Critical Care documentation

Do you know if it states anywhere who must document what was done to bill out a critical care service? I have an intensivist who is insisting that he can use what the RN documented as long as he co-signs his/her note and documents his own time. I feel the physician must document himself what he did to stablize the patient, etc. but I cannot find it in writing anywhere, so he is giving me pushback on it. Any guidance would be appreciated.

re: Critical Care documentation

Critical care is a time based service so the doctor must document time spent. So if the doc documents "spent 60 minutes in critical care of patient" it technically meets the requirement but the patient must be critically ill and so the RN note cannot just say "Dr smith rounded on patient and wrote orders"- it must justify the patient's critical condition