We have taken international trips over seas. My biggest concern was the long ride on the airplane, and medical care. We took quiet toys that the kids liked, as well as presents that she could open once we are on the air plain. If you want to know more details of what we found helpful, I’ll write more on this issue later. Your concern is the first aid kit for the 18mo. What I always carry in my car, in my diaper bag and on trip are some what similar. Bandage, small scissors, tweezers (make sure these item are in the suite case, and not on your carry on) bottle of saline or cleaning solution, iodine for cut and open wounds, clean towel, Zip Lock bags and disposable ice pack (the one you squeeze and shake to activate it) for mostly bumps. You may want to carry children’s Tylenol, since over the counter medications in Italy are much stronger than the ones sold in US. Bon voyage!!