Asfixiante is a closed fisted blow to the throat. The blow is rarely used and is reserved for use in a real life case of self defense. Asfixiante is not really used in the Capoeira game due to the risk of the blow. The punch is rarely used and is reserved for use in a true case of self-defense. The larynx and trachea are some of the soft tissues that can be easily damaged or destroyed by impact. For this reason, deliberate throat strikes are not allowed in the UFC under the Unified MMA Rulebook. This makes it very difficult to determine how effective a throat slap is in the "real world". It is by no means an easy landing strike. As already mentioned, the chin and arms do a good job defending the area. If you accidentally hit your chin, you can break your arm. Speculation aside, it's easy to say that if you've used this punch successfully, it's possible to inflict critical damage on someone.
Asfixiante is a punch to the throat. It is one of the few blows with a clenched fist, and it may not be surprising that it is aimed at one of the softer parts of a person's body. Although the throat is partially protected by the chin and shoulder, hitting this area would cause a lot of injury. In the short term, breathing would be difficult, and in the long term, the opponent could die of suffocation.