No, in the rules there is no such thing as CPR. There is a state of dying that can last at most 30 seconds.
I said using a Healer's Kit or the Healer Feat is the D&D
equivalent of CPR. If you don't want to see it that way, that's fine; but it doesn't change the fact.
Even historically, mouth to mouth resuscitation was known as early as 850BC (Elisha in the Bible - Book of Kings). Paracelsus described a form using bellows in the 1500's - that's late medieval age/early renaissance, consistent with most D&D. From the same time periods there's also records of compression-like techniques used on individuals - especially drowning victims.
Why would you think a Heroic D&D Healer wouldn't know these things? The Healer Feat is vague on this on purpose. D&D is used for too many genres and representations of far too wide of a range of pseudo-historical periods to do so, shouldn't require players to know the history of medicine, and the PHB shouldn't be
Gray's Anatomy.
And not to mention, I think you over-value the impact of CPR. CPR is effective in our modern day because of modern emergency room care and things like defibrillators. CPR is mostly just a stop-gap until some other form of care can begin. By itself, CPR has only about a 10% to 15% success rate of reviving people.
That would be an 18, 19, or 20 on a D20 roll...
Pretty long odds, and definitely not consistent with a non-magical form of
Revivify.
And again, that would be the realm of a character with the Healing Feat - someone the Feat describes as an "able physician" - something that a Warlord, by concept, simply
is not.
Now if a Warlord wants to take the Healer Feat, that's a different story.
15% of people who fall into this state stand up again of their own accord if left alone. The remaining 85% die. If you intervene, there is a procedure you can do in 6 seconds that will stop them from dying, but won't help them regain consciousness.
That's incorrect. A Healer using a Healing Kit restores a character to 1 HP and consciousness - by the rules.
This is clearly different from someone who has been dead for less than 4 minutes and can be revived via CPR which may last a minute or more.
While 10% to 15% of people may revive with CPR, I'm betting the percentage of those that revive after a minute or more of CPR alone is extremely rare - like one in a million rare.
Reviving after a minute or more would almost always require defibrillation (the D&D equivalent being
Magic), or long-term life-support with potential revival after a significant period of time and medicinal stimulation.
Again, waaaaaay outside the concept of a Warlord - and not to mention way outside the concept of D&D itself.
While that's certainly one definition of death, it's clearly not the version that happens in D&D, for the reasons I outline above. Brain death takes minutes, not a maximum of 30s.
No, D&D doesn't clearly describe death at all - just the mechanical effects and when it happens. However, the real-life definition of death is consistent with D&D - with the only exception being time.
While I fully agree that the time aspect in D&D is inconsistent, it's hardly reinforcement for the argument that a Warlord should be able to revive a dead character.