Muzzy field Test #1!

[Rustywreck]

Just goes to show that it doesn't matter what broadhead you use, an arrow that doesn't hit where you wanted to (for many reasons) can produce either a non-lethal hit or a dried up blood trail.
My sympathies to you guys and everyone else who has (or will) hit a deer and not find it. It happened to me once and felt crummy for days.
The only advice I can give you is don't beat yourself up for it too much.
FYI, there is an area above the spine and below the top of the back that may not be immediately fatal.
This summer I saw two people who swore they made good hits on deer, maybe just a little high. One of them was found the next day the other wasn't found. The deer that was found was hit in this area. I can't tell you how far that deer went before expiring but it was the longest blood trial I ever followed.
I have learned to "stick it in the pit." I say that to myself everytime I draw on a deer so I focus on aiming at the arm pit. If the deer ducks the arrow, it'll hit square in the lungs. If it doesn't duck, it hits the heart.
That is one of the things I don't like about 3-D archery: The targets train you to aim at the center of the chest. If you aim at the same spot on a real deer and ducks even as little as 4", you could end up with a bad hit and a deer you never see again.
Of course, that's just my opinion.