Donor Ventilation Parameters as Predictors for Length of Mechanical Ventilation after Lung Transplantation: Results of a Prospective Multicenter Study

Abstract

<h3>Purpose</h3> The evaluation of donor lungs heavily depends on the subjective judgment of the retrieval surgeon. As a consequence, acceptance rates vary significantly among transplant centers. We aimed to determine donor ventilation parameters in a prospective study and test if they could be used as objective quality criteria during organ retrieval. <h3>Methods</h3> A prospective evaluation of lung donors was performed in three transplant centers. Ventilation parameters were collected at the time of retrieval using a standardized ventilation protocol. Recipient length of mechanical ventilation (LMV) was defined as the primary endpoint and collected data was used to build linear models predicting LMV. <h3>Results</h3> In total 166 donors were included in this study. Median LMV after transplantation was 32 hours (IQR:20-63). Peak inspiratory pressure (P_IP) and dynamic compliance (C_dyn) at the time of retrieval but not P/F ratio correlated with recipient LMV in Spearman correlations (r=0.280, p=0.002; r=-0.245, p=0.003 and r=0.064, p=0.432 respectively). Linear models were built to further evaluate the impact of donor ventilation parameters on LMV (table 1). The first model was based on donor P/F ratio, donor age, donor intubation time, donor smoking history, donor pCO2, aspiration, chest trauma and pathologic chest X-ray. This model performed poorly (multiple R-squared=0.063). In a second model, donor ventilation parameters were included and C_dyn was identified as the strongest predictor for LMV. The third model was extended by recipient factors, which significantly improved the robustness of the model (multiple R-squared=0.293). <h3>Conclusion</h3> In this prospective evaluation of donor lung parameters, currently used donor quality criteria poorly predicted recipient LMV. Our data suggest that C_dyn is a strong donor-bound parameter to predict short-term graft performance, however, recipient factors are similarly relevant.