Utilization of Marginal Lung Donors With Low PaO₂/FiO₂ Ratio and High Body Mass Index

Background: Lungs of donors with high body mass index (BMI) have more atelectasis and a lower PaO₂/FiO₂ (P/F) ratio than those with normal BMI. This study prospectively evaluated outcomes of a new approach for these lungs in our lung transplant program.

Methods: From February 2016 to December 2018, 336 lung transplants were performed at Cleveland Clinic. Of these, 58 met criteria for our aggressive approach to donors with a P/F ratio of less than 300 mm Hg at offer and BMI of 25 kg/m² or greater. In the donor operating room, lung recruitment was performed by positive end-respiratory pressure of 25 to 30 cmH₂O for 30 seconds and lungs were converted to either straight transplantation or ex vivo lung perfusion (EVLP). Postoperative outcomes of the low P/F-high BMI group were compared with those of recipients receiving lungs meeting standard criteria.

Results: Of the 58 donors, 33 were converted to straight lung transplantation because they demonstrated significant improvement in the P/F ratio after lung recruitment compared with the P/F ratio at lung offer (median, 278 versus 420 mm Hg; P < .01). Seventeen lungs with a persistently low P/F ratio underwent EVLP, 8 of which were transplanted. There was no significant difference in primary graft dysfunction grade 3 at 72 hours (n = 3 of 41 [7.5%] versus 31 of 247 [13%]; P = .79) or in 30-day survival (100% versus 97%; P = .60) between low P/F-high BMI and standard groups.

Conclusions: These data suggest that atelectasis in high-BMI donors contributes to P/F ratios less than 300 mm Hg and that intraoperative lung recruitment or EVLP can allow the use of lungs from these donors with good outcomes.