Addition of Dialysis to Ex-Vivo Lung Perfusion Maintains Homeostasis and Stability of Donor Lungs: A Pilot Study

Abstract

Ex-vivo lung perfusion (EVLP) maintains marginal donor lungs at body temperature with ventilation and circulating perfusate, allowing for functional assessment prior to transplantation. Prolonged EVLP would allow for advanced time-dependent therapies for donor lung repair and reconditioning. We hypothesized that the addition of a dialysis machine to the EVLP circuit would maintain homeostasis of the donor lung and prolong EVLP duration. Porcine donor lungs (n=3) were extracted and placed on the EVLP platform for 36 hours or until termination criteria (dynamic compliance < 15ml/cmH2O) was reached. Lungs were perfused with an acellular solution and closed atrium, according to the Toronto protocol. A dialysis machine was incorporated into the EVLP circuit with a custom-designed dialysate to continuously dialyze perfusate using continuous venovenous hemodialysis (Fig1A). Physiological function, electrolytes and inflammatory mediators in EVLP perfusate were measured hourly. In this pilot study, dialysis cases were compared to historical controls with similar protocol (n=6). Dialysis successfully prevented an increase in electrolyte levels (Fig 1C) and maintained glucose and lactate levels at baseline (1C). EVLP was prolonged in the dialysis group with a mean duration of EVLP reaching 32±6.93 h in the E+D group compared to 18.67±3.27 h in the historical control group (Fig 1D). Percent lung survival at 24h of perfusion was 100% in the E+D group, while only 20% was seen in historical controls (Fig 1B). Both lungs which survived to 36h of EVLP presented excellent lung function based on assessment by EVLP. Dialysis may preserve lung function and length of EVLP by maintaining homeostasis of the lung. Following the results of this encouraging pilot study, a formal blinded experiment is being performed and is underway.