Evaluation of the oxygenation ratio as long-term prognostic marker after lung transplantation.
OBJECTIVE
We hypothesized that the arterial blood gas oxygen tension/fraction of inspired oxygen ratio (PaO2/FiO2) would prove to be useful as a mortality marker after lung transplantation (LT). The aims of this study were to define the prevalence of various ranges of PaO2/FiO2 during the first 24 hours after LT and to evaluate which measurement using the PaO2/FiO2 best correlates with mortality.


METHODS
A retrospective study was performed that included all patients who underwent LT from 1997 to 2005. We collected PaO2/FiO2 ratios at 0, 12, and 24 hours after admission to the intensive care unit (ICU). We classified the 132 patients in 5 groups, based on PaO2/FiO2 (Group 1, PaO2/FiO2 <100; Group 2, PaO2/FiO2 100-199; Group 3, PaO2/FiO2 200-299; Group 4, PaO2/FiO2 300-399; Group 5, PaO2/FiO2 >or=400). The correlation between PaO2/FiO2 and mortality was studied using Cox regression.


RESULTS
Cox regression analysis showed that PaO2/FiO2 at 0 and 12 hours after admission to the ICU were not useful mortality markers. However, the PaO2/FiO2 at 24 hours after admission to the ICU was a useful long-term prognostic marker. PaO2/FiO2 >100 (groups 2, 3, 4, and 5) at 24 hours was significantly associated with less mortality when a lower PaO2/FiO2 was the reference (hazard Ratio: 0.08, 0.02, 0.05, and 0.02, respectively). On multivariate analysis PaO2/FiO2 >or=100 (groups 2, 3, 4, and 5) at 24 hours was significantly associated with less mortality when a lower PaO2/FiO2 was the reference (hazard ratio: 0.07, 0.003, 0.01, and 0.005, respectively).


CONCLUSIONS
A value of PaO2/FiO2 >100 mm Hg 24 hours after admission to the ICU is associated with a lower mortality.
González-Castro
A
A
Service of Intensive Care, Lung Transplant Unit, Hospital Universitario Marques de Valdecilla, Santander, Spain.
Llorca
J
J
Burón
J
J
Suberviola
B
B
Vallejo
A
A
Miñambres
E
E
D000328:Adult; D000368:Aged; D001784:Blood Gas Analysis; D005260:Female; D006801:Humans; D007362:Intensive Care Units; D016040:Lung Transplantation / Q000401:mortality / Q000502:physiology*; D008297:Male; D008875:Middle Aged; D010100:Oxygen / Q000097:blood*; D010101:Oxygen Consumption; D011379:Prognosis; D012189:Retrospective Studies; D016019:Survival Analysis; D017741:Survivors; D014019:Tissue Donors / Q000706:statistics & numerical data; D016896:Treatment Outcome
D010100:Oxygen