Lung transplants: An anesthesiologist’s vigilance

It’s 3 a.m., and an experienced hand gently squeezes the first breath into a patient’s newly perfused lung.

Doctor Reust viewing monitors in the operating room

On lung transplant time, vigilance is the defining word for anesthesiologists. While cases can start at any time of day, preparations often begin 8 to 12 hours in advance. Myriad uncertainties from a variety of factors define these high-pressure procedures. But once it’s go time, it’s the anesthesiology team that stands vigil, sometimes for 8, 10, or 14 hours at a stretch late into the night or early into the morning, dosing and redosing, monitoring and testing, ensuring the patient’s safe passage.

This year, UF Health Shands Hospital is on target to perform over 100 lung transplants. As of January, the program’s one-year postoperative survival rate was ranked the best in the country at 98%, almost 10% higher than the national average, according to the Scientific Registry of Transplant Recipients. Similarly, the waitlist mortality rate is extremely low at 4%, versus the national average of 18%, which is one of the lowest in the country. The waiting time to transplant was an impressive average of only 1.2 months

As of March, UF Health had already performed 15 double-lung transplants in patients whose lungs were irreversibly damaged from COVID-19 infection. UF Health is one of only a few elite institutions in the country to have performed COVID-related lung transplants.

So many healthcare providers and services are essential to the success of lung transplants, including teams of subspecialty-trained physicians, highly skilled nurses, perfusionists, ECMO specialists, surgical technicians, respiratory and physical therapists, and transplant coordinators. For anesthesiologists, these procedures are among the most challenging and demanding of all anesthesia cases. To better understand the role of anesthesiologists, we shadowed an attending for a recent double-lung transplant.

No room for error

The running mantra is that lung transplants rarely happen during daylight hours. For the anesthesiology residents, technicians, and many others working behind the scenes, these procedures begin hours earlier than the scheduled time, with allocating resources and meticulously setting up the operating room. Much like preparing to fly an airplane, there is no room for error.

On this transplant day, third-year resident Sam Searcy, MD, is setting up the operating room while juggling coordination of cases in another tower. The anesthesia team, including residents and fellows, is responsible for allocating resources to the transplant case, which by its unpredictable nature makes it emergent, in addition to anesthesia services across three towers.

Doctor Reust instructing a resident

On this transplant day, the attending is Daryl Reust, MD, an Assistant Professor of Anesthesiology in the Division of Cardiothoracic Anesthesia with a background in electrical engineering and meticulous attention to detail. Along with fourth-year resident Emily Li, MD, who is assigned to the case, Dr. Reust spends much of the morning setting up the room, scrutinizing the patient’s medical records, and visiting the patient for additional ultrasound imaging in preparation for the placement of special IVs required for these cases. Transplant recipients undergo a battery of tests to assess their organs. While patients must be sick enough to be considered for transplant, they must also be well enough to withstand the induction phase, operation phase, and lengthy recovery period.

Today’s case is a patient scheduled for double-lung transplant with the assistance of a heart-lung bypass machine known as extracorporeal membrane oxygenation (ECMO). COVID-19 has damaged the patient’s lungs severely enough to require transplant, and as a sustaining measure, the patient underwent a tracheostomy and was placed on ECMO. The machine is frequently the only option for some of the sickest patients. ECMO takes the patient’s blood outside of the body to oxygenate it prior to pumping it back to the human body. This patient’s lungs were irreversibly scarred to the point that they could no longer perform the function of inhaling oxygen and exhaling carbon dioxide. ECMO can also be used to support the heart when it fails because of a backup of pressure from acute or chronic lung disease.

“Double-lung transplantation at UF has burgeoned because of surgical and anesthesiology leadership, but the teamwork employment of early and aggressive intraoperative ECMO has revolutionized our ability to complete these operations with reduced stress on the recipient’s heart and new lung (once it is allowed to work),” said Bruce Spiess, MD, FAHA, Professor of Anesthesiology and Associate Chair of Research. “The interaction of the surgical team, perfusionists running the ECMO technology and anesthesia team must be minute to minute to assure the best outcome for the patient.”

For the anesthesiologist, ECMO presents additional considerations, including an increased risk of blood clots. Inflammation, which is one of the body’s responses to threats from diseases like COVID-19, has strained the patient’s other organs, including the kidneys. All of these factors must be monitored and dynamically managed throughout the operation.

With transplants, one of the main concerns is protecting the right heart from decompensation; anesthesiologists must constantly calculate a patient’s reserves and assess the risks and benefits of each drug as they manage hemodynamics, correcting without overcorrecting.

“Everything must be weighed and measured,” Dr. Reust said. “Induction of anesthesia is probably the most challenging time and the least predictable in how patients will respond. You have to be as strategic as possible and be ready to respond immediately in case of an unfavorable response.”

For Dr. Reust, who is also board certified in echocardiography, one of the appeals of cardiothoracic anesthesia is the many stages. “Cardiothoracic anesthesia has so many facets, which require constant shifts in anesthetic management,” he said.

A team-based approach

In the Department of Anesthesiology, the Division of Cardiothoracic Anesthesia providing services for lung transplants includes Yong G. Peng, MD, PhD, FASE, FASA, Chief of the Division of Cardiothoracic Anesthesia; Michael Arnold, DO; Melissa Burger, MD; Laurie Davies, MD; Michael Franklin, DO; Gregory M. Janelle, MD, FASE, FASA; Todd E. Jones, MD; Edward McGough, MD; Andrew Pitkin, MBBS, MRCP, FRCA; Albert Robinson III, MD; Dr. Reust; and Dr. Spiess.

Many of these faculty anesthesiologists who devote their specialized skill sets to these complicated procedures have completed fellowship training in cardiothoracic anesthesiology as well as specialized training in the interpretation of echocardiography. Anesthesiologists bring this expertise to the team-based approach to lung transplants, which begin with a review of every patient by UF Health’s medical review board. The board includes specialists from numerous areas, including dieticians, physical therapists, social workers, psychiatrists, psychologists, pharmacists, thoracic surgeons, and pulmonologists. The team thoroughly assesses a patient’s suitability for transplant, considering the whole picture and deciding as a group how to overcome obstacles and prepare for challenges.

“The most important aspect is the team dynamic,” said Dr. Jones, an Assistant Professor of Anesthesiology who has served as the Department of Anesthesiology’s representative on the medical review board for lung transplants for the past two years. “Everyone’s expertise is valued in this team setting, which is essential to ensuring the best outcome for our patients.”

Absolute precision when seconds count

Transplant time is fluid until the donor’s lungs become available. When the blood flow is stopped, the clock starts ticking. Lungs, unlike other organs, poorly tolerate long periods without blood flow. Six hours is considered the upper limit for safe ischemic time in lung transplant, and seconds matter. The organs often must travel by ground to a local airport, by air to Gainesville, and again by ground before they can be sewn in; it is imperative that the surgeons can start well before the lungs arrive. The next window is critical for anesthesiologists, who are required to safely yet expeditiously induce general anesthesia and place multiple invasive monitors before the operation can begin.

Intubation, or placing the breathing tube, as a matter of course can be risky and difficult, with the possibility of aspiration, hypoxia, or cardiac arrest. The anesthesiologists use a special breathing tube that allows them to separate the patient’s lungs and breath on one side at a time or with both lungs depending on the stage of the procedure and the needs of the surgeon. Absolute precision is required: Millimeters can make a difference in placing an endotracheal tube. To help confirm the exact location, anesthesiologists use a bronchoscope, a thin tube with a flexible fiberoptic camera that can maneuver around small corners in the trachea and airways.

The anesthesiologists also place a large-bore double-lumen central line in the jugular vein that is roughly the size of a pencil, through which another catheter is placed and floated through the right side of the heart and into the pulmonary artery to measure pulmonary artery pressures, blood oxygen levels, and flow. This is critical because most end-stage lung disease are concomitant with pulmonary artery hypertension, which can lead to circulatory collapse if not precisely managed during the lung transplant induction phase.

A transesophageal echocardiography (TEE) probe is placed into the esophagus to monitor heart function and ongoing volume changes. Intraoperative TEE is critical during lung transplant, alerting anesthesiologists to dangerous events such as hypovolemia, right ventricle decompensation, and emboli so that they can make rapid therapeutic interventions. In addition to cannulation for invasive line placement, anesthesiologists immediately begin administering immunosuppressant drugs to prevent the patient’s body from rejecting the new organs.

Staying the course

Doctor Reust administering intravenous medications

For the next 8 to 10 hours, the anesthesiologists will continue this highly coordinated dance, administering countless intravenous medications and fluids to balance hemodynamics while monitoring the patient’s heart function, blood pressure, fluid output, and vital functions through imaging and testing, all while ensuring that the patient remains comfortably unaware of a “clamshell” incision that extends horizontally across the middle of the patient’s chest between the ribs and across the breastbone. The anesthesiologist uses the bronchoscope to show the surgeons the inside of the bronchus when reconnected.

When the surgeons complete the reconnections of each new lung, blood flow and ventilation is re-established. It is then the anesthesiologists’ job to re-expand the new lung, breathing by hand for several minutes using a self-inflating bag separate from the ventilator under the team’s watchful eyes. After assessing how the new lung performs, it is connected to the ventilator and the surgeons begin working on the second lung.

Even when blood flow has been restored to both new organs, the patient’s breathing tube must be exchanged for a different size and type specialized for postoperative care before the patient is transferred to the intensive care unit while comfortably sedated. After that hurdle has been cleared, transplant pulmonologists and critical care anesthesiologists work together to provide ongoing high-level care with the assistance of the multidisciplinary critical care team.

“The anesthesiologists carry a heavy load to provide comprehensive, focused, and dynamic care throughout the many hours during lung transplantation to ensure the quality of care that has to be there for our patients,” Dr. Reust said.

There may be a long road to recovery ahead, but the anesthesiologists have performed an integral role in seeing the patient through the critical procedure, leading the way to an opportunity for a new life.