Something that needs to be noted, is that mouth to snout on puppies and kittens should be done very carefully, with their lung capacity in mind. You can cause a rupture by breathing for a human when you have a baby animal in your hand.
I have used this successfully several times, only once on a puppy, but on several kittens including a one ounce premature scrap, that took 15 minutes to revive. Cardiac compressions on her were a challenge, given that she would about the size of half my little finger. But she's a good size, very lively four year old cat, today.
*********************** Sea hags have feelings too. Honest!!!