The metra perfusion algorithm is designed to accommodate negative IVC pressures, repeated collapses should not impact the quality of perfusion.
To minimise negative IVC perfusion pressures users should ensure that the liver is orientated in the correct position. The IVC cannula should exit towards the bile collection area before bending clockwise to meet with the IVC connector
Users should be observant of IVC pressures in the first 15 minutes of perfusion (it is normal to experience some negative IVC collapses during this period). Frequent / constant negative pressure should be investigated.
Liver outflow might be improve by rotating the liver slightly or by repositioning the IVC cannula. The tip of the cannula should be adjacent to the hepatic veins.