I dont know if this is the technical name, but when we installed window guards, we were concerned about the same thing. We bought, what the installer called a “fire department approved” window guard. they are made for buildings with a fire escape and they easily open from inside to allow someone to get out in case c”v there is a reason to get out.
I dont know if you live in NYC, but if you do this may be helpful.
http://www.nyc.gov/html/fdny/pdf/fire_prevention/fire_escape_window_gates.pdf
If outside NYC, at least this will help you if you want to change what you have.