Effect of post-perfusion hyperoxemia on early graft function in renal transplant recipients: a retrospective observational cohort study.

Background: The effects of hyperoxemia on the transplanted grafts arouse interest nowadays, particularly intraoperative hyperoxemia, on transplant kidney function and survival in the 1-year post-operative period.

Aims: We aimed to investigate the effect of post-perfusion (5 min after perfusion) hyperoxemia on early graft function and survival in renal transplant recipients.

Methods: Two hundred forty-seven living donor kidney transplant recipients were included in the study. Patients were divided into the three groups according to their partial arterial oxygen pressure in post-perfusion blood gas samples: group 1: normoxia (n = 52, PaO2 pressure: < 120 mmHg, 103 ± 13); group 2: moderate hyperoxemia (n = 121, PaO2: 120-200 mmHg, 169 ± 21); group 3: severe hyperoxemia (n = 74, PaO2: > 200 mmHg, 233 ± 25). Graft functions (serum creatinine levels, estimated-glomerular filtration rate values, spot urine protein/creatinine ratio), survival rates, and groups' clinical outcomes were compared in the first year after transplantation.

Results: Graft survival rates were similar in the groups and the rate of BK virus viremia was the lowest in the group 3 (groups 1, 2, and 3: 15.4% (n = 8), 6.6% (n = 8), 1.4% (n = 1), respectively, P: 0.009). Serum creatinine and proteinuria levels were lower, and estimated-glomerular filtration rate values were higher in group 3. A negative correlation between partial arterial oxygen pressure and serum creatinine levels and a positive correlation with estimated-glomerular filtration rate value were noted. These results were confirmed by univariate and multivariate analyses.

Conclusions: We demonstrated that the kidney transplant recipients with post-perfusion hyperoxemia have better early graft functions and lower BK virus viremia rates.

Trial Registration: ClinicalTrials.gov Identifier: NCT04420897.