Moderate-Flow Perfusion is Superior to Low-Flow Perfusion in Ex Situ Lung Perfusion

Background Full-flow perfusion during prolonged ex situ lung perfusion (ESLP) results in unacceptable pulmonary edema formation. Clinical ESLP at 30% to 50% predicted cardiac output (CO) supports acceptable physiologic outcomes; however, progressive pulmonary edema still develops. Lower flow rates may provide equivalent physiologic preservation with less edema formation due to reduced hydrostatic pressures. We report our results of moderate-flow (MF; 30% CO) vs low-flow (LF; 10% CO) negative pressure ventilation (NPV)-ESLP with transplantation. Methods Twelve pig lungs underwent 12-hours of NPV-ESLP with 30% or 10% CO (n = 6/group). Three left lungs per group were transplanted post-ESLP and assessed in vivo over 4 hours. Lung function was assessed by physiologic parameters, weight-gain, and pro-inflammatory cytokine profiles. Results Results are MF vs LF (mean +/- SEM). All lungs demonstrated acceptable oxygenation post-ESLP (454.2 +/- 40.85 vs 422.7 +/- 31.68, P = .28); however, after transplantation, the MF lungs demonstrated significantly better oxygenation (300.7 +/- 52.26 vs 141.9 +/- 36.75, P = .03). There was no significant difference in compliance after ESLP (21.38 +/- 2.28 vs 16.48 +/- 2.34, P = .08); however, pulmonary artery pressure (PAP; 10.89 +/- 2.28 vs 21.11 +/- 0.93, P = .06) and pulmonary vascular resistance (PVR; 438.60 +/- 97.97 vs 782.20 +/- 162.20, P = .05) were significantly higher in the LF group. Weight gain (%) post-ESLP and post-transplant was similar between groups (29.42 +/- 5.72 vs 24.17 +/- 4.42, P = .24; and 29.63 +/- 7.23 vs 57.04 +/- 15.78, P = .09). TNF-alpha and IL-6 were significantly greater throughout LF ESLP. Conclusions The MF NPV-ESLP results in superior lung function with less inflammation compared to LF NPV-ESLP.