System Set-up for manual method
EVLP with STEEN Solution™ is a method to assess lung viability of donated lungs. EVLP aims to expand the potential donor pool, by providing a near physiologic environment ultimately leading to decreased inflammation and rejection.
In order to evaluate an organ in an ex vivo system the STEEN Solution™ must be circulated through the organ via an extracorporeal perfusion circuit that allows continuous flow of nutrients and gas at a rate set by the clinician.
The circuit (see figure 1) allows fine control of organ temperature, left atrial pressure, pulmonary arterial pressure, venous PaO2and PaCO2, which are targeted in a protocolised manner.
A heat exchanger is connected to the “venous” afferent side of the circuit to allow the perfusate to assume the temperature and partial gas pressures of normal venous blood. A leucocyte filter is connected to prevent recirculation into the circuit and the lung. A membrane de-oxygenator is employed with both pre- and post- “membrane exchanger” gases being continuously monitored; membrane gas flow varies according to phase of evaluation and technique employed. A standard ventilator is connected via an endotracheal tube secured in the trachea. The lungs are placed in the XVIVO Organ Chamber™, a dome devised to maintain humidity.
The STEEN Solution™ is a buffered extracellular solution that includes human albumin to provide an optimal colloid osmotic pressure and dextran 40 to coat and protect the endothelium from excessive leucocyte interaction.
STEEN Solution™ is designed to facilitate prolonged evaluation and promote stability of isolated lungs ex vivo.
Hardware requirements for an EVLP procedure are generally off-the-shelf standard cardiac bypass equipment and include the following items:
- Centrifugal Pump and flow sensor
- Heater-cooler unit
- Vital signs monitor
- Gas analyser (either online or by solution sampling)
- Cylinder with O2 100% and Cylinder of CO2 7% – N 93% (Lund method)
- Cylinder containing O2 6%, CO2 8% and N2 86% (Toronto method)
Disposables needed for manual method
Disposables needed for an EVLP procedure using the manual method include:
- XVIVO Organ Chamber™
- XVIVO Lung Cannula Set™ (Arterial and Venous cannulae)
- Heater exchanger
- Oxygenator membrane
- Centrifugal pump head
- Leukocyte filter