First Aid is a service that some furry conventions provide for their members. Many conventions offer qualified people to perform first aid should the convention guests need it. First aid furs are generally on duty in shifts, providing 24 hour coverage.
At most conventions, the first aid staff are available to provide first aid (contact ConOps) but also carry radios and will respond to a reported medical issue to offer their assistance to a competent adult -- which may of course be refused. In the event of a medical emergency (a threat to someone's life), First Aid staff will provide basic lifesaving care within their skill level and equipment until the paramedics arrive. This has happened at a number of conventions including CaliFur.
 Liability concerns
Some states have a legal concept on the books known as "expectation of care". This means that if a convention offers "first aid services", a person who becomes injured and fails to (or is unable to) receive any medical assistance from a convention may be entitled to file a claim against the convention in civil court. While most liability insurance policies have "riders" available to offset this risk, it is expensive, and usually out of the budget of a furry convention. As such, a convention running in a state which has "expectation of care" is unable to provide first aid services.
Conventions in states which do not provide first aid services because of these legal issues include: