Hemodialysis Effect During Ex Vivo Lung Perfusion

Prolonged lung preservation by ex vivo lung perfusion (EVLP) is an important objective in lung transplantation. Maintaining stable perfusate composition is key, and integrated dialysis is a potential method. We examined the suitability of integrated hemodialysis with EVLP to maintain perfusate homeostasis and extend perfusion time.

Lungs were procured from 30- to 40-kg Yorkshire pigs. The clinical-grade TransMedics OCS Lung system was used with perfusate consisting of autologous washed red blood cells and TransMedics OCS solution. Hemodialysis was added to the venous return line of the device and begun 1 hour after the start of perfusion. Physiological variables and blood gas data were monitored during perfusion, and perfusate cytokine levels were evaluated at prespecified times.

Hemodialysis moderately stabilized electrolyte levels and reduced lactate, but promoted the more rapid development of edema, resulting in shorter mean preservation time in (control [n = 8] vs hemodialysis [n = 6]: 24 hours vs 7.5 hours, P = .034). Using a high-sodium dialysate (n = 5) reduced edema formation but did not significantly extend lung preservation. Notably, significant upregulation of interferon-γ (P < .001) and interleukin 8 (P = .005) was observed in this group, as well as upregulation of the anti-inflammatory cytokine interleukin 10 (P = .0037).

Integrating hemodialysis into an EVLP circuit was detrimental to graft preservation, leading to progressive edema and reduced graft survival. Despite stabilizing circulating electrolyte concentrations, adding dialysis resulted in proinflammatory cytokine upregulation, further reflecting declining graft viability. These findings demonstrate the standard hemodialysis protocol is inadequate for perfusate reconditioning during long-term EVLP, requiring modification for this application.