• Cardiac arrest
• cardiopulmonary resuscitation
• resusitation
• sudden cardiac death
• sudden death
• ventilation

As we approach the 50th anniversary of modern cardiopulmonary resuscitation (CPR), there has been a renewed interest in the practical details of CPR, including training methods, the quality of CPR delivery and the very composition of CPR itself—that is, the ratio of chest compressions and ventilations given in a period of time. This latter topic has been the focus of intensive study and debate for the past decade. For example, increasing data have suggested that hyperventilation during CPR is both common and probably deleterious to patient survival. In addition, it has been recognised that most cardiac arrest victims do not receive bystander CPR, in part due to reluctance by the public to engage in mouth-to-mouth (MTM) respirations. Ramaraj and Ewy1 presented the case for removing ventilations altogether from the composition of CPR provided by the lay public (so-called ‘continuous chest compression (CCC)-CPR’ or, in current American Heart Association parlance, ‘hands-only CPR’).

The history of CPR has been a complex and serendipitous one. During the 1950s in Baltimore, Maryland, USA, Peter Safar demonstrated the importance of MTM ventilation as a key component of resuscitation in dramatic fashion. Safar performed experiments in which he pharmacologically paralysed medical students and showed that MTM ventilations served as an effective form of respiration.2 Within the same few years, Kouwenhoven and colleagues unintentionally discovered the significance of chest compressions. At the time, Kouwenhoven was studying defibrillation in a canine model of ventricular fibrillation (VF). He noticed that when he pressed down on the chest of the dogs with the paddles to defibrillate, the arterial blood pressure would increase. Along with his colleagues, they soon realised that …