Search

Introduction Mechanical ventilation (MV) plays a crucial role during the early post-operative period of lung transplantation (LTx). An accurate setting of MV is important in order to prevent ventilation-induced lung injury, which may lead to Primary Graft Dysfunction (PDG), and to set a protective ventilation strategy whenever this complication occurs. Unfortunately, respiratory mechanics may be unpredictable: these patients receive lungs which may not perfectly match their chest walls, causing a patient-donor size-mismatch, is conventionally defined by the ratio between recipient and donor lungs predicted-Total Lung Capacity (r-pTLC and d-pTLC, respectively) and may modify the distribution of pressures inside the respiratory system between lung and chest wall. In order to improve our understanding of the LTx respiratory mechanics and to evaluate whether ventilation setting was dangerous for the transplanted lungs, we placed an Esophageal Balloon Catheter (EBC) and analysed the esophageal pressure (Pes) in the early post-operative period of patients receiving bilateral sequential single LTx (BSSLTx). Methods We observed the respiratory mechanics of patients receiving BSSLTx over 1-year period at Molinette Hospital (Ospedale Molinette, Citta della Salute e della Scienza, Turin, Italy). For each patient respiratory mechanics was evaluated at least two times in the post-transplant period: intraoperatively (T0), just before the chest closure, and post-operatively (T1), in ICU. Patients and donors data, recipient-donor size-matching and outcomes were compared with respiratory mechanics. Results Between November 2018 and October 2019, we included 22 patients receiving LTx. Among them, 9 were excluded: 6 were single LTx, 1 was a paediatric patient and 2 patients had incomplete data. Among the 13 patients included, 3 (23%) developed PGD: 5 patients were best matched (d/pTLC 0,9 – 1,1; 5/13, 38,4%), 6 were undersized (d/pTLC 1,1; 2/13, 15,3%) but no correlation was found between size-matching and incidence of high-grade PGD (PGD grade 2 or 3) (Fig.1). We found no statistically significant difference in transpulmonary pressure (PTP i, PTP e, PTP drive), transpulmonary compliance (CTP) or chest elastance (ECW) at T0 or T1 in patients who developed PGD compared to those without PGD. However, we noticed an early raise of PTP i in patients who were going to develop PGD (no PGD δ% t0-t1 PTP i – 14,6% vs PGD δ% t0-t1 PTP i + 14,0%; p=0,1402) (Fig. 2). Moreover, we found that this early raising in PTP i (δ% t0-t1 PTP i) was statistically related with the ICU-length-of-stay (ICU-LOS) (r2=0,57; p=0,050) (Fig. 3) Discussion The overall incidence of PGD in our centre was 23%, however no correlation with patient-donor size-matching. An early raise of transpulmonary pressure was observed among patients who developed PGD and it was statistically correlated with higher ICU-LOS.