The past tense of give mouth-to-mouth resuscitation is gave mouth-to-mouth resuscitation.
The third-person singular simple present indicative form of give mouth-to-mouth resuscitation is gives mouth-to-mouth resuscitation.
The present participle of give mouth-to-mouth resuscitation is giving mouth-to-mouth resuscitation.
The past participle of give mouth-to-mouth resuscitation is given mouth-to-mouth resuscitation.