R. -
Our daughter had to be put under when she was 7 months old so they could put tubes in her ears. For us, they gave her just enough to but her under and brought her out as soon as it was done. It wore off in less than 15 minutes and the nurses that we left her with stayed with her until it was worn off and we could go back and see her.
They gave her some juice and recommended that we not feed her until we got home, and they gave her a strong dose of tylenol before we left.
I know it is scary to think about them putting such a little one under, but at least with our doctors they were very cautious and gave the smallest dose that would do the job and kept her under for the shortest amount of time possible.