[Improved survival by guideline compliant cardiopulmonary resuscitation: analysis of primary survival rates in the Hamburg emergency medical service].

BACKGROUND: In 2005 revised guidelines for cardiopulmonary resuscitation (CPR) were published by the European Resuscitation Council replacing the guidelines implemented in the year 2000. The aim of this study was to test the compliance with valid guidelines and to establish the quality of pre-hospital CPR provided by paramedics over a period of 38 months. PATIENTS AND METHODS: A total of 299 CPRs performed by paramedics of the emergency medical services of Hamburg, Germany between 1(st) November 2004 and 31(st) December 2007 were analyzed. Digital recordings of automated external defibrillators and emergency protocol data were analyzed in detail. CPR was judged as incorrect if the defibrillation energy level did not correspond to the valid guidelines or if the interval between defibrillations exceeded a tolerance range of more than 30% compared to the valid guidelines.
RESULTS: All CPRs (299) were included in the analysis of which 197 (65.9%) were intended to follow the 2000 guidelines and 102 (34.1%) the 2005 guidelines. Return of spontaneous circulation (ROSC) was achieved in 164 cases (54.8%) and survival to hospital admission in 125 cases (41.8%). CPR was performed accurately according to guidelines in only 26 cases (8.7%). In 273 cases (91.3%) the guidelines were not followed completely. Concerning the translation of guidelines into practice most faults occurred due to wrong intervals (89.3%), wrong defibrillation energy (33.4%) and medical errors, such as defibrillating an asystolic patient (7.0%). Primary survival rates were not significantly different when CPR accurately followed the 2000 or 2005 guidelines (40.1% versus 45.1%). Comparing primary survival rates of cases in which the guidelines were followed completely, there was no significant difference between the 2000 guidelines (15 out of 21 cases 71.4%) and 2005 guidelines (4 out of 5 cases 80.0%). However, compliance with valid guidelines significantly increased primary survival rates compared to non-compliance with valid guidelines (19 out of 26 cases 73.1% versus 106 out of 273 cases 38.8%; p=0.007). This effect was independent of the duration of CPR. Comparing CPR with monophasic defibrillation (189 cases) or biphasic defibrillation (58 cases), there was a significantly higher rate of ROSC (56.1% versus 72.4%) and a significantly higher rate of primary survival (41.3% versus 56.9%) in favour of biphasic defibrillation.
CONCLUSION: The results of our study show that compliance with valid guidelines is low and furthermore suggest that compliance with guidelines significantly reduces mortality. Future research may be warranted into the question of how to increase compliance with current CPR guidelines in pre-hospital emergency care.