Prone Positioning During Ex Vivo Lung Perfusion Influences Regional Edema Accumulation

Ex vivo lung perfusion (EVLP) is developed to increase the quantity and quality of suitable grafts for lung transplantation. Standardly, lungs are mounted supine with the risk of fluid accumulation in the dorsal regions. Therefore, we investigated the impact of experimental prone position on graft function during EVLP.

Porcine lungs were mounted on a normothermic EVLP for 6 h in supine [S], (n = 7) or prone position [P], (n = 7). Physiology during EVLP was recorded. After EVLP, biopsies were assessed for wet-to-dry weight (W/D) ratios and pathology, broncho-alveolar lavage was measured, and the left lung was computed tomography (CT) scanned.

Physiological parameters were similar between both groups, despite a higher pulmonary vascular resistance in [P] (P = 0.0002). In [S], W/D ratios and CT density of dorsal areas were higher compared to ventral (P = 0.0017 and P = 0.053, respectively). In [P], W/D and CT density between ventral and dorsal regions were similar, meaning that pulmonary edema was distributed more homogeneously throughout the lung. Histology and cytokine levels in perfusate and broncho-alveolar lavage did not differ between both groups.

Prone positioning during EVLP is feasible and leads to more homogenous distribution of interstitial fluid. Supine position resulted in more concentrated edema accumulation in lower dependent regions.