Comparative study of lung preconditioning protocols in donors after circulatory arrest: an experimental rabbit model

Objective : to perform a comparative analysis of donor lung preconditioning protocols in donors after circulatory arrest, followed by normothermic ex vivo lung perfusion (EVLP), using two approaches: topical lung cooling and continued artificial ventilation after circulatory arrest. Materials and methods . The study was conducted on male Grey Giant rabbits weighing 4.5–5.0 kg (n = 20). Group 1: Donor lung preconditioning after circulatory arrest using topical cooling (n = 10). Group 2: Donor lung preconditioning after circulatory arrest with continued artificial ventilation in protective modes (n = 10). To evaluate the viability and functional state of donor lungs following preconditioning and cold preservation, both groups underwent normothermic EVLP. Assessments included lactate concentration, perfusate gas composition, endoscopic evaluation of the tracheobronchial tree, and subsequent morphological examination. Results . After 60 minutes of cold preservation, all grafts demonstrated satisfactory gas exchange function during normothermic EVLP. In Group 1 (topical cooling), the oxygenation index (OI) at 60 minutes was 552 (461–599) and increased to 558 (462–603) at 120 minutes. In Group 2 (continuous artifi cial ventilation), OI was 358 (343–368) at 60 minutes, with a tendency to increase to 374 (349–395) at 120 minutes. The difference between the groups was statistically signifi cant (p = 0.000). Lactate levels in both groups showed an upward trend, with a mean value of 6.99 ± 0.81, and no statistically significant intergroup differences were observed (p > 0.05). Conclusion . The study demonstrates the potential advantages of using topical cooling as part of the donor lung preconditioning protocol after cessation of eff ective circulation, employing a dextran40-based preservation solution at all stages. This approach may increase the number of donor lungs suitable for transplantation.