Subnormothermic Ex Vivo Lung Perfusion Improves Graft Preservation in Rat Ex Vivo Lung Perfusion Model

Abstract

Current standard for organ assessment with machine perfusion before lung transplantation are performed with normothermic temperature. However, subnormothermic condition is already in clinical use with several solid organs. We investigated the impact of subnormothermic perfusion in a rat ex vivo lung perfusion (EVLP) model. Lungs retrieved from 12 outbred Sprague Dawley male rats followed by one hour of cold ischemic storage. All lungs were then perfused in a rat EVLP system for 4 hours. Lung grafts underwent EVLP at two different perfusion temperature (normothermic at 37°C, N=6 or subnormothermic at 28°C, N=6). EVLP physiology and biochemistry were monitored. Oxygenation, pulmonary vascular resistance and dynamic lung compliance were significantly better in the 28°C group compared to the 37°C group (p<0.01) (Figure 1). Potassium ion and lactate concentrations in the subnormothermic perfusion were almost similar with the normothermic perfusion. The tissue ATP at 28°C group showed better ATP preservation than 37°C group. Findings from this preliminary study demonstrated that subnormothermic EVLP might be an alternative to normothermic EVLP in terms of better graft protection. This observation should be validated in large animal model.