Development of a cost-effective ex vivo lung perfusion system for lung transplantation in India

Abstract

Background & objectives: Standard donor lung preservation with cold flush and storage allows up to six hours between retrieval of lungs from the donor and transplantation in the recipient. Ex vivo lung perfusion (EVLP) systems mimic physiological ventilation and perfusion in the donor lungs with potential for prolonged lung preservation and donor lung reconditioning. In this study, it was aimed to perform EVLP on discarded donor lungs using a locally developed EVLP system.

Methods: Equipment that are routinely used for cardiac surgeries were collected and a functional EVLP system was assembled. This system was used on five pairs of lungs retrieved from brain-dead organ donors. The lungs were ventilated and pulmonary circulation was continuously perfused with a solution containing oxygen and nutrients for four hours. The system was tested without red blood cells (RBCs) added to the solution (acellular group; n=3; A1, A2 and A3) and also with RBCs added to the solution (cellular group; n=2; C1 and C2).

Results: The EVLP system was successfully used in four (A1, A2, A3 and C2) of the five lung pairs. Mechanical and gas exchange functions of the lungs were preserved in these lung pairs. One lung pair (C1) worsened and developed pulmonary oedema. Histopathological examination of all five lung pairs was satisfactory at the end of the procedure. Major challenges faced were leakage of solution from the system and obstruction to drainage of RBCs containing solution from the lungs.

Interpretation & conclusions: The results of the present study suggest that, it is possible to maintain the lungs retrieved for transplantation in a physiological condition using a locally prepared EVLP system and a solution without RBCs.

Keywords: Erythrocytes; lung transplantation; organ preservation; organ preservation solutions; perfusate.

Fig. 1

Schematic of an ex vivo lung perfusion setup; LA, left atrium; PA, pulmonary artery; P1, P2, pressure transducers.

Fig. 2

Ex vivo lung perfusion setup in the cardiac surgical operating room.

Fig. 3

Donor lung at the start of ex vivo lung perfusion with the endotracheal tube and cannula in place.

Fig. 4

Parameters measured in the donor lungs during ex vivo lung perfusion; (A) ratio of partial pressure of oxygen in perfusate sampled from left atrium to the fraction of oxygen in the gas given through the ventilator (PO2:FiO2; in mm Hg); (B) Peak inspiratory pressure (in cmH₂O); (C) Mean airway pressure (in cmH₂O); (D) Dynamic compliance (in ml/cmH₂O). EVLP, ex vivo lung perfusion; A1, A2, A3, lung pairs in the acellular group, C1, C2, lung pairs in the cellular group.

Fig. 5

Representative histopathology images from two lung pairs which underwent EVLP; (A) Lung pair A2 at lung recovery from the donor; (B): Lung pair A2 after four hours of EVLP demonstrating scant infiltration of lymphocytes; (C) Lung pair C1 at recovery demonstrating expanded alveoli and scant intra-alveolar macrophages; (D) Lung pair C1 after four hours of EVLP demonstrating mild intra-alveolar and septal haemorrhage. No evidence of ischaemia or thrombosis noted in any of the images. EVLP, ex vivo lung perfusion; A2, lung pair in the acellular group, C1, lung pair in the cellular group.