Lung transplant: balance between sparing lungs and administering fluid.

Just curious what the concensus is out there with thoracic transplant nurses. I am relatively new to the thoracic specialty (8 mos thoracic, but RN for 5 years with Neuro ICU background prior) and I haven't figured out the balance between tolerating a low MAP and CI versus giving fluid to bolster the index of a lung transplant pt. I know giving fluid potentially sacrifices the health of the new lungs even when it improves numbers.

I have a pt who was transplanted a week ago (relatively healthy young pt in 30's) and got a large pair of lungs...so large that they opened the pt back up for several days to allow the inflammatory process to ease before closing the chest again (after repeat periods of SVT 170's and CI <1.2). So the pt is closed but still on NO and 80% O2 and Maps are now low 50's, CI 1.6-1.9, SVO2 low 60's, UOP amazingly 30-40/hr, HR low 100's. pt sedated but follows commands c stimulation. Pt numbers just hang here and occasionally drops lower. CVP is about 7. I know that the ideal cvp is 4-7 for lung transplants so I hesitate to give fluid, but it's unnerving to see an index bounce from 1.6-1.9 (postop this pt was very fluid dependant for index) with a young, previously healthy heart. What are your thoughts? When should I start pushing for fluids, especially in light of the fact that the pt was fluid dependant for CI postop? I'm at a teaching hospital on noc shift so the residents aren't exactly pros at this and I have to be proactive to get things done. Any insight would be greatly appreciated. thanks.