Comparison of two emergency response systems and their effect on survival from out of hospital cardiac arrest.

The pre-hospital care provided by emergency response systems will have an effect on the outcome of patients who have sustained an out of hospital cardiac arrest. This study compares the results of resuscitation in two centres, one in the UK (Edinburgh) and the other in the USA (Milwaukee), and examines the demographics in both centres. An overall greater proportion of patients survived to hospital discharge in Edinburgh, 12.4%, compared with 7.2% in Milwaukee (P < 0.01). However patients were more likely to have a witnessed collapse in Edinburgh 65.7%, compared with 25% (P < 0.001) and significantly more of those patients received bystander cardiopulmonary resuscitation (CPR) 42.3%, compared with 27.1% (P < 0.005). When these two effects are accounted for there is no difference in outcome. The importance of early alerting of emergency services and early bystander CPR should not be underestimated.