Objectives: Deceased lung donation requires optimum donor care, with lung viability greatly affected by the progress of the disease leading to brain death. In this study, we searched for causes of lung unsuitability for transplant in both primary and secondary evaluations.
Materials and Methods: Primary lung evaluations included chest radiography, oxygen challenge test, and donor clinical and history examination. Secondary evaluations for lungs that passed the first step included fiberoptic bronchoscopy and donor-recipient matching.
Results: From 2012 to 2017, there were 1020 potential deceased organ donors in our center. Primary evaluations showed that the most prominent reason for lung donation unsuitability was low oxygen challenge result (n = 433, 42.5%). Other reasons were abnormal chest radiograph (n = 378, 38%), history of heavy smoking and inhaled drugs addiction (n = 112, 11%), prolonged intubation (n = 28, 2.7%), and lung disease history (n = 69, 6.7%). There were 104 (10.1%) potential donors to undergo fiberoptic bronchoscopy for further lung evaluation, with 47 (45.2%) selected for final lung donation. Five lungs (4.8%) with bronchoscopic confirmation for suitability were not retrieved due to lack of instruments and resources. Among the 57 (54.8%) rejected potential lung donations, the greatest factor impacting suitability was observation of purulent secretions in bron-choscopy (n = 24, 23%), evidence of aspiration (n = 10, 9.6%), infiltration (n = 7, 6.7%), and tracheitis.
Conclusions: The most common cause of lung rejection after primary evaluation is observation of purulent secretions in tracheobronchial tree. Therefore, implementation of appropriate strategies to prevent respiratory infection in the intensive care unit is needed to expand the lung donor pool.
Key words : Brain death, Chest radiography, Fiberoptic bronchoscopy, Organ donation
Significant improvements have been recently made in the field of lung transplantation. Better pretrans-plant and posttransplant care, novel immunosup-pressive agents, and modern surgical techniques have led to better short-term and long-term survival of marginal-quality or below-optimal-quality lungs from deceased donors.1-3 In addition, new approaches have been established to enhance performance of donated lungs before transplant surgery. Ex vivo lung perfusion, proper antibiotic therapy protocols, use of steroidal drugs,4-6 and better donor recruitment criteria are among the strategies taking place before transplant. Despite these efforts, the rate of lung donation suitability is still low compared with other organs.6
Regarding donor lung selection criteria, less strict criteria have emerged, with acceptance and tolerance of looser physiologic and social parameters. These include arterial partial oxygen pressure/fraction of inspired oxygen ratio, smoking history, donor age, and results of microbiological studies.7,8 However, major bronchoscopic findings, such as evidence of aspiration and suppurative secretions, should not be neglected.9 In this study, we searched for causes of lung donor unsuitability for transplant regarding both primary and secondary evaluations within modern selection criteria.
Materials and Methods
Primary lung evaluation included chest radiography, oxygen challenge test, and donor clinical and history examinations. Secondary evaluations for lungs that passed the first step included fiberoptic bronchoscopy and donor-recipient matching. Underlying causes of rejection of donor lungs within each evaluation were recorded and compared.
From 2012 to August 2017, there were 1020 potential deceased organ donors in our center. Primary evaluations showed that the most prominent reason for lung donation unsuitability was low oxygen challenge result (n = 433, 42.5%). Other reasons were abnormal chest radiograph (n = 378, 38%), history of heavy smoking or inhaled drugs addiction (n = 112, 11%), prolonged intubation (n = 28, 2.7%), and history of lung disease (n = 69, 6.7%). We observed significant mean results of oxygen challenge test in donor lungs that underwent bronchoscopy and those that were rejected (348.7 vs 179.4 mm Hg; P = .01).
A total number of 104 (10.1%) potential donor lungs underwent fiberoptic bronchoscopy for further lung evaluation. Of these, 47 (45.2%) were final lung donors. Five lungs (4.8%) with bronchoscopic confir-mation for suitability were not retrieved due to lack of instruments and resources. Among the 57 potential lungs (54.8%) that were rejected, the greatest factor affecting rejection was observation of purulent secretions in bronchoscopy (n = 24, 23%). Evidence of aspiration (n = 10, 9.6%), infiltration (n = 7, 6.7%), and tracheitis, mass, edema, and erythema (n = 5, 4.8%), as well as lack of instruments and donor-recipient mismatch (n = 10, 9.6%), were other reasons for termination of the lung procure-ment process.
Our results remind us first of the importance of bronchoscopy in final lung donor selection. In other words, without this procedure, about half of the candidates would undergo lung retrieval despite containing a serious pathology. The literature has already shown acceptable evidence regarding the negligible use of gram stain samples and bronchial culture in donor lungs.9-11
Prospective follow-up of donor airway culture and bronchial tissue culture samples have demon-strated a low risk of infection in recipients (< 1.5%).11 These findings are in agreement with 2 other studies that investigated recipient transmission of nonsup-purative bacterial or fungal contamination.9,10 The breakthrough of course has been the recom-mendation of proper antibiotic therapy for Pseudomonas species and Staphylococcus aureus. On the other hand, evidence of frank aspiration has been reported to be problematic for lung donation.12 Therefore, with this finding, it is strongly recommended to place the lungs in the red zone to prevent transmission of infection.
Although radiographic examinations during the donor selection process take place routinely, certain studies have questioned the ability of radiographic studies to reject lungs. Bansal and associates reported a successful and noncomplicated lung transplant from a donor with multiple chest radiographic scans that demonstrated massive lobar atelectasis.13 However, the predictive value of radiographic scans to consider or reject lungs for transplant suitability was not satisfactory according to a retrospective study by Bolton and associates.14 The group reported that diagnostic restriction and variability of interpretation can lead to dissatisfactory results for radiographic scans. Existence of pulmonary infil-trates in plain radiographs has also been discussed as a confounding factor in lung utilization. McCowin and associates challenged radiographic findings by demonstrating that 37% of donors had infiltrates on primary evaluations, 51% of which resolved tho-roughly after specific donor management.15 However, a systematic review recommended that massive bilateral infiltrations in clinically suspicious cases should be an alarm to exclude the donor.16
The most common cause of lung donor rejection after primary evaluation is observation of purulent secretions in the tracheobronchial tree. This could be the result of insufficient donor respiratory care both before and after brain death. Therefore, appropriate strategies are needed to prevent respiratory infec-tions in intensive care units to expand the lung donor pool.
Volume : 17
Issue : 1
Pages : 120 - 122
DOI : 10.6002/ect.MESOT2018.O62
From the Organ Procurement Unit (OPU), Lung Transplantation Research Center
(LTRC), National Research Institute of Tuberculosis and Lung Diseases (NRITLD),
Shahid Beheshti University of Medical Sciences (SBMU), Tehran, Iran
Acknowledgements: The authors declare that they have no sources of funding for this study, and they have no conflicts of interest to declare.
Corresponding author: Farahnaz Sadegh Beigee, Organ Procurement Unit (OPU), Lung Transplantation Research Center (LTRC), National Research Institute of Tuberculosis and Lung Diseases (NRITLD), Shahid Beheshti University of Medical Sciences (SBMU), Darabad, Niavaran, Tehran, Iran 19569-44413
Phone: +98 21 27122103