I would add three items to the first aid kit - Hydrogen Peroxide and active charcoal - both for poisoning - the HPer to induce vomiting and the charcoal to absorb toxins. I'd also include a muzzle. If the dog is injured, the dog may attempt to bite while you're working on him. Another thing to consider is dog "booties" if you're in a urban environment and may have to go through rubble.