radiation exposure in such a career. (Side note – interventional cardiology, which has a similar length-training, also requires a fellowship following residency, and also has significant radiation exposure, has females represented at approximately 4%, not a much better showing than IR).

Note: The image is of Dr. Spencer from Riaendovascular, because I think it’s important to see women in roles in which they are not often found.

Week 5, Part 2: Repeating procedures

We have seen several dialysis patients in IR, which was a surprise to me at first. Patients who receive hemodialysis often have a connection made between their artery and vein – called an AV (arteriovenous) graft or fistula. An AV fistula is the direct connection of a patients’ artery and vein, and an AV graft is a connection made with plastic tubing. A patient’s native veins cannot handle the blood flow from hemodialysis long-term, so AV grafts and fistulas allow for increased blood flow and better hemodialysis results. Many patients develop blood clots within AV grafts and fistulas, which can significantly impede blood flow during hemodialysis. As such, IR often sees these patients in order to declot their AV graft or fistula. Dr. Bui told us that the 3 month patency rate following declotting is 40%. That is shockingly low – 60% of patients who require a declot must return in less than three months for a repeat procedure! I am curious if there is a way to improve the long-term patency of these AV grafts and fistulas – or even better, a way to avoid hemodialysis in the first place.

Image: Shows an AV graft, from Wikipedia page on Hemodialysis

Week 5, Part 1: In the vein of IR

We had the opportunity to hear from a company rep for Angiodynamics about their “VenaCure” laser for ablating superficial varicose veins. Essentially, a laser is inserted into the vein & then turned on while slowly pulled out of the vein, and the vein becomes destroyed. The blood that was drained from this region will find a new way back to the heart through deeper veins. Varicose veins are the result of venous valve insufficiency, which causes blood to pool in the veins near the feet, and builds up pressure on the walls of these insufficient veins. While the laser treatment is interesting, it got me thinking about deep vein valve insufficiency. You cannot ablate a deep vein with valve insufficiency, so there are currently not many options, other than monitoring and attempting to ameliorate symptoms & prevent the formation of ulcers. The technology for artificial heart valves is tremendous and widely explored – while an insufficient heart valve may be more life-threatening than insufficient venous valves in the legs, I am interested by what I perceive to be a relatively unexplored space for treatment options.

 

Image: From Diagnostic Imaging Services, showing the before and after of superficial varicose vein treatment using the VenaCure EVLT.    

Week 4, Part 2: Navigating 3D space with 2D imaging

Lately, I’ve had Pokemon Go on the mind. I am fascinated by the implementation of augmented reality and what it could mean for imaging in medicine, especially in Interventional Radiology. I have been struck by the lack of dimensionality in the imaging techniques used in IR. That is to say, in any given image, an entire dimension is lacking – the images have no depth. To me, this seems like a limitation, as our anatomy is unquestionably three-dimensional. For example, in a transarterial chemoembolization (TACE) procedure, the Interventional Radiologist must find the arterial feeder to the tumor, but with the two-dimensional imaging, it can be difficult to discern which exact artery is actually going to the tumor. If the imaging of the arteries also had depth, this would be far easier. While we saw a cone-beam CT used once; however this was the exception, not the norm. The cone-beam CT gave more of a three-dimensional view of the liver (in that case), but the software took a very long time to process the images and generate the “3D xray.” Another example where 3D imaging would be an asset is the transjugular intrahepatic portosystemic shunt (TIPS) procedure. In this procedure, a shunt is created between the hepatic and portal veins, the bypass the liver. While the interventional radiologists can see a 2D relationship between the hepatic and portal veins, they cannot see depth, so creating the access point between the two veins can be very challenging.

 

Being able to read images and perform the procedures that I have discussed in this post are two components of the “skills set” of an Interventional Radiologist. They require training, practice, and finesse. Sometimes I wonder whether physicians (or any skilled worker, for that matter) feels a conflict between the development of a new technology that advances their field, but may make some of their current skills less relevant.

Image: From VIRChicago, showing the placement of the stent in a TIPS procedure, between the hepatic and portal veins.

Week 4, Part 1: The Elegance of Interventional Radiology

 

I have started my second rotation in Interventional Radiology (IR), and I am already impressed by this specialty. Once again, I can tell that I got lucky with a fabulous mentor – Dr. Bui has been great at getting us acclimated to the department & understanding the basics of his specialty. In addition, everyone that we have interacted with has been incredibly helpful and happy to explain the procedures to us. On our first day, Dr. Bui was talking about the development of interventional radiology as a field and why he likes it, and he said something quite striking – “If you see a procedure that is not elegant, there is a better way to do it.” His words have stuck with me this week, and give a perfect illustration of my impressions of IR – the procedures all seem quite elegant. It is fascinating how much they can help a patient with such minimally invasive procedures. The one challenge that seems to come up in procedures is the navigation of the catheters and wires through the vasculature. Sometimes the physicians have to take a few passes to get into the right vessel, and certain procedures offer additional challenges. For example, in a case with portal hypertension, the interventional radiologist may want to insert a balloon catheter into a shunt vessel – a vessel that is normally not there, but has opened up to allow the backed-up venous blood from the portal system to return directly to the heart without passing through the liver. These vessels sometimes have 90 degree turns, and the balloon catheters are quite stiff, making it difficult to navigate that turn. Moreover, these shunt vessels are not typical vessels, so they are often more delicate. Note: the image above, from Boston Scientific, shows a wire coil being inserted into a vessel through a micro-catheter, a procedure we saw performed to occlude shunted vessels.

Week 3, Part 2: Pain Clinic & Patient Communication

We spent one day in the pain clinic, which deals more with patients with chronic pain, rather than the acute pain involved with surgery. The pace was very different in pain clinic – it was the most patient interaction we had on the whole rotation, as it was an outpatient clinical setting rather than the operating room. One thing that I found frustrating was the lack of patient education and communication. For example, there were two procedures cancelled because the patient had only stopped taking their blood thinners the day before they came into clinic. The attending that day prefers that the patients are off their blood thinners for three days before the procedure, as there is risk of bleeding into the thecal space. However, this is not a set requirement for this procedure – the fellow in the pain clinic told us that the society for regional anesthesia sets guidelines every couple years, but that the guidelines are not necessarily evidence/research-based. Therefore, what happens is largely provider/attending-based – that is, if a different attending had been there that day, maybe those two procedures would not have been cancelled. A few thoughts on this:

1.     It is very reasonable for a provider to only do a procedure on a patient that they feel is a comfortable and safe procedure.

2.     Why are the guidelines not evidence-based?

3.     Why is there no standard of practice within a given pain clinic for how long patients must be off their blood thinners prior to these procedures?

4.     Why are patients not told to stop taking their medications three days ahead of time, if that is what the provider is expecting?

It was especially frustrating to see this, as one of the patients was an inmate who had two guards escorting him. That wasted time for all three of them, not to mention to providers that saw him that day. I also imagine that rescheduling that appointment is even harder as an inmate.

 

Photo: I forgot to take any photos of myself in pain clinic, but here is one of Emil with a partial skeleton.    

Week 3, Part 1: Simulation and MRIs

We had the opportunity to see the anesthesia residents in the simulation lab last week, and I am still struck by how advanced and yet insufficient these simulators are. They can cough and blink, they have heart, lung, and bowel sounds, and you can put IV fluids in them, and yet I still don’t think they are adequate for training students. While I think there is huge value in using simulation equipment, the faculty at UIC seems to unanimously accept that the simulators are not realistic for practicing intubation. As a disclaimer – I may be biased, as I worked on a simulation project for teaching intubation in my undergraduate curriculum – but I find it so interesting that students are asked to learn skills on manikins that do not mimic the experience on a real human patient. If anything, I fear that students will learn to use too much for a given procedure, since the mouths are difficult to open and the skin is hard plastic. I think the idea behind simulation equipment is genius, and I am curious about the role that virtual reality will play in medical education & medical simulation. I predict that the field of medical simulation will look very different in 15 years!

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Our team also went to MRI for a half day to observe the role of anesthesia for MRI procedures. Most young children who need an MRI will get anesthetized – it can be quite scary and overwhelming to be in that machine for 45+ minutes, and the MRIs can be useless if the patient moves too frequently, which can also be a challenge for pediatric patients. As such, the department now schedules all pediatric MRIs for the same day, so they know that they will have a pediatric anesthesia team at the ready. This significantly speeds up the entire process! It’s always satisfying to see schedules worked out like this in the hospital, ones that truly improve efficiency. Adults who know that they are claustrophobic are also often scheduled on the same day and may be anesthetized. It was really cool to see how many non-ferrous devices and equipment have been specifically designed for the MRI rooms. In our discussion with the MRI technician, we found out that one technology that is still lacking is an MRI-safe pacemaker. There are certain pacemakers that are “MRI-compatible” or “MR – conditional” and allow patients to get MRIs under very specific conditions (according to the MRI tech, patients with these pacemakers can typically get MRI scans of their brain but not much else), but if a patient does not happen to have one of those MR-conditional pacemakers, they cannot get an MRI. 

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Week 2, Part 2: There are 100 ways to skin a cat

Today’s blog post will focus on two quotes that I wrote down while observing the anesthesiology team this week.

Just as there are 100 ways to skin a cat, there are 100 ways to manage a patient well under anesthesia. While a lot of the anatomy and pharmacology can be considered cold, hard science, how to actually manage your patients is where the art of anesthesiology comes in.” – 4th year resident at UIC.

I felt like this conversation really brought new insights about my observations over the past two weeks. Often I have wondered why an anesthesiologist is making a certain decision – how do they decide at what oxygen level they will ventilate the patient? Is it better to try and push the oxygenation level closer to room air, or are there no problems with keeping it at 50%?  Why do they choose one muscle relaxant over another? If you can adjust either the respiratory rate or the positive-end-expiratory-pressure and get similar results, why do you pick one over the other? I have found that the anesthesiologists we have been observing care greatly about their patients, and understand all of the measures that they are taking to provide quality care, and yet, are not always able to say why they choose one path over another. Maybe it would be possible to do more research on which methods are “better” in certain situations, but at the same time, I do see how many different variables they are attempting to control at once, and I wonder how effective such a study would be in truly ascertaining variable patient outcomes.

The second quote that really stuck with me this week was from a conversation with Dr. Feld, an attending in anesthesiology. While discussing innovation with him, he said:

If you want to get to the real root of the problem, come up with solutions to avoid surgeries.” – Dr. Feld, UIC Attending in Anesthesiology

Talk about problem-based thinking! I love this quote because he is thinking about the big picture, he is not limiting himself to an idea that surgeries will always be a necessity in medicine, and he is truly thinking about a world that would be most ideal for patients. I also love that it is problem-focused. I have spoken to several residents and physicians who suggest devices that they would like to have, that they perceive would improve their delivery of care – whether through more accurate peripheral nerve blocks, by improving efficiency, etc.  I find that it is a constant struggle for me, as someone is describing a device they want designed, to try and delve deeper and to understand the root of the problem. Why do they want this designed? What is the problem they are trying to solve? How would this change the delivery of healthcare for the patient? For the residents? For the physician?

That’s all for this week! I am looking forward to one more week with Anesthesiology.

The image:  We saw a scoliosis surgery today, where the patient must be in prone position to allow the surgeons access to the spine. I was interested in the piece of foam that the patient’s head rests upon – it as a cutout for the face, to prevent ocular injury from pressure on the eyes during a long surgery. It also has a cutout in the side of the foam (not viewable in image above) that allows the breathing tube to pass through the foam.

Week 2, Part 1: Where does the Anesthesiologist Belong?

 

In the standard operating rooms, the surgeon and anesthesiologist typically work out a place for the anesthesiologist to “set up” that will work for both parties. Typically, this is behind the patient’s head, but adjustments are made if the surgeon is operating on or near the head. I have been surprised by the two experiences I’ve had outside the standard ORs: in the “embo” lab and in the “cath” lab. In both of these rooms, there is still a designated space for the anesthesiologist, but it seemed to be far from optimized. In the embo lab, the location of the anesthesiologists meant that tubes and cords were stretched across the room (see image above). In the cath lab, the anesthesiologists could not see the screens that the interventional cardiologists see, meaning that they did not always know what was going on in the procedure. In addition, the anesthesiologists’ arterial line was removed in order for the interventional cardiologist to gain access to the arterial system, which meant that the anesthesiologists lost their blood pressure readings on the monitor, as well as the “cardiac index” reading. Both of these measurements are important for patient monitoring. I find it surprising that in these operating rooms, where patients are often in critical condition, the anesthesiologists often seemed to have to carve out a niche for themselves within the room. After all, the anesthesiologist is an essential member of the patient’s care team!    

Week 1, Part 2: Da Vinci on the Mind

“There are three classes of people: those who see. Those who see when they are shown. Those who do not see.” – Leonardo da Vinci

After my first experience watching the Da Vinci robot in action, I find myself reflecting on the famous artist/innovator/intellect’s insightful words on observations. I strive, both in this program and throughout my career, to fall into the first class that he mentions. Now, on to my observations…

On Thursday we sat in on the resident’s conference about inhaled anesthetics. Following, conference, I watched a kidney transplant surgery, which took about six hours. The surgery was laparoscopic (minimally invasive), using the Da Vinci robot. The surgery itself was really interesting to watch, but it was also interesting to see how different circumstances in a surgery can change the job for the anesthesiologist. For example, in laparoscopic surgeries, the patient’s abdomen (in this case) is insufflated with carbon dioxide gas. This allows the surgeon a space within the body to navigate the instruments for the surgery. Some of the CO2 from the abdomen can be absorbed into the tissue and removed by the respiratory system, but this can drive up to CO2 readings on the anesthetic monitoring. Knowing this, an anesthesiologist is more comfortable seeing slightly elevated CO2 readings during laparoscopic surgeries.

During the kidney transplant, the patient was in the Trendelenburg position (see image below, from Wikipedia), which allowed the surgeon the best access to the surgery site.

Trendelenburg_position

In this position, the weight of the abdominal organs slides up to rest on the diaphragm. Since a patient is not breathing on their own when they are anesthetized, the anesthesiologist ventilates them using positive pressure breathing. Note – our normal breathing is negative-pressure breathing – we create a negative pressure in our lungs that drives new air in. When the patient was in Trendelenburg position, it was even more difficult to positive pressure ventilate, since you have to push the diaphragm against more weight. Placing the patient in this position is best for the surgery, but it introduces an additional challenge for the anesthesiologist.

From a medical standpoint, I thought it was very interesting that neither of the patient’s existing kidneys were removed. Prior to seeing the surgery, I assumed that one kidney would be removed so the transplanted could could replace it. Rather, the vessels of the transplanted kidney were sewn onto the external iliac artery and vein (see image, from Mayo Clinic website).

mcdc7_kidney_transplant-8col

This is logical; it would take longer to remove an existing kidney and shorter surgeries typically mean better patient outcomes. In addition, if the patient has any remaining kidney function, it does not make sense to remove their original kidneys. 

At the end of day on Thursday, Dr. Edelman gave us an overview of the stages of anesthesiology and situations in which different levels of anesthesiology are indicated. The four basic levels are:

I.               Anxiolysis

II.              Monitored Anesthesia Care (MAC)

III.            Deep Sedation

IV.            General Anesthesia

At different levels of anesthesia, patients have varying abilities to maintain their own airways, feel pain, and respond to stimuli. It was helpful to get an overview of these stages to better understand what we are seeing in the OR.

 

Week 1, Part 1: An Introduction to Anesthesiology

Thanks to the long weekend celebrating America’s Independence, we started the Clinical Immersion Program on Tuesday. All program participants (Innovation in Medicine/IMED students and Bioengineering students) met at UIC’s Innovation Center for an orientation to the Clinical Immersion Program. We discussed teamwork, expectations, hopes, fears, logistics, and did a little improv, which is always fun. Tuesday afternoon, I started in the Anesthesiology clinic. The Anesthesiology & Surgery departments took advantage of the long weekend, and the operating rooms were closed on Tuesday for cleaning/organization. Therefore, on Tuesday afternoon, Dr. Edelman showed us around the department. He took us to the Surgicenter, which is where patients are prepped for surgery, a small procedural room (not a full-on operating room), and the recovery room. Since the operating rooms had been closed, the Surgicenter and recovery room were also both empty.

SurgicenterAnesthesia cart

Above shows the surgicenter, where patients are prepped for surgery, and an Anesthesiology cart in a small procedure room.

Wednesday morning was when the real fun began. We started off the day in the conference for residents, which gave an overview on Airway Management. Dr. Banchs discussed several factors pertaining to airway management, including the anatomy and innervation of the airway, differences between adult and pediatric airways, predicting whether it will be difficult to mask ventilate or perform a direct laryngoscopy, and a comparison of different blades used for intubation. Since managing the airway is such a key component of the specialty, it was a great lecture to kick off this rotation.

Following the lecture, we split up to pair one IMED/medical student with one bioengineering student, so we wouldn’t be adding four people to any one operating room. Tooba and I saw three neurosurgical procedures. A fourth-year anesthesiology resident and a fourth-year medical student on his anesthesiology rotation were also both in the operating room for all three procedures, and they were really helpful in explaining all the various parameters that the anesthesiologists track on their monitors, as well as some of the physiology, physics, and pharmacology behind those parameters.

The first procedure, we saw a patient who had a morphine pump that delivers morphine to her spinal cord for pain management. The battery dies after 6-7 years, so it was time for her to receive a new pump. The resident knew that previous anesthesiologists had difficulties intubating her, so he used the GlideScope from the beginning of the procedure, which is a video laryngoscope that allows for real-time video feedback. It was interesting to see the intubation from the GlideScope screen, and with this device, the resident intubated the patient without difficulty. There was a tech advisor from the biotech company that produces the pump – I didn’t catch who – but she was having trouble activating the pump prior to having the surgeons place it in the patient. Eventually, she asked for the LED lights to be turned off because she was concerned that they were interfering with her procedure.

One really neat feature of the anesthesia monitors is that there is a beeping that corresponds to the pulse oximetry, but the beeping changes pitch based on the saturation. With so many numbers to watch, I thought it was cool that there was also some audio feedback.

There is a device called the Bair Hugger that is used to keep patients warm during surgery – operating rooms are often quite cold, which is nice for the surgeons who are working hard, but it is important to keep the patient warm. The resident mentioned that it takes an hour for the Bair Hugger to work, so it was not used in any of the procedures that were expected to take less than 60 minutes. However, an attending came in to one of the later surgeries that was supposed to take 45 minutes and put it on the patient just before the surgery started. It is interesting to see these variations in practices, and it makes me wonder which choices are evidence-based and which are based on what a physician is used to doing.

 

This rotation is off to a great start, and I am looking forward to seeing other facets of this specialty. I hope this post didn’t put you to sleep!


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