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

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.

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.

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.

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.