Background: The preservation of donor lungs during cold ischemia phase plays an important role in improving the function of lung grafts after transplantation. Donor lungs were conventionally preserved with a method of static inflation during ischemia phase, but how mechanical ventilation would affect lungs during this stage was unknown. This study was undertaken to investigate the effects of mechanical ventilation on donor lungs during cold ischemia phase.Methods: Isolated lungs from 45 rats were randomized into control (CON), mechanical ventilation without positive end-expiratory pressure (PEEP) (MVNP) and mechanical ventilation with PEEP (MVP) groups. During the cold ischemia phase, lungs in the CON group were preserved with a conventional method of static inflation, while lungs in the MVNP and MVP groups were mechanically ventilated with tidal volume (VT) of 7 ml/kg without PEEP and VT of 7 ml/kg with 3 cm H2O PEEP, respectively. After 2 hours, bronchoalveolar lavage fluid (BALF) collected from lungs was subsequently analyzed for surfactant, inflammatory cytokines, and total protein; lung tissues were collected for analysis of morphology and the wet-to-dry (W/D) weight ratio; peak airway pressure was recorded before and after lung preservation to reflect the change of lung compliance.Results: Compared to CON group, the levels of surfactant protein B (SP-B), surfactant protein C (SP-C), total surfactant, and active large aggregates (LA) in MVP group raised significantly (P<0.05); meanwhile, W/D ratio, the lavage concentrations of interleukin (IL)-6, and tumor necrosis factor (TNF)-α in the MVNP group were higher than those in the CON group (P<0.05). In contrast with CON group, lung injury scores were higher in both MVNP and MVP groups (P<0.05); the level of peak airway pressure in the MVNP group was dramatically higher than that in the CON and MVP groups (P<0.05), while there were no differences between CON and MVP groups.Conclusions: Mechanical ventilation during cold ischemia phase with low VT and PEEP promoted the level of lung surfactant, but aggravated lung injuries with no effects observed on lung compliance. Citation: Yue Wang, Wen- Zhi Li. Effects of mechanical ventilation on lung grafts during cold ischemia phase. J Anesth Perioper Med 2015; 2: 146-52. doi: 10.24015/JAPM.2015.0020This is an open-access article, published by Evidence Based Communications (EBC). This work is licensed under the Creative Commons Attribution 4.0 International License, which permits unrestricted use, distribution, and reproduction in any medium or format for any lawful purpose. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/.