Long-Term Weaning of Mechanical Ventilation After Lung Transplantation: Patient Characteristics and Impact on Survival

Abstract

<h3>Purpose</h3> Following lung transplantation (LTx), some recipients may require a prolonged postoperative course including long-term weaning of mechanical ventilation, raising concerns regarding transplant benefit. The aim of this study was to characterize this subgroup of patients, identify risk factors of prolonged mechanical ventilation (PMV), and determine impact on survival. <h3>Methods</h3> We retrospectively reviewed all adult LTx procedures performed at our center between January 2008 and January 2019 (n=1138). Logistic regression analysis of baseline characteristics and peri-operative variables was utilized to identify risk factors for PMV. The subgroup with PMV > 60 days was then compared to a random sample of patients of equal size with short MV (< 48 hr). <h3>Results</h3> Fifty-eight patients (5%) underwent PMV > 60 days (median 99.5, IQR 71-152 days). Independent risk factors for PMV > 60 days were bridging on MV, double (versus single) LTx, concomitant cardiac procedure, re-exploration for bleeding, and primary graft dysfunction higher grades. At time of LTx listing, the group with PMV > 60 days had higher lung allocation score (72 [44-89] vs 40 [35-48], p < .01), greater chest wall soft tissue to pectoralis muscle thickness ratio (3 ± 1 vs 2 ± 1, p = .02), lower 6-minute walk test distance (873 [680-1058] vs 1003 [821-1183], p = .03), increased bridging on MV (72% vs 53%, p = .03) or ECMO (29% vs 0%, p < .01), compared to patients with short MV (< 48 hr). The group with PMV > 60 days underwent more double LTx (93% vs 48%, p < .01), cardiopulmonary bypass utilization (93% vs 45%, p < .01), concomitant cardiac procedures (29% vs 5%, p < .01), re-exploration for bleeding (36% vs 3%, p < .01), delayed chest closure (52% vs 2%, p < .01), post-LTx ECMO (24% vs 0%, p < .01), and had higher primary graft dysfunction grade 3 (48% vs 2%, p < .01). Additionally, patients with PMV > 60 days had higher hospital mortality (15% vs 3%, p = 0.02) and lower 1-year survival (59% vs 86%, p < .01); however, there was no difference in 3- or 5-year survival. <h3>Conclusion</h3> LTx recipients who undergo long-term weaning of MV have unique baseline characteristics prior to listing that influence the likelihood of a prolonged perioperative course and worse short-, but not long-, term survival. Understanding the specific predictors of PMV, and which are potentially modifiable, would contribute to optimal recipient selection.