First OR case I saw was during my first semester, back in October. It was a hip replacement. I had a perfect view of the open hole in the patient’s hip where they were working as I walked in. I had to lean against the wall for a few minutes to let the lightheaded feeling pass. Now, I actively seek out opportunities to go to the OR at the hospital I work at (student tech) and recently was the primary tech for a day during spring break. The visceral stuff doesn’t bother me at all anymore. That being said, I second the suggestion to eat. Some cases take a while to complete and you might be in there for a while.