Influence of high molecular dextrans on lung function in an ex vivo porcine lung model.

Background: Extracellular preservation solutions utilizing high molecular agents can reduce intracellular edema during ischemia/reperfusion in lung transplantation. A solution of 40,000 dalton molecular weight (DMW) has already been clinically established (Perfadex). However, it is unclear whether dextrans of this particular size represent the optimal additive for lung preservation solutions.
Materials and Methods: In a new ex vivo porcine lung model, lungs were each preserved with low-potassium solutions containing 5% dextran with 90,000 DMW (Dex 90) and 160,000 DMW (Dex 160) and with Perfadex (40,000 DMW). After 24 h of cold ischemia, reperfusion was performed employing a roller pump with a pulsatile module. Lungs were perfused with deoxygenated perfusate and ventilated with room air. The oxygenation capacity (Delta pO(2)), peak inspiratory pressure (PIP), and mean pulmonary artery pressure (PAP) were monitored for 60 min. Net weight gain (NWG) and wet-to-dry ratio (W/D ratio) were determined. Free-radical generation was assessed by measuring malondialdehyde (MDA) at 10, 30, and 50 min.
Results: PIP and PAP increased in all groups significantly during reperfusion. However, Dex 160-perfused lungs exhibited significantly higher values than those with Dex 90 and Perfadex. Perfadex showed the highest Delta pO(2) throughout the entire reperfusion, while Delta pO(2) was slightly reduced in Dex 160 and significantly lower in Dex 90. In Perfadex the lowest water content was observed assessed by NWG and W/D ratio. The highest MDA values were observed in Dex 90, followed by Dex 160, while the lowest values were seen in Perfadex.
Conclusions: Preservation of the lung with Perfadex exhibited superior postischemic function in contrast to preservation solutions containing dextrans with a higher molecular weight.