A lung transplant replaces one or both diseased lungs with healthy lungs from a deceased donor. This intervention is reserved for patients with end-stage pulmonary conditions when all other medical therapies have failed. Common diagnoses necessitating this procedure include severe chronic obstructive pulmonary disease (COPD), cystic fibrosis, interstitial lung disease, and pulmonary hypertension.
Preparing for the Transplant: Listing and Matching
The process of receiving a transplant begins with an evaluation to determine a candidate’s suitability for the procedure and life-long post-operative regimen. This involves numerous medical tests, including pulmonary function tests, cardiac catheterization, and blood work, alongside psychosocial assessments. Candidates must demonstrate the physical and psychological capacity to adhere strictly to the intensive treatment plan following the surgery.
Once approved, the candidate is placed on a centralized waiting list and assigned a priority score, known in the United States as the Lung Allocation Score (LAS). The LAS estimates both the urgency of the patient’s need and the likely success of the transplant. Factors such as the patient’s diagnosis, body mass index, and need for mechanical ventilation are used to calculate this score, prioritizing the sickest patients who are most likely to benefit.
When a donor organ becomes available, the transplant team is immediately notified, and matching begins based on the recipient’s LAS, blood type, and the size of the donor lungs. The procured lungs must be rapidly transported and implanted into the recipient, typically within six hours, to maintain viability. The recipient is called to the hospital for final medical checks and the administration of general anesthesia before the donor lungs arrive.
The Surgical Procedure: Replacing the Lungs
The operation begins once the patient is under general anesthesia and connected to a ventilator, which will breathe for them during the procedure. For a single lung transplant, the surgeon makes an incision, called a posterolateral thoracotomy, along the side of the chest. A bilateral, or double, lung transplant typically requires a clamshell incision that runs horizontally across the chest, offering access to both lungs simultaneously.
The choice between transplanting one or two lungs depends largely on the patient’s underlying disease. Conditions involving widespread infection, such as cystic fibrosis, generally require a bilateral transplant to prevent the new lung from becoming infected by the remaining diseased lung. For non-infectious diseases like emphysema, a single lung transplant may be performed, often targeting the lung with the poorer function.
During the procedure, the patient may be connected to a heart-lung machine, known as cardiopulmonary bypass or ECMO, which temporarily takes over the function of the heart and lungs, maintaining blood circulation and oxygenation while the diseased lung is removed. The surgeon detaches the main airway (bronchus), the pulmonary artery, and the pulmonary veins from the diseased lung before removal.
The new donor lung is positioned in the chest cavity, and the connections, or anastomoses, are performed. The main bronchus of the new lung is sutured to the recipient’s airway, followed by the connection of the pulmonary artery and the pulmonary veins. For a double lung transplant, this sequence is repeated for the second lung, replacing the lungs one at a time. The chest is closed only after confirming the new lung is properly inflated and functioning.
Immediate Post-Operative Care
Following surgery, the patient is transferred to the Intensive Care Unit (ICU) for close monitoring. The first hours and days involve intensive management to prevent primary graft dysfunction (PGD). PGD is a form of reperfusion injury that occurs when blood flow is restored to the donor organ, and its management involves supportive care and lung-protective ventilation.
The patient remains connected to the ventilator, and chest tubes are placed in the chest cavity to drain any air, fluid, or blood. Monitoring of heart function, blood pressure, and fluid balance is performed using catheters. Pain management is a significant focus, often involving epidural catheters to ensure the patient can breathe deeply and comfortably.
The goal is to remove the breathing tube and ventilator as quickly as possible, typically within the first few days, once the new lungs are functioning adequately. Once extubated, early physical therapy and ambulation begin immediately, as movement helps prevent complications. The initial hospital stay, including the ICU and a step-down unit, generally lasts between two and three weeks, assuming no major complications.
Life After Transplant: Preventing Rejection
The primary long-term challenge after a lung transplant is rejection, where the body’s immune system recognizes the new organ as foreign tissue. This requires lifelong strategies to suppress the immune response. Patients must adhere strictly to a regimen of immunosuppressive medications, which dampen the immune system to prevent it from attacking the transplanted lungs.
Despite medication, acute rejection, a sudden immune response, occurs in a high percentage of recipients, particularly in the first year. Acute episodes are often treatable with a temporary increase in immunosuppression, such as high-dose steroids. The more serious concern is chronic rejection, or Chronic Lung Allograft Dysfunction (CLAD), which is the leading cause of death after the first year and causes a progressive decline in lung function.
To detect rejection early, patients undergo frequent follow-up procedures, including regular pulmonary function tests (PFTs) to measure airflow. The most definitive way to diagnose rejection is through a bronchoscopy with a transbronchial biopsy, where tiny samples of lung tissue are taken for examination. A successful transplant often leads to an improved quality of life, but the commitment to follow-up care and medication adherence remains absolute.