This article reviews the physiology of cardiopulmonary resuscitation (CPR), monitoring and new devices for generating blood flow during CPR. Two controversial mechanisms of blood flow during chest compressions are described: the thoracic pump mechanism and cardiac pump mechanism. Also, new physiological aspects of blood flow, physiology of ventilation and gas transport during CPR are overviewed. A variety of alternative techniques and devices are now explored in order to improve perfusion pressures and/or blood flow during CPR, including active compression decompression CPR, inspiratory impedance threshold valve, phased chest and abdominal compression-decompression CPR and others. Initial methods of cardiopulmonary resuscitation monitoring are direct observations of pulse and respiration. Electrocardiogram remains the most essential tool for diagnosis and monitoring of cardiac arrest. Monitoring of diastolic blood pressure, myocardial perfusion pressure and end-tidal CO2 are also useful. Other types of monitoring during cardiac arrests can provide information about effectiveness of CPR.