Cats who are severely injured may act aggressively toward their pet parents, so it's important to protect yourself first from injury. Gently place a blanket or towel over the cat's head to prevent biting; then slowly lift the cat and place him/her in an open-topped carrier or box. Take care to support the cat's head and avoid twisting his/her neck in case s/he suffered spinal injury.
Once you feel confident and safe transporting your cat, immediately bring him/her to an emergency care facility. It's also a smart idea to ask someone - a friend or family member - to call the clinic, so the staff expects you and your cat.
Most emergencies require immediate veterinary care, but first aid methods may help you stabilize your pet for transport.
CPR may be necessary if you successfully remove the choking source, but your cat is still unconscious. First check to see if s/he is breathing. If not, place him/her on his/her side and perform artificial respiration by extending his/her head and neck, holding his/her mouth closed and blowing gently into his/her nostrils once every 3 seconds. If you don't feel a heartbeat, incorporate cardiac massage while administering artificial respiration - five (5) chest compressions for every respirration - until your cat resumes breathing on hjs/her own.
If you suspect your pet has ingested a toxic substance, please call your veterinarian or the ASPCA Animal Poison Control Center's 24-hour hotline at (888) 426-4435. Trained toxicologists will consider the age and health of your pet, what and how much s/he ate, and make a recommendation - such as whether to induce vomiting - based on the assessment.