Go early and get all the pt's labs, imaging reports, carry washington manual with you, get a palm/pocket pc with PDR and MD consult, or whatever you can get-one for meds, one for diagnosis.
Update the labs/meds that you have o your pts as they change. When i did my ICU, i used to make a copy of my progress note. And the progress note each day would have everything!!-Current meds, Vital signs with averages and maximum, vent settings, I/O for 24hrs, etc. Watch for any small changes like pt's course over night.
Order CXR, CBC, BMP for all ICU vent pts. AbG's when necessary and know what it means to have certain tidal volume, PEEP etc.
Also, you should ALWAYS BE THE FIRST PERSON to know the results of any lab/imaging results that was done. If it is a CXR, make sure you see the xray and compare with previous.
Sometimes, if you are not attentive and careful, esp. during rounds, other people-esp. nurses will know something about your pt, like pt. desaturated temporarily overnight and an ABG was ordered-and they will give the info. to the attending and you will look bad. So read everybody's progress notes, including nursing and nutrition.
Now as for codes, intern always has a backup resident. So your job mainly is supportive, and trying to help out-you are not running the code ever. The resident is ultimately responsible, so not to worry. But the difficulty is handling the rounds and other times at night. Now it gets easier after the first couple of wks.
NOW THE INFO ABOVE APPLIES FOR MEDICINE ICU, but surgical intern pretty much is incharge of post-op, re-op etc, so add on to this dressing changes, drainage, trauma cases. Good luck.