The aim of this investigation is to compare two different anti-coagulation strategies in clinical lung transplantation where lung implantations are all routinely done on veno-arterial (VA) extracorporeal membrane oxygenation (ECMO) support at the investigators' institution. No heparinization (Zero-Hep) will be compared to standard low-dose heparinization (Standard). Traditionally, the Vienna group has used a standard low-dose heparin protocol with unfractionated heparin (UFH) administered as a bolus upon ECMO cannulation. With heparin-coated tubing and intraoperative ECMO flow never falling below 1 L/min, the likelihood of thromboembolic events is believed to be negligible. To date, the investigators have not experienced any thromboembolic events during intra-operative ECMO use. On the other hand, the use of UFH entails an increased risk for bleeding, so it follows that avoidance of additional heparin may be beneficial. Generally, risks and benefits of heparinization during these short procedures have not yet been thoroughly analyzed. This study will investigate the feasibility of running heparin free VA-ECMO support during clinical lung transplantation and its effect on clinical outcomes and inflammatory response comparing 40 patients receiving a standard dose of heparin versus 40 patients receiving placebo in a randomized, double-blind study design.

Inclusion Criteria:

• Double lung transplantation
• Age of 18 or older at the time of the procedure

Exclusion Criteria:

• Single lung transplantation
• Re-transplantation
• Previous major thoracic surgery (excluding pleural drainage, video-assisted thoracoscopic - (VATS) biopsy)
• ECMO bridge to transplantation
• Coronavirus(COVID) - acute respiratory distress syndrome (ARDS) as transplant indication
• Pre-operative anti-coagulation/anti-platelet treatment
• Paediatric transplantation
• Multi-organ transplantation
• Active pregnancy or breastfeeding.