Most cats love to curl up in drawers and cupboards. I would think that if you turned off all the noise in the house and listened, you should hear it if it is conscious and trapped. As I'm sure we all know, cats are vocal when in trouble.
If he got outside and it's cold, keep checking the outside window sills. My outdoor cats sit there to watch me like tv.
If you still think he got out, put some catfood on your porch and see if he shows up. Their noses aren't as good as dogs, but if he gets hungry enough, he might find it.
Chin up, though, cats truly do seem to have 9 lives and can survive the most amazing things.