The Lower Extremity Blocks

In contrast to the upper extremity, the nerves going down the lower extremity are not so neatly packaged. For the arm, we can usually anesthetize the brachial plexus with one injection. There are some blocks that miss a specific nerve (like the musculocutaneous or intercostobrachial), but for the most part, hand, wrist, and forearm surgeries can be handled quite easily. In contrast, the nerves innervating the lower extremity don't run together. To achieve surgical anesthesia, we often have to target two nerves in different compartments of the leg. A combined popliteal-saphenous block is sufficient for foot or ankle procedures. Both a femoral and sciatic block are necessary to get all aspects of the knee (though we usually only do the femoral so we don't delay physical therapy). For patients with trauma, positioning for the blocks can be tough because we need to get to different aspects of the leg; sometimes, we have to be creative and sacrifice ergonomics to block the patient who is in too much pain to move.

The truth is, lower extremity blocks do not have to be in the armamentarium of every anesthesiologist. A single shot spinal or epidural catheter can achieve many of the anesthetic or analgesic requirements, though it has other undesired consequences like affecting the nonoperative leg. I've come to respect lower extremity blocks, though, because a lot of leg, ankle, and foot surgeries happen in patients with many medical comorbidities. Patients requiring a knee replacement are often older and obese. Diabetics get foot and ankle complications that require amputation. Not all these patients are the lowest risk for a general anesthetic, and knowing how to do a good leg block can be the optimal anesthetic plan.

Image shown under Creative Commons Attribution Share-Alike License, from Wikipedia.

The Upper Extremity Blocks

Understanding how to block the arm and hand for surgery is a crucial skill for an anesthesiologist. It can allow the avoidance of general anesthesia and its attendant risks, which can be critical for the extremely ill patient and be helpful to improve the perioperative experience of the healthy patient. Whereas a lower extremity surgery can be replaced by a spinal or epidural technique, there is no equivalent for the shoulder, arm, or hand.

Each upper extremity block has its challenges. For example, blocking the nerve roots between the interscalene muscles has steep learning curve because the ultrasound tends to slide down the neck due to gravity. When I first started this block, I always lost my ultrasound image as I concentrated on my needle. I would then attempt to fix the ultrasound in place and develop hand cramping from bad ergonomics. Placing a catheter next to the nerves in the neck also fails commonly because the targets are so shallow; movement of a centimeter can result in a failed block. Understanding this block is important as well; it often misses the ulnar or pinky side of the hand so it's not appropriate for those surgeries. Patients can develop hoarseness, a droopy eyelid, or changes in breathing from a successful block. Much of the rotation was understanding these types of details about each nerve block. By the end of the month, I became very comfortable with the suprascapular block, which is a standard one for lower arm or hand surgery as well as the infraclavicular block, a more challenging block for the hand, but better for catheter placement. With ultrasound, the risks with these procedures are minimized, so I did fewer old-school pre-ultrasound blocks like the axillary approach to the brachial plexus.

1900

Hooray! This is the 1900th post for this blog. I've had a blast writing, and it's really been a privilege and an opportunity. This blog has put me in touch with readers who were curious about medical school, and I've helped a few take that plunge and get in. I've met students whose interest in anesthesia led them to this blog. I've heard from patients who've reached out after reading some of my thoughts. I've expanded my writing and gotten involved in The American Resident Project. Thank you to all who read this and all who send me an email or leave a comment. It's been such an eye-opening, fun, and satisfying part of my life. But it's a time-consuming one as well, and I'm going to take a break for a week after this blog. I'll see you next Monday.

This blog was never meant to be a public education tool. But occasionally, I want to get up on a soapbox and share an idea. If I were to write to a reader about something I've learned from residency, I would write about what an anesthesiologist does. Few people understand anesthesiology. It seems like such a simple thing, to have someone "go to sleep," and there are perceptions that anesthesiologists simply do crosswords and update their investments in the operating room. Pharmacological and technological improvements have made anesthesiology safer, but this has given anesthesia the reputation of being easy, simple, unimportant. I argue that this is a major misunderstanding.

In the operating room, I take a patient and render him in a state suitable for surgery. I make him appropriate for a surgeon to take a scalpel and cut into him, to laser a vocal cord polyp or remove a vascular cancer or to graft a vein onto a heart or to replace a joint. I have to understand the surgery and its needs and balance it with the patient's other medical problems to come up with the appropriate pre-operative testing, drugs, monitors, and post-operative disposition. At an advanced level, I think about the system's resources, the patient's recovery, and the cost of care. I bridge the medical side with the surgical. I not only have to understand the management of congestive heart failure, adrenal insufficiency, and rheumatoid arthritis, but I also have to understand the anatomy where the surgeon is working, how a neurosurgeon monitors nerves he's working near, and where a cardiac surgeon places his bypass cannula.

But I also want to get across that anesthesiology is more than just medical knowledge and experience. In providing general anesthesia, we take full responsibility and control over someone's body and shield it from what the surgeon must do. When I push my propofol, I commit to breathing for the patient. When I roll a patient back to have his aortic aneurysm repaired, I take responsibility for the massive blood loss that will ensue. When I allow a neurosurgeon to open up the skull, I must do everything I can to preserve brain function. This weighs heavily on anesthesiologists. It's an emotional burden we take day after day. It's easy to imagine the courage a surgeon must have to cut someone's skin, but it's easy to forget the courage an anesthesiologist has to allow him to do so.

We are always in the background, never in the spotlight. Nearly all that we do happens when the patient is asleep. Surgeons struggle with this too; their patients only see the scar and sutures, not that 3-hour anastamosis or challenging laparoscopy that was saved from becoming open. Most patients can imagine what a surgeon does. This blog is written to help patients get a little insight into what an anesthesiologist does. We don't need fanfare, but we do appreciate recognition that what we do is more than pushing propfol and putting our feet up.

Outpatient Surgery Center

We spend half of our regional anesthesia time at an outpatient surgery center. All of the procedures done at the OSC are small; it's a freestanding facility without the ability to admit patients overnight, transfuse blood, or even send labs. For anesthesiologists, this is a big deal. We plan for the worst case scenarios and have to ask ourselves what we would do if an emergency happens. As a result, all the cases done at the outpatient surgery center are small cases on relatively healthy patients.

As residents, we only go to the outpatient surgery center for our nerve block rotation. Many of the cases performed are orthopedic; we do knee arthroscopies, ACL repairs, shoulder arthroscopies, wrist and hand surgeries. Many of these procedures can be done entirely under nerve block. For a patient undergoing finger surgery, all the patient received for the entire procedure was mepivicaine for the nerve block and perioperative antibiotics. To me, this is pretty impressive; I'm used to cases that require a handful of medications to complete. To have a patient numb and wide awake for a surgery is an accomplishment, and it's ideal because the patient can go home pretty much after surgery since he got no systemic sedation.

Since outpatient surgeries are quick, we get a lot of nerve blocks. We can do up to fifteen blocks a day in rapid sequence, and it's both satisfying and educational. For surgeries where we don't expect much pain, we design the block to wear off quickly so the patient won't have a numb arm or leg all day. For surgeries with moderate pain, we try to tide the patient over the night be using a long-acting local anesthetic. And for surgeries with severe pain, we can leave in a catheter which the patient goes home with that can infuse local anesthetic for several days. The decision making process is also an important aspect of learning regional anesthesia.

Ultrasound

The ultrasound machine is part of every anesthesiologist's armamentarium. We most commonly use it for putting in central venous access, scanning the internal jugular or femoral veins. But ultrasound can also be a tool for placing difficult IVs or arterial lines, evaluating the heart (both transthoracic and transesophageal), and placing nerve blocks. Thus, my month on regional anesthesia taught me a lot about ultrasound.

Most physicians can get away with a rudimentary understanding of the physics, machine, and computing algorithms. However, to successfully do nerve blocks, anesthesiologists need more than a superficial understanding of ultrasound. Our targets are millimeters wide but can be several centimeters deep. They are surrounded by critical structures and can be tricky to visualize. The goal is to see the needle tip at every moment as it reaches the target. This seems easy, but getting the needle, ultrasound beam, and target aligned in one view is an incredibly challenging technical skill to learn.

Ultrasound taught my hand fine, miniscule movements. When I first started, I thought I made small adjustments, but I was moving the probe millimeters at a time - a reasonable action if I were placing a central line into a jugular vein, but ineffective in locating a bundle of peripheral nerves. But over the four weeks, I developed better judgment in directing my needle at the right angle and trajectory and better muscle memory in adjusting the ultrasound beam to catch the needle and target at once.

Furthermore, I gained a deeper understanding of ultrasound physics and mechanics. Though it sounds dry, it helped me understand how to select the correct probe and orientation for each block. The more challenging aspect was learning how to adjust the machine's algorithms in displaying the data. Sometimes when visualization is poor, changing how the ultrasound waves are interpreted can make a needle or target more apparent. As a medical student, I was intimidated by how many knobs and dials the ultrasound machine had; now I have a reasonable understanding of what they do and how to use them.

Anatomy

For most medical students, the brachial plexus is a nightmare. The nerves from the cervical and upper thoracic spine that give sensation to the arm seem to have no rhyme or reason. They branch, connect, intertwine, and split off seemingly randomly, and for most of us, it is an exercise in memorization and then prompt amnesia.

I had thought myself free of the brachial plexus. But unfortunately, understanding the sensory innervation of the arm is essential to the regional anesthesiologist. The anesthetic plan differs whether the surgeon is working on the index finger versus the pinky, the wrist versus the elbow versus the shoulder. Performing a successful nerve block requires an understanding of which nerves need to be anesthetized and how to get to those nerves. Sometimes we have to block the roots as they come out, sometimes we block the divisions. We also have to understand the nearby anatomic structures to avoid crucial vessels and guide our needle. Which muscle layers overlie the nerves? How is each division situated in relation to the artery?

We don't learn most of this in our general anesthesia rotations. Although we study it for our tests, our month on regional anesthesia is the opportunity to apply this theoretical knowledge of anatomy into practice. Over the month, I saw different anatomic variants of the normal. I recognized how other factors - trauma, obesity, swelling, positioning affect the difficulty of the block. This month has helped me place anatomy into a clinical context. Of course, relearning brachial plexus anatomy was just the beginning; I had to pull out my notes on innervation of the leg, the lumbar plexus, the abdominal nerves, and other factoids from the first year of medical school.

Image shown under Creative Commons Attribution Share-Alike License, from Wikipedia.

Regional Anesthesia

I spent the last month on my regional anesthesia rotation, our immersion into nerve blocks. I'm one of the last residents in my year to do regional anesthesia. Although I got the usual pre-rotation jitters starting something completely new, I quickly got the hang of it and had a great month. Nerve blocks are primarily used for orthopedic surgeries, though we do them for a wide variety of procedures, from nephrectomies to mastectomies to open hysterectomies. Some are done specifically for post-operative pain, like a femoral nerve block for knee replacements. Others are intended to be the primary anesthetic, such as numbing an entire arm for wrist surgery. Although much of the focus of the rotation was becoming proficient in the procedures, regional anesthesia has many other facets that encompass systems based practice, operating room efficiency, understanding surgical requirements, and managing patient follow-up.

The concept of regional anesthesia is simple. If the surgery is localized to a specific area innervated by specific nerves, then blocking those nerves with local anesthesia will be sufficient for the surgery (or for post-operative pain management). It requires much less amount of medicine than the surgeon infiltrating local anesthesia indiscriminately. And it may make general anesthesia unnecessary. Thus, a good sense of anatomy and peripheral nerves is all a regional anesthesiologist needs to devise a plan of action.

Pre-op Clinic

Pre-op clinic, a requirement for all anesthesiology residents, is a strange and fascinating creature. We don't particularly like it, since most of us went into anesthesia to avoid clinic. And at first, it seems exceedingly easy. The vast majority of patients, having gone through the surgeon's office, are appropriate candidates for getting anesthesia and surgery. The pre-op visit assures that nothing is missed, that the patient receives all their instructions and education, and that labs and studies are reviewed. Practically, it means that 90% of the visits are very routine, and for anesthesiology residents, it can be a little tedious.

However, having done it every year of my residency, I've noticed that it's changed over time. As an intern, I was quite apprehensive about everything; I ran all my patients in detail by my attending, and I learned a lot. Gradually, I've done a week or two of pre-op clinic each year, and now at the end of residency, I feel quite independent. Perhaps I'll give my attending a one-liner for complex patients, but for the most part, I operate autonomously. Having done anesthesia for pretty much every surgery, I can tell a patient exactly what to expect; some need epidurals, double lumen tubes, arterial lines, blood transfusions, or avoidance of general anesthesia.

I also appreciate the nuances much more now. What happens when a patient has severe multiple sclerosis? Myasthenia gravis? End stage COPD? Fresh cardiac stents? Instead of defaulting on my attending's judgment, I now have a good sense of what I'd do as the anesthesiologist and can formulate a reasonable plan. Although clinic is not my favorite activity, at least I have a better grasp of its finer points.

Sorry for the Gap in Blogs!

Like anything, residency comes in ebbs and flows. Some months, especially for new rotations, are busier and more exhausting. Even if I don't spend that much time in the hospital, new rotations can be mentally and emotionally exhausting. It's strange because I don't work as long hours or as many days as I did in internship, I feel like I have more things competing for my time. Perhaps it is this strange phenomenon where getting a little free time paradoxically makes me more busy than if I had no free time at all. This is true talking to older attendings who, during their residencies, gave up all hope of a life outside the hospital. By setting such expectations, all their hours were focused on medicine, but this was considered a necessary sacrifice. Now, I have an inkling of freedom, and I want to cultivate all these extracurricular interests. I dabble in a few, and suddenly, I have grossly overestimated what I can do, and I'm frantically scrabbling to prioritize, salvage, do, play, and sleep. In any case, I know that my life is much easier than it was in internship, but I'm finding it tougher to blog consistently. This next month won't be any better as I'm starting in the cardiovascular ICU, a notoriously busy month. I'll still be blogging about last months activities, though, on my regional anesthesia rotation.

Electroconvulsive Therapy

If you look back far enough in this blog, you'll find older posts on electroconvulsive therapy. I was recently assigned to provide anesthesia for ECT treatments. We provide a short several-minute anesthetic while a psychiatrist induces a seizure in a patient with severe refractory depression. When I first did ECT anesthetics, I followed the recipe without a good sense of all the steps. I was overwhelmed with such a brief yet involved anesthetic and depended quite a bit on my attending. This time around, at the end of my residency, it was a completely different feel. I felt completely independent and relaxed. I not only understood all the components of the anesthetic recipe - ondansetron, ketorolac, remifentanil, etomidate, hyperventilation - but I knew why they were chosen and what alternatives I had. I knew the crazy physiologic derangements that come with electroconvulsive therapy and how to treat the bradycardia, tachycardia, hypertension, inadequate seizure, and status epilepticus that could happen. To me, this was an epiphany to show me how much I've learned in the last few years of residency.

OR Management

I have to say, after two weeks trying to run the board and learning about principles of surgery center management, I don't find it as fun as direct patient care. Management is a frustrating business. I'm constantly trying to negotiate with surgeons and nurses about optimizing the flow of the surgeries. Changes which should be easy take much longer to happen. Implementing a new policy involves so much red tape. I move mountains to make things happen, and at the end of the day, it saves half an hour. When something goes wrong, the buck stops with me, and I have to fix it, whether it is an emergency or an inconvenience. I went into medicine to take care of patients, not systems.

Nevertheless, it was a really enlightening and educational experience. It taught me to be aware of the surgery center as a whole. By the end of the rotation, I knew what was going on in each room; I knew which surgeons and anesthesiologists were where, which rooms had delays, which rooms were moving fast. I knew where my resources were if something went wrong. I had a good grasp of how to make things happen. I became a better leader. I learned about my management and communication skills. And I got a keen awareness of the things that matter in our medical system to administrators. I learned where our inefficiencies lie, where we can make improvements. I have a little better sense of why the American health care system is so broken. I know how gargantuan a task it is to fix it.