Searching for factors contributing to substandard quality of cardiopulmonary resuscitation in out-of-hospital cardiac arrest

Prehospital, unexpected cardiac arrest is a major cause of death within emergency medicine, with more than a million cases reported every year in the western world. It requires urgent action, and good quality cardiopulmonary resuscitation (CPR) contributes to cardiac arrest survival. Our group has recently reported that the quality of professional CPR is substandard in several ambulance services compared to Guidelines recommendations, with too shallow chest compressions and too much time without compressions, even when provided with real-time automated feedback. This thesis is based on manikin and retrospective observational clinical studies where we have measured and analysed quality of CPR to further explore reasons for the gap between Guidelines and actual performance. The change in compression:ventilation ratio from 15:2 to 30:2 introduced in 2005 should increase number of chest compression delivered, but the increased work load might negatively affect quality of chest compressions, especially for lay rescuers with a minimum of training and suboptimal technique. We could not see that lack of physical capability contribute significantly to substandard CPR with a compression:ventilation ratio of 30:2 or less. However, the majority of professional rescuers reported barriers of more psychological or emotional nature that kept them from performing according to Guidelines. This included fear of causing harm when they fractured ribs etc. and three quarters say that they trust their own opinion of what is the right depth and force over automated feedback. Pauses for ventilation contributed less to the high portion of time without compressions than expected, as professional rescuers provided two rescue breaths close to the recommended 4-5 seconds. Decision to transport the patient to hospital with ongoing CPR appeared to influence quality of CPR already on scene, and we conclude that this no longer should be practised