If you need something what is most simmilar to SIPPV on Babylog than chose PRVC together with volume guarantie. If something simmilar to PSV than you go for PRVS= VS. Anyway you should have some representative in your country from Getinge. Get in contact with him/her. I know manual is very unfriendly written. Yes, NAVA is also of choice, but if you are without any lecture how to do that , it might be very difficult. Hope this help
Regards Tom