Evaluation of the oxygenation ratio in the definition of early graft dysfunction after lung transplantation

Objective: Despite the clinical importance of early graft dysfunction, no standardized definition is available. We hypothesized that the arterial blood gas oxygen tension/fraction of inspired oxygen ratio (Pao₂/Fio ₂) would prove to be a useful marker for predicting subsequent outcomes of early graft dysfunction. The aims of this study were to define the prevalence of various ranges of Pao₂/Fio₂ over the first 48 hours after lung transplantation and to evaluate which measurement using the Pao₂/Fio₂ best correlates with the duration of intubation, the length of stay in the intensive care unit, and 30-day mortality, which are important alternative indicators of early graft performance. Methods: A retrospective study was performed that included all 68 bilateral single-lung transplantations at The Alfred Hospital from January 2000 to December 2002. Results: Pao₂/Fio₂ at 6 and 12 hours after admission to the intensive care unit was significantly associated with the duration of intubation (r = -0.44; P < .001 and r = -0.48; P < .001, respectively), and Pao₂/Fio₂ at 6 and 24 hours was also significantly associated with the length of intensive care unit stay (r = -0.38; P = .002 and r = -0.44; P = .001, respectively). Thirty-day mortality was significantly associated with a lower Pao₂/Fio₂ at 6 hours (219 ± 93 vs 306 ± 101; P = .03). Conclusions: Pao₂/Fio₂ taken between 6 and 12 hours after transplantation is a useful marker associated with lung transplantation outcomes. There is the potential for therapeutic interventions during this time that may be able to enhance Pao ₂/Fio₂ by 12 hours and improve subsequent outcomes.