(Part of a series about the Lung Transplant Program at Duke University, in Durham, North Carolina).
3:40 am.. the surgical team keeps working steadily in the operating room as they wait for Dr. Reddy to arrive.. One diseased lung is being readied for removal to make room for the new organ. The anesthesia team maintains the patient’s oxygenation and blood pressure carefully, a delicate balance, using only one heavily damaged lung. The perfusionist stands by, to assist with CPB* (cardio-pulmonary bypass, also known as the heart-lung machine) if needed. [for this particular case – I was not present to witness this portion of the procedure]
at 03:45 we arrive, Dr. Reddy bringing in a wheeled cooler containing the organ. Quickly, Dr. Davis and another surgeon (one of the graduating thoracic surgery fellows) begins preparing the new lung for implantation.
The clock is ticking, and has been running since the moment the organ was removed, in that OR several states away. This is cold ischemia time – time when the organ is chilled, prior to implantation. The cold lessens the tissue damage, but doesn’t halt it completely. This is why organ procurement is such an orchestrated process, and why Dr. Davis is here, operating at 3 in the morning. Once the lung is removed from the icy solution and placed into the chest to start the implantation, the real clock (a wall mounted clock) is started, to keep track of warm ischemia time.
Warm ischemia time is the period during which the lung is being implanted into the recipient. This is when the most damage occurs to the harvested organ, and surgeons use several methods to limit the amount of warm ischemia that occurs. One of the ways they do this by infusing cold solutions intermittently while attaching the lung to the pulmonary arteries and veins (anastomosis) to re-establish blood flow prior to re-attaching the bronchus (the airway). The operating room clock is used to record the amount of warm ischemia so that the surgeons know when to re-infuse the solution and to keep track of the total ischemic time during the operation.
Once the lung is reattached by re-establishing both the blood supply from the recipient to the donor lung, and by connecting the airway – it’s time to re-inflate the lung. This is the most tense period of the operation – as surgeons wait to see if the new lung will function as intended. If not, the patient will be connected to ECMO (see below for more information on ECMO) to supply the lung with oxygen rich blood to prevent further injury. Often patients require ECMO for a short period of time after implantation.
One of the problems with lung transplantation is reperfusion injury, which begins at this point.
“Re-perfusion injury” itself is a generic term describing the injury that occurs to tissue once blood flow is re-established (whether this occurs during a treatment of a heart attack, stroke, organ transplantation or other disease process). A good way to think about re-perfusion injury is that this process occurs as part of the body’s (misguided) attempts to heal itself. Unfortunately, as the name implies – this sequelae of biochemical events results in more damage to the organ(s) itself. Medications are also used during this process to limit the amount of reperfusion injury.
Once the lung is functioning (breathing) and the patient is able to maintain oxygenation, and other vital signs (blood pressure and heart rate) the incisions are closed, and the patient is taken to the intensive care unit. From there, if everything goes well, the patient will be extubated (breathing tube removed and ventilator turned off) and out of bed and walking by the next day. (In lung transplant, like all lung surgeries, early ambulation is critical.)
* ECMO (extracorporal membraneous oxygenation) by veno-venous access, which is a therapy very similar to cardiopulmonary bypass is also available.
Watching Dr. Davis operating is an experience in itself – among lung transplant surgeons, he is a legend along with Dr. Joel Cooper and Dr. Ken McCurry. Dr. Davis, locally known as “Dr. McDreamy” for his classic good looks; with silver blond hair and piercing blue eyes is affable and kind. He was patient with my multiple questions, which is important; as in lung transplant it seems like every answer you discover just leads to another layer of questions.
We’d met before, on one of his visits to the hospital in Virginia where I worked, but I didn’t know him as well as Dr. Shu Lin, who initially extended the invitation for me to visit the Lung Transplant service when I’d expressed interest.
Now here in the operating room, performing one of his many transplants (he’s done around 750 to 800 lung transplants), Dr. Davis was focused, but confident. He remained in tune to his patient underneath all those drapes, noticing every change in respiration, heart rate or blood pressure before anesthesia could bring it to his attention, even during the more delicate portions of the operation. I’d come into this part of the procedure after a long day myself, starting at 2am the previous day in Virginia, then meeting with Dr. Lin, rounding on patients, witnessing several cardiac operations before flying off with Dr. Reddy. It all culminated in the operating room with Dr. Davis more than 24 hours later – watching him operate, and watching the lung struggle to take its first breaths in its new home. Somehow, all tiredness vanishes at moments like this [though it returns with a vengeance.]
In this case – the lung struggled and needed a very short period of ECMO before recovering in the operating room*. During all of this, Dr. Davis was calm, and in control. After a few tense minutes, the lung recovered and ECMO was discontinued. The remainder of the case proceeded uneventfully, and I stumbled home to get a few hours sleep before my formal interview with Dr. Davis the next day. It was, all told – another successful surgery for Dr. R. Duane Davis, the patient and the Duke Lung Transplant Program.
* This is related to the physiological function of the donor lung, and the patient response – and not due to technical aspects of the surgery.
Additional References: (to be updated)
Dr. Joel Cooper – thoracic surgeon who performed first ‘successful’ single and double lung transplants, known as the “Father of Lung Transplant“. The first actual lung transplant was performed in 1963 by Dr. James D. Hardy at the University of Mississippi in Jackson, MS.