During a wasted youth I poured over hundreds of The Hardy Boys Casefiles, where they'd receive and recover from a traumatic brain injury 3-5 nights a week (getting "knocked out").

Thanks to your comment I now know the other nights, where they were not rendered unconscious by blunt trauma, but rather through a rag of chloroform, they were probably inhaling phosgene too.

Those boys were sure putting their futures at risk!