Circulatory Arrest

There's a morbid saying in medicine: no one's dead until they're warm and dead. That is, a hypothermic person may have none of the usual signs we associate with life - they may be pulseless, not breathing, unresponsive, with no blood pressure - and yet, if warmed up, they may reawaken. We know this from stories of children who have fallen into icy ponds, rescued an hour later, yet who sustain little or no long-term injury.

We take advantage of this in some cardiac and neurologic surgeries, and the most extreme example is circulatory arrest. Normally when we go on bypass and the heart is stopped, the bypass machine perfuses the other organs of the body, and only the heart is ischemic. But in order to work on an empty, still heart, the surgeons must be able to put a clamp across the aorta. If the surgery involves that area of the aortic root and there is no place to put a cross-clamp, then we may do a circulatory arrest. In this case, we cool the body, sometimes even down to 18 degrees. We stop all blood flow and the surgeon has an extremely narrow window of time to create a synthetic aortic root to allow a cross-clamp. Most times, we do not do this under true circulatory arrest because the surgeons place a catheter into one of the arteries going to the brain to allow some selective perfusion. Nevertheless, other than the patient's temperature, the patient's vital signs are essentially nonexistent. But if all goes well, we warm the patient, and that brings them back to life.

A Deficiency in Prolene

Occasionally, we have to take a patient back from the ICU to the operating room to explore a wound, especially if bleeding doesn't appear to be abating. We try to transfuse platelets and coagulation factors, but occasionally the problem is simply a lack of prolene - that is, suture - and the solution is to go back in and sew up the bleeding vessel.

One of the other interesting cases I've had dealt with extracorporeal membrane oxygenation. ECMO is very similar to cardiopulmonary bypass, only it can be maintained in the intensive care unit. While this is more commonly done in neonates, we occasionally try it for adults to weather them through severe injuries by taking over the function of the heart and lungs.

The Weekend CABG

Coronary artery bypass grafting is one of the simpler cardiac surgeries and is rarely an emergency. In patients with multi-vessel coronary artery disease, the surgeon takes veins from the leg or an artery from the chest to bypass the obstructions, allowing bloodflow distal to the blockages. While taking weekend call on this rotation, I have had two scheduled CABG surgeries.

I don't mind doing cases on the weekend, and indeed, it is from these two bypass surgeries that I became more and more independent with cardiac anesthesia. However, I wanted to write a post about the drive for these surgeries which was financial in nature. Medicine's ideals ask us to be blind to money, but the reality is that money affects everything. The two patients couldn't have been more different, however; one patient was a VIP and the other was an uninsured gentleman in the coronary care unit. For the first, expediting his surgery was a matter of patient preference so he would not have to be in the hospital longer than necessary. For the second, doing the surgery earlier would reduce the cost of ICU care. Of course, the cost argument must be balanced to the fact that staffing operating rooms outside business hours is more expensive.

Is this right? I don't agree with it. I think surgeries should be blind to financial pressures and this means we should be doing more on weekends. Why wait until Monday to do a surgery that can be done Saturday? If an inpatient is medically optimized, then waiting simply incurs more cost and increases hospital complications. It shouldn't just be the rich self-pay patient or the indigent one who cannot pay who get expedited operations. The decision to do something on a weekend should be based on medical circumstance. I understand that no one wants to work on the weekends, and neither do I, but this business is one of doing the best thing for patients, and waiting is no good.

Memorial

Perhaps it is my personal background, but I never knew anyone in the Armed Forces growing up. My first contact with those who had been in the military was as an undergraduate when I volunteered at the local Veterans' Administration. Medical school and residency were my true introductions to those brave men and women who served this country. It gave me a window into the intense experiences they had, how their service forms their identity, and the physical and emotional burdens they carry. The psychiatric and medical accouterments they carry, they carry for life.

Image of Arlington National Cemetery is in the public domain, from Wikipedia.

Point / Counterpoint II

This is a continuation of thoughts from yesterday's post. Despite all these changes that happen in training, I feel that I still make and try to make meaningful connections with my patients. Developing a solid patient-physician relationship is not only related to asking them about their hobbies, pets, and grandparents but also about having the confidence and reassuring presence of a doctor who will accompany someone through a challenging time of their life and make those hard decisions to get them through it. When I see a patient preoperatively, I spend only 10 minutes and my time is constrained by the surgeon's and operating room's desire to start promptly. But I hope that when I grasp a patient's hand as I place the IV, walk them through what to expect, and discuss their medical problems that I come across as warm, unhurried, knowledgeable, capable, and compassionate. I sit if I can. I make those 10 minutes count. And as I roll the patient back to the operating room, I try to get to know them. I want to know where they are from, what scares them about surgery, and what they hope to do once they're better.

Although I can do procedures without hesitating, it does not follow that I am not bothered by hurting someone. Perhaps it is being an anesthesiologist, but I believe there cannot be too much lidocaine (at least subdermally; plus, we can treat lidocaine toxicity if needed). Even in placing an IV, I don't want the patient to feel a thing and numb up the skin, something that doesn't happen in the emergency department or the wards. Pain can and should be treated and I hope I never become so callous as not to care.

And indeed, looking past residency, I find that attendings are able to get to know patients better. Whether because of more time flexibility or more comfort with the medical and technical aspects of anesthesia, they often engage patients in conversation, talk with the families, and really care for people. And outside of anesthesia, attendings develop long-term relationships that grow and flourish over time, a suggestion that we do not become more callous the longer we are in this field.

Point / Counterpoint I

Do doctors in training get callous over time?

Certainly, over the last two years, some things become easier. It is easier for me to put a needle into someone, and indeed, put a knife to skin. I spend less time talking to patients about where they're from, their family, their job, their life. I adhere to time limits I set for myself for difficult family meetings. When I do chest compressions, I push hard and fast.

These are all adaptations necessary to being a resident. As I progress, the demands on my time increase greatly. My responsibilities increase likewise. If making a small cut to place a central line or putting in a large needle to thread an epidural catheter or CPR are necessary, I no longer hesitate.

I remember being a student when I could be in a patient's room for an hour gathering a history. Perhaps a little aimless, my questions would wander the span of their life, and in doing so, uncover a lot that is important, but not medically essential, about the patient. I would arrive at the scene of an emergency and be arrested in panic. My movements would be too reluctant, my hesitancy too pronounced.

Yes, doctors become roughened in this field. We change so as to filter out that information which is not necessary, and then slowly, to dispense with asking about it. We learn to do things that may cause a patient pain or discomfort or harm because we sincerely believe that the patient's health requires it. Is this callous? The counterpoint to this post will come tomorrow.

Support

In cardiac anesthesia, we see invasive and aggressive mechanical support devices. An intra-aortic balloon pump, shown above, is a balloon in the aorta that assists the heart in pumping blood during systole and filling the coronary arteries during diastole. It is timed to the EKG, placed in the leg, and snaked up, almost like the stents from the previous post. Understanding the device, as well as the potential complications, how it works, and when it may help, is essential to providing anesthesia to patients who have them or might get them.

Occasionally, patients have hearts that simply cannot pump blood forward adequately, despite pharmacologic motivation and balloon pumps. We sometimes place ventricular assist devices which act like the heart, sucking blood from the ventricle and pumping it out into the body. Since the device provides most of the work and gives a continuous rather than pulsatile flow, the patient has no pulse. The heart isn't even entirely necessary. Indeed, occasionally the aortic valve is sewn shut (we do this if the patient has an incompetent valve since we don't want the device delivering blood that simply goes back to the ventricle). Simple things like blood pressure, oxygen saturation, and other monitors may not work. Placing lines requires ultrasound guidance. Sometimes these are bridges to patients getting a transplant.

Image of intra-aortic balloon pump is in the public domain, from Wikipedia.

Endovascular Stents

Although I have written mostly about cardiac cases because they are the most exciting and memorable, we cover a lot of vascular cases as well. The smaller ones like varicose vein surgery, amputations, and fistula creation for dialysis are straightforward. But some of the more interesting surgeries include stenting of aortic aneurysms. Aortic aneurysms, weakness in the wall leading to dilation of the vessel, form in elderly hypertensive smokers and can be life threatening if they rupture. In the past, open surgical procedures were accompanied by high morbidity and mortality, but the development of endovascular approaches where the surgeons go up a leg vessel and deploy a graft to stabilize the aneurysm has helped us treat patients who previously had no recourse.

The anesthetic for these is not complicated; surgeries last an hour or two and patients do well afterward. But it's fun for me to be able to see on fluoroscopy the progress of the surgeons and the anatomy of the vessels. Furthermore, for some aneurysms, like those in the thoracic region, we put in a lumbar CSF drain. We don't do this often, but it's not hard because it is simply placing an epidural catheter in the spinal space (rather than the usual epidural space). I believe in the future, more and more high risk surgery will be done with minimally invasive approaches as intravascular valve replacements and aortic stenting become more widespread.

Image of a stent in the abdominal aorta is in the public domain, from Wikipedia.

Ring of Fire

This annular solar eclipse, almost like a ring of fire, is from October 3, 2005, shown under Creative Commons Attribution Share-Alike License, from Wikipedia. I am sure that many pictures will surface of the eclipse today. Astronomy is one of those fascinating and amazing subjects that we know so much about as children but seem to cloister themselves away as we get older. But things like this remind me that there is so much wonder in the world.

Emergency

True surgical emergencies, the kind that have to go immediately, are uncommon. Other than stat C-sections, there are few disease states or injuries that don't even allow five minutes to evaluate the patient, prepare medications, and set up equipment. Even cases like appendectomies, exploratory laparotomies for a perforated viscus, debridement and fixation of an open fracture, etc. allow time for laboratory studies, imaging, and evaluation before going to the operating room.

The other day, however, I had a true emergency. As I was taking my prior patient to the post anesthesia care unit, the anesthesia scheduler told me that a patient was coming up from the emergency room now and that I had to get as much prepared as I could. An elderly gentleman with an unknown history presented with altered mental status. He was found to be tachycardic, hypotensive, and hypoxic with an oxygen saturation of 60%. The emergency department attempted to intubate him, but because of tracheal stenosis, they could not pass a regular size breathing tube, and instead put in a tube that was too small to adequately ventilate him. He needed an emergency tracheostomy, a surgical procedure to put a breathing tube through the neck.

The procedure was really emergent; as the patient rolled in, he had unstable vital signs, and we rushed to get him on the operating table, hook up our monitors, check our IV access, and prep the neck for surgery. Once the new airway was secured, we were able to oxygenate and ventilate the patient. This case taught me the priorities for an emergent case; here, the surgery was the definitive solution and nothing should delay that. From an anesthesia standpoint, my priorities were trying to oxygenate and ventilate the patient, supporting the blood pressure, and checking my IV access and monitors. Once these were satisfied, I had to ensure amnesia and give antibiotics. I didn't have the usual luxury of time and planning, but identifying the most important steps were critical to the anesthetic.

To Know Someone

When I chose anesthesiology, I was afraid that I wouldn't really get to know patients. And indeed, I don't know them in the sense that their primary care doctor or pediatrician might. I might not know their nickname or their job or what their kids do or why controlling diabetes is so hard for them. Patients may not confide how many drinks they really have each night or that they feel depressed all the time. I don't spend as much time examining each patient. I don't follow up after each surgery to learn how it has impacted their life. In these ways, family doctors, psychiatrists, surgeons, obstetricians, and specialists know patients better than I do.

But since starting residency, I've realized that I know a lot about patients in other ways. In taking control of their breathing, in supporting their heart during surgery, in titrating pain medications, in running my hands up and down their arms looking for a vein, in looking at their heart with an echocardiogram, in following the surgeons' progress, in reassuring a patient pre-operatively, in making sure they will do fine post-operatively, I have learned a lot about the patient and their body. I know how they react under stress. I can predict how their recovery will look. I know what will save them in an emergency. It's a different kind of knowing, but just as important, and just as fulfilling.

The Young Heart Patient

For the most part, cardiology is a geriatric specialty. Heart disease is a process that occurs over decades, and age is one of the strongest risk factors for coronary artery disease. Most of the patients I saw with heart attacks last year and who are getting coronary artery bypass surgery this month are over 60. However, there are a few rare disease states in which young people require heart surgery. Genetic syndromes like Marfan's disease predispose to aortic dissections because the vessel wall weakens over time. I had a young patient who already had her aortic root and aortic valve replaced, but who continued to have a chronic dissection of the aorta and required a revision. It was a very long surgery with over 8 hours on cardiopulmonary bypass, but luckily, the patient's reserve being otherwise healthy and young pulled her through.

Myocardial bridging is one of those newer diagnoses that I have mixed feelings about. In myocardial bridging, the coronary vessels go through the heart muscle rather than on top of it. It's seen in the general population at a reasonable frequency on autopsy, exists at birth, and presents with chest pain. In the past, we didn't have the technology to diagnose it so we didn't do anything about it, but now, we're starting to operate on young adults with symptoms because we can see it on cardiac cath. Patients tend to do fine since it's a small surgery in the world of cardiac interventions, but I wonder if it's overdiagnosed now compared to the past.

Spectrum of Heart Surgeries

When I do a pre-operative evaluation for a cardiac patient, I naturally focus on the heart. What is the pathology? The EKG results? The echocardiogram? The cardiac cath? This helps guide my anesthetic induction, parameters for blood pressure, choice of monitors, and vasoactive drips. However, everything else matters too. In the last month, I've seen the gamut of outcomes from cardiac surgery. I did a 3 vessel coronary artery bypass graft the other day and an aortic valve replacement today in relatively healthy patients with no surgical complications or delay. The bypass time was minimal, and the patients did spectacularly. This is the way surgery should be; the patients are extubated quickly, transferred out of the ICU, and return home in a matter of days.

On the other hand, I had a case with a patient on dialysis, a long standing smoking history, and a bypass time of 8 hours, and that did not go smoothly. The patient received a lot of blood products and needed to be dialyzed. He continued to bleed and had to go back to the operating room to get better surgical hemostasis. He had a prolonged time on the ventilator and a long ICU course. Despite doing everything the best we could, we struggled to get him through the surgery.

I write about this only because it fascinates me that the heart is the most central organ to the body and we focus so much on it, but everything else plays such an important role in how well patients do after heart surgery.

Partner

Aortic stenosis is a condition that limits a patient's activities, causes symptoms like chest pain and syncope, and can even be the cause of death. However, patients with aortic stenosis often have many other comorbidities making open heart surgery and valve replacement highly risky. Some patients have pathology like porcelain aorta that make open valve replacement technically difficult or impossible. In these cases, a new approach called transcatheter aortic valve replacement has been developed. Placed in the femoral artery in the groin and advanced retrograde to the heart under fluoroscopy, these catheters balloon open the tight stenotic valve and replace it with a valve deployed under cardiologist guidance with a transesophageal echocardiogram. The studies involving these transcatheter approaches, called the Partner trials, demonstrated that this new approach may be superior than medical therapy in patients who are not surgical candidates. In the short term, it appears to be a reasonable alternative to open surgery. The complications include vascular damage and strokes, but this approach saves the patient a sternotomy, cardiopulmonary bypass, and the long involved surgery of the open approach.

I recently was able to provide anesthesia for a patient undergoing transcatheter aortic valve replacement. The set-up is quite involved because we prepare to open or crash onto bypass if necessary. We have a large surgical team; along with the surgeons and anesthesiologists, we have the perfusionist for bypass, cardiologists,  an operating room nursing team, a team from the cath lab, and representatives from the company that manufactures the valves. It's a good example of expecting the best but preparing for the worst. The surgery went smoothly; we were done in a third of the time of an open repair, and when I saw the patient that afternoon, he was extubated, shook my hand, and felt hungry. The technology we have to replace a heart valve through a small cut-down in the groin is amazing.

Image of heart valve shown under Fair Use, from heart.bmj.com.

Soiree

The Arts and Anesthesia Soiree from the last post was a smashing success! With over 130 attendees, over a dozen performers, and a dozen exhibits on display, it was an amazing evening. We were lucky enough to have a part of the Arrillaga Alumni Center with delicious catered food, easels, a stage, and a piano. I checked performers in as they arrived and managed the flow of the evening. Our musicians included a jazz duo, a quartet of an attending and her three kids, a couple pianists, and a flautist. Singers included an amazing R&B anesthesia tech (who has a YouTube channel) and a choral group. We had a handful of poets and a collection of miscellaneous talent: a short film, ballroom dancers, and martial artists. On display, we had some impressive photographs (from many contributors, some printed, some digitized on powerpoint). There were some origami pieces, sketches, handmade dresses, paintings, and even a collection of knitted vegetables. It was such a fun night and I really appreciate the department's support of our talents, hobbies, and passions outside of work. Emotion is the wellspring of art, and it's so important to share and cherish this facet of life.

Arts and Anesthesia

I'm part of the organizing committee for the Stanford Arts and Anesthesia Soiree, a showcase of department talent in the arts - from music to photography to painting to crafts to dance. A handful of us felt that it was important to put together an event bringing together the department in a forum outside of work. It happens tomorrow at 5:30pm at Arrillaga Alumni Center.

Image taken by one of our artists.

Coagulopathy

One of the other aspects of anesthesia for heart surgery is understanding and managing bleeding. The amount of time a patient is on bypass, especially if it is over 3 hours, correlates with the amount of coagulopathy. Since we do a lot of complex surgeries on multiple valves or the aortic arch, we often have very long bypass runs. As blood goes through the artificial heart-lung circuit and as the body cools, the effectiveness of platelets decreases dramatically. As the surgeons get into bleeding and transfusions are given, the proteins necessary to form clot are depleted.

As a result, at the end of long cases, I've given tons of product - units after units of platelets, fresh frozen plasma, cryoprecipitate, and blood. In extreme circumstances, we consider newer, expensive medications like recombinant factor 7 and FEIBA, a factor complex mostly used in hemophilia. As a resident, I also learn about dynamic measures of bleeding and clotting such as thromboelastography, a test only used in anesthesia and surgery. Even if I don't go into cardiac anesthesia, learning and experiencing this is important because the same principles apply to severe trauma or critically ill patients.

Image of platelets is in the public domain, from Wikipedia.

The Ultimate Back-Up

To some degree, anesthesiology is about back-up plans. Even though my days almost always proceed ideally, I plan and prepare for the worst. The alert and vigilant anesthesiologist thinks of worst case scenarios: what if the patient has an allergy to this medication? What if the IV becomes dislodged? What if the surgeons get into unexpected bleeding?

Cardiac anesthesiology introduces me to the ultimate backup, which is really only available to this specialty: cardiopulmonary bypass. All of the most dreaded anesthetic emergencies - a heart attack, refractory arrhythmias, persistent hypotension, inability to oxygenate the patient - can be temporized by putting the patient on a heart-lung machine. Of course, bypass and the amount of time on bypass has its risks, so once the patient is rescued, we have to work quickly to reverse the problem.

This became extraordinarily clear to me during a surgery on a patient who had multiple prior operations on his heart. In the same way our body scars when we get cut, each surgery creates more and more scar tissue, which can be extremely worrisome if the heart scars to the underside of the breastbone. In order to enter the chest, the surgeons cut through the breastbone with a median sternotomy, and if the heart is stuck to that surface, they can cut open the heart.

Unfortunately, this happened. The thin-walled right ventricle was cut during the sternotomy, and we had to crash onto bypass. Even in such dire circumstances - akin to being stabbed in the heart - we remained calm. The surgeons, anticipating this possible complication, had already prepped and dissected to the femoral vessels in the leg. I was equally prepared and began transfusing blood and giving heparin to go onto bypass. We were on the heart-lung machine within minutes and despite profuse bleeding from the injury to the heart, we never dropped our blood pressures. Once we were on cardiopulmonary bypass, the surgeons were able to finish dissecting to the heart, repair the laceration, and continue the operation.

Hippocratic

One of the reasons I could not do surgery is that a surgeon needs to have the confidence that when he operates, he will make the patient better. Of course this is true with any medical intervention but in cardiac anesthesia, I see the extremes. When I see a surgeon cut open the heart or slice away a diseased valve I am awed that he has the assurance that he can repair the heart or rebuild the valve such that when we come off bypass, the heart will beat again.

Monitors

The anesthetic plan for a cardiac surgery needs to take into account all the possible things that could go wrong and what we'd need to treat the patient. As most patients have coronary artery disease, valve disorders, or aortic pathology that requires tight control of blood pressure, we place an arterial line for blood pressure monitoring before the patient goes off to sleep. After intubation, we usually place multiple large bore IVs in case there is severe blood loss requiring lots of fluid or transfusion. In the neck, we usually place a large introducer to aid in volume resuscitation as well as a multi-lumen catheter for drips. In some cases, we place a cerebral oximetry monitor to make sure the brain is being perfused or a pulmonary artery catheter to measure cardiac output and monitor pulmonary artery pressures.

All of this preparation takes a good amount of time and when I started the rotation, I would routinely bring in the patient at 7 and hand them off to the surgeons around 8. Today, I was extremely pleased; we were ready for our 3 vessel coronary artery bypass surgery at 7:18AM. As with everything, planning and preparation as well as practice makes everything smooth.

Unhusking

I got to provide anesthesia for a fairly fascinating disease the other day. The heart is encased in a thin veil of tissue called the pericardium. Normally, this is very compliant, meaning that if the heart wants to expand, its vestments permit it to. However, there is a family of disease states that involve the percardium or pericardial space (between the pericardium and the heart muscle). The most dramatic of these diseases is cardiac tamponade where fluid or blood accumulates in the space outside the heart and within the pericardium. The heart, not used to external pressures and confinement, struggles if this fluid accumulates quickly; even 50mL of fluid can be life threatening. As this fluid is trapped in the pericardial space and cannot go anywhere, all it can do is compress the heart.

On the other end of the spectrum is chronic constrictive pericarditis, which was the disease I saw a few days ago. In this case, the elastic sac around the heart becomes scarred and tight from radiation, infection, or old cardiac surgery. The heart's volume becomes fixed and the left and right sides have to share the space. Indeed, all the pressures within the pericardium equalize at parts of the cardiac cycle, a hallmark sign. The heart, unable to fill easily, fails.

It's remarkable to see this heart on the echocardiogram and then visually when the surgeons open the chest. It struggles, but when the surgeons release the fibrotic tissue, stripping the pericardium away from the heart, it jumps back to life (indeed, they do this surgery without stopping the heart, which is amazing). It's a delicate task as the pericardium is often scarred onto the heart, so the surgeons have to carefully dissect the outer layer from the rest of the muscle. It is akin to peeling a grape.