Could it also be something called laryngospasm? It feels like it can kill a person (but moar likely the spasm will stop once a person falls unconscious). This can be caused by fumes or ANY (normally benign) irritant as well as from ingesting pure, undiluted essential oils (eucalypus, mint....) Our mother (R.A.) got this after accidently/carelessly swallowing some undiluted eucalyptus oil.

There was a PLB breathing tek that helped her overcome a laryngospasm, however it was pure terror...as far as she told we, she was able to exhale but unable to inhale, so when that happened, she used the remaining exhale using the PLB breathing (slowly exhaling with pressure through pursed lips)......