Oxygenated Hemoglobin Predicts Outcome in Patients with Chronic Lung Allograft Dysfunction

Background: Long-term outcome of lung transplantation (LTx) recipients is limited by chronic lung allograft dysfunction (CLAD). In this setting of new onset respiratory failure, the amount of oxygenated hemoglobin (OxyHem; hemoglobin (Hb) concentration x fractional oxygen saturation) may provide valuable information. Objective: We hypothesized that OxyHem predicts survival of LTx recipients at the onset of CLAD. Methods: Data from 292 LTx recipients with CLAD were analyzed. After excluding patients with missing data or supplemental oxygen, the final population comprised 218 patients. The relationship between survival upon CLAD and OxyHem was analyzed by Cox regression analyses and ROC curves. Results: Among the 218 patients (102 males, 116 females), 128 (58.7%) died, median survival time after CLAD onset being 1,156 days. Survival was significantly associated with type of transplantation, time to CLAD, CLAD stage at onset, and OxyHem, which was superior to Hb or oxygen saturation. The risk for death after CLAD increased by 14% per reduction of OxyHem by 1 g/dL, and values below 11 g/dL corresponded to an 80% increase in mortality risk. Conclusion: Thus, OxyHem was identified as an independent predictor of mortality after CLAD onset. Whether it is useful in supporting therapeutic decisions and potentially home monitoring in the surveillance of lung transplant recipients has to be studied further.