We are at the airport in Costa Rica and my blood glucose has been running kinda high all morning. I corrected on the drive (2 1/2 hours), but we also stopped and got snacks. Waiting at the gate for the flight I see the double up arrows and realize I need an infusion set now.
I open my carryon, pull out my supply bag and guess what? No infusion set. I have everything on earth! But no infusion set. So, I quickly decide to go on Lantus. I bolus, give shots for my high BG and everything worked out ok. I still had my CGM connected, so I could monitor the results.
I didn't realize until a few years ago that your dose of Lantus is equal to your total basal rate. Worked pretty well.
So, you can always be prepared, but you also need to be prepared to be flexible!