Sonia,
At Great Ormond Street (where I used to work) and in Portsmouth neonatal unit there are 572s. The reason being that you can set the occlusion pressure accurately to the nearest mmHg. The idea being that you can set tight alarm limits to get a fast alarm should the infusion tissue. The 572 is currently the only IV pump to have such a facility but I believe the AsenaVP will be out soon (and has been going to be "out soon" for a long time!!)
BUT....
As the pressure tends to drop when an infusion tissues before it goes up even a tight alarm limit is no replacement for frequent observation of the infusion site.
Robert