Cautery could be useful in a bleeding situation if you knew what you were doing. I would think only small vessels could be done in a survival situation but would be difficult to see/cauterize. I have seen it used in the case of an open wound that wouldn't heal. It's pretty crude-putting red hot metal on an open wound. It did work when nothing else helped on a very humid island in the summer. Formed a scab very quickly. Deep wounds would not respond and might be made worse. VK