Using an actor-network theory approach, this paper analyses two technologies used in resuscitation medicine to try to improve outcomes from cardiopulmonary resuscitation, which remain an ongoing disappointment to resuscitation practitioners. The technologies are mechanical chest compression, and the use of automatic external defibrillators in hospital. In both cases, the actor network that performs resuscitation is being rebalanced away from humans and in favour of machines. Despite these efforts, outcomes from resuscitation continue to be worse than resuscitation medicine would like. This paper analyzes why there has been such persistence (in one of the cases for over 40 years) with apparently 'failed' technologies, concluding that it is a way of ensuring medical control over the process.