Merging.

perhaps close enough.

there seems to be a distinction in that ぎゃっ is often the kind of yelp you'd let out when being crushed or having your foot stepped on, whereas きゃっ is merely from being startled.

don't forget about きゃあ (1631770).  if there's not a total merge, then at a minimum, きゃっ should probably be merged into きゃあ.

Daijr, etc.

I see Daijirin has almost identical glosses for きゃっ and ぎゃっ. I think a merge is appropriate.

I came to this entry expecting to find that きゃっ meant "ouch", but instead it lists a more generic shriek or scream. So then I looked up "ouch", and I discovered that きゃっ does indeed mean "ouch", but that is listed under a separate entry for ぎゃあ; ギャー; ぎゃっ; ギャッ.  Seems like these two entries could be combined, perhaps :-)