My daughter's first stay was at 14 months of age. We did not stay for all three weeks of IVs. We stayed about 5 days and then they let us do the rest at home. I highly suggest using the first few days to show that you are competant and capable of doing it at home. Its soooo much easier for the little ones to do it from there.
If you have a backpack that came with the g-tube pump, bring it with you. You can stick the IV pump in there and make it easier to keep him running on the IV without penning him down for so much time.
At 18 months of age there is a limit to things to keep them entertained. Try and set a routine as best you can, bring lots of videos and crayons and other loved activities -- maybe music or something you rarely do like finger paint or play doh.
Our hospital has a very set plan and for all three admits its been much the same for us. First we plan the PICC line insertion. If they dont' offer, ask for some kind of sedation during the PICC. They give my daughter versed and it helps her to be calmer and forget the pain and the insertion. Once the PICC is in, life is good because they can draw blood off it and add the IV meds when its time.
You'll see a lot of different people. Always plan to be around the room most of the morning as the docs drop in on rounds between 6am and 11ish. You'll have Respiratory Therapy coming several times a day for PT. If its important to stay on schedule for you, dont wait for them, do it yourself.
PT will also come by once a day and do some activity or excercise with the kiddo.
You'll see all the CF team members during the day, it can get overwhelming for sure.
Bring yourself a cooler and some drinks, snacks and shelf stable meal things (yogurt, banannas, microwavable easy macs, bread and peanut butter, etc. are things I keep) because if you have to rely on the cafeteria to eat all your meals you will be broke. The hospital takes care of the kiddos meals, but ours won't deliver parent meals.
Make use of child life and volunteers to give you a few minute break.
I bring my laptop and pillow so I will be comfortable and able to connect to the internet. Our hospital has private rooms and wifi, so we are very lucky. Find out about yours.
(((()HUGS)))) Hospitalizations are soooo hard, but they definitely get easier over time. At age 3.5 my daughter is much easier to entertain, so know that that part will get better.
If you have any questions, feel free to PM me or ask me here.