Hi!
It's my 5 yr old who wears a pump:
I actually find the 'non flat bits' to be better site areas! She has quite skinny/muscular thighs and tummy so no, I wouldn't get her to lie down as that would 'stretch her out' even more if you get what I mean?! The best sites are when I can pinch up for insertion. We get 3 days out of her hips/bottom area and only 2 days out of her thighs. We've started putting her CGM, not her pump, in her arm and are getting excellent results here. This is advice I've got from American mums. We've never been advised to use the arm by our medical team here (nor have we been not advised to). I know that the Americans use the arm for the pump too. We weren't keen cos of the tubing but it might be worth looking into - ?
We changed from a cannula to a smaller stainless steel needle as what was happening was my daughter didn't have a big enough layer of fat on her so the tip of the cannula was hitting muscle and this was reacting to the foreign body and was closing over the tip of the cannula. We had countless kinked cannulas, occlusions & site failures until we changed sets.
Good luck!
Vikki
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