I usually write a random number for respirations when taking vital signs
Why not write the actual number?
I think if it is shocking they will pay more attention to them.
You should just write the correct resp. number! It can cause a lot of issues lying about medical stuff like that.
What's the harm in me writing some random numbers sometimes? If they can't figure out my methods then they aren't good enough.
You could hurt someone or get them killed if you lie about something so critical. You have a duty to make sure the number is accurate you could be sued if they die.