Leave details with trusted friends and family members (plural), down to how you're getting from the airport to where you're staying, along with names, telephone numbers of where you're staying and confirmation numbers of your flights. And if you have extra medical insurance or evacuation insurance, note that too, along with your policy number and the telephone number. Include your emergency contacts and keep that information on you.
If this seems like too much information to share, consider this: If you are unconscious or sedated, someone will need to act for you, which is distinctly different from acting like you. You don't want that. You want someone who is clear-headed and will, for example, remember to cancel your flight because you're not going anywhere, at least, not then.
I didn't do any of that prep work on one trip in the spring, and it cost me. Literally and figuratively. When I could eat again, my first meal was the return airline ticket I hadn't canceled. Like most airline food, it was highly unpalatable.
Solution: These plans aren't state secrets you're sharing. Give them up.
Recovery was slow, but what really hurt was my pride, in this case and every other. I know better, and I let things slide anyway.
Learn from my mistakes. Share your own so others can learn too. We are, after all, students of the world, which is why we travel. I'll be working to make the honor roll in 2020.
(Have a travel dilemma? Write to email@example.com. We regret we cannot answer every inquiry.)