(1) A person commits the offense of assault by strangulation or suffocation if the person knowingly and intentionally:
(a) Impedes the normal breathing or circulation of the blood of another person by applying pressure on the throat or neck of the other person; or
(b) Impedes the normal breathing of another person by covering the mouth and nose of the person.
(2) An offense is committed under this section regardless of whether a visible injury resulted.
(3) Except as provided in subsection (4) of this section, a violation of this section is a Class IIIA felony.
(4) A violation of this section is a Class IIA felony if:
(a) The person used or attempted to use a dangerous instrument while committing the offense;
(b) The person caused serious bodily injury to the other person while committing the offense; or
(c) The person has been previously convicted of a violation of this section.
(5) It is an affirmative defense that an act constituting strangulation or suffocation was the result of a legitimate medical procedure.