['During sequential double-lung transplantation (DLT), the newly implanted first lung receives the entire cardiac output during the implantation of the second one. This may be responsible for the increased hydrostatic pressure that causes severe interstitial and alveolar edema that can lead to allograft dysfunction. The authors tested the hypothesis that CPB started after first graft implantation and before second recipient lung removal should improve post-transplantation oxygenation and clinical outcomes.', 'Observational during 2 consecutive 1-year periods.', 'University hospital.', 'Nine consecutive patients undergoing sequential DLT with CPB started after first graft implantation and before second recipient lung removal were compared to controls, who were 10 consecutive patients who underwent sequential DLT but without CPB the year before.', 'Oxygenation after transplantation was assessed. The use of CPB during the implantation of the second lung was associated with an increased mean postoperative ratio of PaO2 to the fraction of inspired oxygen at 1 hour (363±51 v 240±113, p = 0.01) and 6 hours (430±111 v 280±103, p = 0.03). The mean duration of CPB was 111±19 min. The occurrence of primary graft dysfunction and the need for extracorporeal membrane oxygenation tended to be lower, but did not reach significance. Similarly, mortality rate was comparable between both groups, as was the rate of blood transfusions.'] Does cardiopulmonary bypass during a second-lung implantation improve postoperative oxygenation after sequential double-lung transplantation?