Lung Transplant - Post-operative Monitoring

After lung transplant

Recipients, after lung transplantation, are treated with three types of anti-rejection drugs (immunosuppressants). These are: cyclosporine or tacrolimus, azathioprine or mycophenolate, mofetil And prednisolone. In most centers, then, patients receive post-operative prophylaxis against cytomegalovirus (CMV) infection with antiviral drugs.

Patients have their mechanical respirator removed as soon as possible after lung transplantation. Immediately after extubation and awakening, they are encouraged to walk as soon as possible. Within 48 hours of transplantation, patients undergo a bronchoscopy (examination that consists in direct observation of the bronchi through a flexible tube equipped with a camera introduced for nasal route), control to evaluate the correctness of the transplant and to identify possible infections. The primary goal of post-operative management is the prevention of acute rejection, infection control and monitoring of renal and hepatic function. Patients are then subjected to other surveillance bronchoscopies at 2 weeks, 1 month, 2 months, 3 , 6 and 12 months after surgery.
The follow-up (close control of the operation) after a lung transplant is extremely complex and requires a high level of cooperation from the patient. The main objective is to avoid, recognize and treat all complications in advance. Apart from the patient's cooperation, regular examinations, contact with the transplant center, chest x-ray examinations, laboratory tests, pulmonary function tests and bronchoscopies are also essential. In the initial phase, lung function usually improves continuously and reaches a plateau (state phase) after about 3 months. Then, the values vary only slightly. A decrease in lung function value of more than 10% may be indicative of a serious problem such as rejection, infection, airway obstruction, or obstructive bronchiolytic syndrome (BOS). To diagnose a transplant complication early, some centers recommend evaluating the spirometry at home: the patient is in fact discharged in possession of a spirometer issued by the hospital, and has the task of checking his spirometry twice a day and contacting the center in case this was abnormal.

Organ dysfunction after transplant

In the initial phase of lung transplantation, there may be a dysfunction of the transplanted organ (initialed as PGD), characterized by diffuse and visible lung infiltrations, but not always, by conventional Computed Tomography and, only if very numerous and severe, by radiography of the Chest.

PGD occurs in 11-60% of patients; its development in the early postoperative period would adversely affect their long-term survival. Researchers found that PGD, in its most severe form, exposes patients to a high risk of mortality after transplantation, therefore it is necessary to increase the period of intensive care and the days of post-operative hospitalization.
For the evaluation, classification and definition of PGD, many scholars have thought they could use a new high resolution computed tomography, called HRCT (High Resolution Computer Tomography) or MSCT (Multi-Slice Computer Tomography), which is capable of performing tomographic scans (ie to scan and represent, thanks to X-rays, extremely thin "slices" of portions of the human body) at high resolution. Its use has been tested and approved in studies on cystic and pulmonary fibrosis, and on chronic obstructive bronchitis with or without pulmonary emphysema, in which it has proved to be an extremely useful tool for characterizing the disease.

However, the use of this new machine on PGD has not yet been sufficiently tested to monitor the first phase, the most critical one, after a lung transplant, even if the results seem promising and it is thought, in the very near future, to In fact, the pulmonary structure anomalies visible on CT scan are closely linked to the severity of the disease, and it is therefore recommended, to evaluate PGD, to consider the use of HRCT. The scan plane with HRCT (or MSCT) that you plan to use after a transplant is shown in the Table 2.
It has been shown that even the smallest airways can be optimally visualized using this technique, thanks to the machine's ability to produce high resolution scanner overlays from 0.5mm to 1-2mm thick. whole chest. The advantages of HRCT are represented by the fact that even small details are available and the ability to distinguish areas of lung parenchyma that show different pathological pictures. A potential disadvantage, however, is given by the exposure of patients to high doses of radiation.

Table 2 - MSCT scan plane

First MSCT: Third day post lung transplant: Major lung changes are expected at this time.

Second MSCT: Fourteenth day post-transplant. Biopsies will be done before the scan in order to avoid artifacts. Most patients with PGD will have a normal chest X-ray, while clear morphological changes in lung tissue will be observed with MSCT.

Third MSCT: Three months post-transplant: Most patients have achieved stable lung function, near the maximum achievable after transplant. Thus, at this stage, the risk of developing PGD is now out of date.

Fourth MSCT: Twelve months post-transplant. Patients will be fairly stable so any changes found to the lungs at this time will most likely be chronic.