CPR

CPR, or Cardio-Pulmonary Resuscitation was a medical technique.

Martha Jones performed CPR to revive the Tenth Doctor from hypervolemic shock when the Plasmavore drank his blood. (TV: Smith and Jones)

Amy Pond used CPR to revive Rory Williams from near drowning, the effects of which he began to suffer after she released him from the medical care of the Siren. (TV: The Curse of the Black Spot)

Behind the scenes
A provider of CPR used chest compression and rescue breathing to continue blood flow, which provided oxygen to body tissues even if the heart and lungs had stopped. This allowed time for advanced medical treatment.

In the real world, this is a last chance technique. It is not restorative. Further medical attention is required and even then it is frequently unsuccessful.