The purpose of first aid is to minimize the damage done by disease or injury and prevent infection, so that healing can proceed as rapidly as possible. Sometimes first aid is all you need, other times it is a temporary measure until further help arrives.
First aid can remarkably affect the outcome.
Once principles are understood, common sense must be applied. Remember, if you are in a panic, you will not be able to help anyone, so step back from the situation and gather your wits before you tackle the problem. You may not be the only animal who is excited. The injured horse will also be confused and excited which makes him dangerous. The Rules are as important as the first aid.