Special feature: "current status and future development of organ preservation technology" novel techniques for assessing pulmonary function in cellular ex vivo lung perfusion: a republication of the review published in Japanese Journal of Artificial Organs.

Lung transplantation is the definitive therapy for end-stage respiratory diseases. To expand the donor lung pool, ex vivo lung perfusion (EVLP) has been developed for the assessment of marginal donor lungs. However, current evaluation methods remain limited. This study aimed to develop non-invasive imaging and monitoring techniques for the quantitative and early assessment of pulmonary function during EVLP. Three novel approaches were established: (1) lung thermography during the initial reperfusion period to assess pulmonary function, (2) optical oxygen saturation (SaO₂) imaging to assess pulmonary oxygenation, and (3) real-time lung weight measurement as an early indicator of transplant suitability. Lung thermography revealed that lung surface temperature at 8 min after shunt closure was significantly lower in non-suitable cases than in suitable cases (25.1 ± 0.6 °C vs. 27.8 ± 1.2 °C, P < 0.01). Optical SaO₂ imaging demonstrated a strong correlation between lower lobe SaO₂ calculated from SaO₂ imaging and PaO2/FiO2 (P/F) ratio in the lower pulmonary vein (R = 0.855, P < 0.01), with SaO₂ being significantly lower in non-suitable cases. Real-time lung weight measurement showed that lung weight gain increased significantly after 40 min in non-suitable cases compared with suitable cases (51.6 ± 46.0 g vs. -8.8 ± 25.7 g, P < 0.01). These three approaches proved effective for the quantitative and early assessment of pulmonary function during EVLP. This review was created based on a translation of the Japanese review written in the Japanese Journal of Artificial Organs in 2024 (Vol. 53, No. 3, pp. 216-220).