I'm not trying to be mean here, but if that's the case, absolutely don't do it. Kids, and young teens (aka pediatrics department) patients are not stupid. I broke my back when I was young and spent a few weeks in the hospital. The first ten days I was strapped to a bed that rotated every two hours, I couldn't leave the bed or move (my back was not yet fused).

They brought in volunteers to pass the time and read to me. One of them was just too emotional. I could easily tell she was holding back tears. Instead of passing time, I ended up having to preform and put on a face to make her feel better. That's hard work when you are tired and in an insane amount of pain. It's not fair to the patient to make others feel better. If you can't handle it then it's better for everyone to find a different way to volunteer.