The EVLP process in short
- At the donor site the donor lungs are flushed thoroughly and preserved with PERFADEX® – the gold standard in lung preservation specifically formulated to preserve the function and integrity of the organ.
- The lungs are transported following clinically proven routine practice in a cooler from the procurement site.
- At the recipient site the donor lungs are cannulated, flushed thoroughly with PERFADEX® and connected to the XPS™ machine.
- After progressive warming according to a detailed protocol, the EVLP team is free to set preferred ventilation and perfusion strategies depending on the requirements of each donor lung.
- Integrated in-line perfusate gas monitors (PGM) enables for real-time trending of pH and pO2 during the entire EVLP procedure.
- The XPS™ also enables precise continuous monitoring of EVLP performance metrics, all pre-set by the EVLP team.
- The XPS™ is specifically designed to permit X-ray scanning during the normothermic EVLP procedure. If a mobile unit is not available, XPS may be transported within the hospital since it incorporates a long life battery. This permits for simultaneous X-ray without interrupting the EVLP process.
EVLP with STEEN Solution™ will help expand the pool of available organs by allowing assessment of marginal lungs under optimized conditions. Several mechanisms contribute to this:
- The warming and reperfusion period allows time for the lung to re-establish a near-physiological environment which reduces the subsequent risks of inflammation and rejection. The ex vivo perfusion is carefully controlled using a lung-protective strategy.
- The physiological problems caused by neurogenic pulmonary edema in the organ donor with respect to electrolytic balance, colloid-osmotic pressure and temperature may be reversed during this protective reperfusion period.
- Any remaining donor blood still in the lungs (containing coagulation factors, complement, activated white cells, inflammatory cytokines and non-physiological substances, including drugs used during donor management) is diluted and filtered away during the EVLP. This washing out benefit is not achieved with current hypothermic perfusion as the cold temperature induces vascular constriction within the lung, preventing complete flushing.
- It facilitates removal of clots in the pulmonary circulation through the use of transient retrograde perfusion at the beginning of the procedure.
- The ex vivo system provides an excellent environment for recruitment and re-expansion of atelectatic lung areas.
- It allows time to assess and clean/suction bronchial secretions.
- It allows for all ventilatory volumes and pressures to be transferred directly to the lungs without interference of the chest wall and diaphragm.
- The dextran in the perfusate solution facilitates perfusion of the pulmonary micro-vasculatureby reducing interaction of activated leukocytes and platelets with the vessel wall.