Cardiopulmonary resuscitation (or CPR) was the Terran term for the manual stimulation of an individual's heart and lungs for the purpose of resuscitation.
In 2268, an amnesiac Captain James T. Kirk performed CPR and mouth-to-mouth resuscitation on a boy who had become entangled in fishnets and sank to the bottom of a river on the planet Amerind. (TOS: "The Paradise Syndrome")
Despite the many technological advances, CPR was used during the 23rd century if so required. Dr. Leonard McCoy attempted CPR on Chancellor Gorkon after technological methods failed. Although McCoy's CPR (along with what was possibly the "precordial thump" technique) revived Gorkon, he died moments later. (Star Trek VI: The Undiscovered Country)
In the 24th century, CPR was used solely in field medicine when other stimulant technologies were unavailable. It was typically used in conjunction with cordrazine, which was included in all field first aid kits. (VOY: "Coda")
CPR proved ineffective for patients who had lost a significant amount of blood. In 2374, Kathryn Janeway attempted CPR on a dying crewmember, but was discouraged by The Doctor for that reason. (VOY: "Scientific Method")
Ensign D'Vana Tendi performed CPR on Ensign Brad Boimler in 2381 when he nearly drowned in Cetacean Ops on the USS Cerritos, and was successful in resuscitating him. (LD: "First First Contact")