A couple of years ago I took a mini course on pet emergencies. One of components was choking. If you believe your cat is in serious trouble, ie choking on something, you will have to try to get it out. And yes you will get scratched and/or bitten. Anyway, heres what they taught us. Open the cats mouth by holding the cat's head so that the palm of your hand is over the cats head, with your thumb and index finger behind the canine teeth. (Try doing this a few time before you have any emergency). Tilt the cat's nose upwards. Using your other hand open the cats mouth by placing finger on the lower teeth, pressing the jaw down. Look in mouth and remove object. EXCEPT - do not pull on a piece of string wrapped around a cat's tongue. Get her to vet immediately. If you can't see or remove the object or if your cat is struggling too much to let you see inside, pick the cat up by its hind legs, turn it upside down and shake. Slap it on the back while shaking it. This might help dislodge the object.
If your cat has something thats preventing it from breathing, it will lose consciousness. Continue to try and disloldge the object. Do not be afraid of getting your finger in its throat and trying to get hold of the object. Get your cat to a vet as fast as possible. Do mouth to nose resusitation if cat not breathing. Hope this helps.