First, find out if your dog is seriously injured or ill. If so, then you need to stabilize him. If he has been hit by a car, stop traffic to get him out of the way. Maybe you will need help with this. Flag down the cars on the other side of the street and ask them to block the road while you move your dog. Find a gauze or a strip of cloth to tie around his muzzle, because he may act aggressively toward you due to his pain and fear. Take special care when you move him, because he might have a neck injury. To support his weight, find a large, sturdy piece of wood or a sheet. With help, carefully maneuver him onto the board or taut sheet. Be gentle and do not jostle him.
Access your dogs condition once he is out of danger. Is he conscious, bleeding or in pain? If he is bleeding, to stem the blood flow, apply direct pressure to the wound. If he is having difficulty breathing, check his mouth to remove any foreign objects, and then perform mouth-to-mouth resuscitation. Perform CPR if you cannot get a pulse. To find out about the proper way to administer CPR and mouth-to mouth resuscitation, talk to your vet. He or she may refer you to a canine first aid training class.
Gently load your dog into your car, once he has been stabilized. To let the staff members know that you are on your way, call your vet or the closest emergency clinic. Let them know as much information about what has happened to your dog as possible, and when you will be arriving. To be sure that there is no problem with payment, bring a checkbook or a major credit card with you. To monitor your dogs condition while you are driving, bring a friend or a neighbor with you.