Respiratory System Compliance Predicts Outcome After Lung Transplantation-A Retrospective Single Center Study

Abstract

Background: Outcome prediction in patients undergoing lung transplantation (LUTX) for end-stage pulmonary disease can be challenging. We examined the prognostic value for mortality of respiratory system compliance (C_RS) and mechanical power of ventilation (MP) at end of surgery in patients undergoing LUTX for end-stage pulmonary disease. Methods: In this single-center retrospective study, we included 755 patients undergoing LUTX between 2014 and 2023. The primary endpoint of this study was 1-year mortality, with 30-day mortality serving as a secondary endpoint. We conducted both univariate and multivariate analyses and constructed Receiver Operating Characteristic curves. Results: Of 755 patients, 1.9% and 12.2% patients died within 30 days and 1 year after LUTX. Fifteen-point four percent of all patients required extracorporeal membrane oxygenation (ECMO) prolongation into the early postoperative period. C_RS, but not MP was higher in 1-year survivors compared to non-survivors [median 25.8 mL/cmH₂O (20.1, 32.1) and 22.5 mL/cmH₂O (15.2, 28.4); p < 0.001] and [median 10.0 J/min (7.8, 12.0) and 9.3 J/min (6.2, 13.1); p = 0.329]. Moreover, low C_RS < 25.1 mL/cmH₂O remained an independent factor for increased 1-year mortality after LUTX. Additionally, increased MP and C_RS were predictive for 30-day survival with an acceptable area under the curve of 0.758 (95% CI: 0.6-0.8; p < 0.001) and 0.735 (95% CI: 0.5-0.9; p = 0.003), and a sensitivity and specificity of 51% and 75.5% for MP and 50% and 85% for C_RS, respectively. Conclusions: Postoperative C_RS serves as a significant independent predictor for short and long-term outcome in patients undergoing LUTX with and without ECMO prolongation into the early postoperative period.

Keywords: lung transplantation; mechanical power; outcome; respiratory system compliance.

Figure 1

CONSORT Statement of patients undergoing LUTX with and without ECMO prolongation n this study, we included 755 patients who underwent orthotopic primary double LUTX. 118 patients required ECMO support in the postoperative period, and 637 did not require prolonged ECMO support into the postoperative phase. Five and 9 patients with and without ECMO support died within 30 days after LUTX. Moreover, 30 and 62 patients died within 1 year after transplantation with and without ECMO support, respectively.

Figure 2

Differences in C_RS and MP between 1-year survivors and non-survivors and in patients with and without postoperative ECMO support. This panel shows the significant difference in C_RS between 1-year survivors and non-survivors (A). C_RS is decreased in patients with ECMO prolongation compared to patients without ECMO support (B). MP did not differ statistically significantly between 1-year survivors compared to 1-year non-survivors (C). In contrast, patients without ECMO prolongation had a significantly increased MP compared to patients on ECMO support (D). Respiratory parameters for calculating MP2 and C_RS2 were collected during the final 15 min before the end of surgery, i.e., after chest closure.

Figure 3

The predictive power of C_RS and MP on 30-day and 1-year survival. C_RS significantly predicts 30-day survival for the total cohort and for patients with and without ECMO (A). C_RS significantly predicts 1-year survival for the total cohort and for patients with, but not without ECMO (B). MP predicts 30-day survival for the total cohort, but not for patients with or without prolonged ECMO support (C). MP did not predict 1-year survival for the total cohort or for patients with and without postoperative ECMO use (D).