Effects of Early Defibrillation by Ambulance Personnel on Short- and Long-term Outcome of Cardiac Arrest Survival

The Munich Experiment

¹ From the Institut und Poliklinik für Psychosomatische Medizin, Med Psychologie und Psychotherapie, des Klinikums Rechts der Isar der Technischen Universität München; MEDIS Institut der GSF, Forschungszentrum für Umwelt und Gesundheit, München-Neuherberg
² From the Institut und Poliklinik für Psychosomatische Medizin, Med Psychologie und Psychotherapie, des Klinikums Rechts der Isar der Technischen Universität München
³ From the Institut für Anästhesiologie, des Klinikums Rechts der Isar der Technischen Universität München
⁴ From the I. Medizinische Klinik, des Klinikums Rechts der Isar der Technischen Universität München
⁵ From the Bayerisches Rotes Kreuz
⁶ From the Arbeiter-Samariter-Bund, Coordinator of the Munich Early Defibrillation Program

Objectives: This study evaluates the feasibility of implementing early defibrillation of out-of-hospital cardiac arrest patients for basic life-support providers (EMT-D) in a two-tier emergency system in the city of Munich, Germany.

Design: Retrospective consecutive analysis of all EMT-D attempts during a 5-year initiation phase (1990 to 1994) and prospective follow-up of all cardiac arrest survivors discharged from hospital.

Setting: A strictly defined inner-city and suburban area of 978 km² and a residential population of 1,530,000 inhabitants with 22 ICUs in urban hospitals. One dispatching center to alert a two-tier emergency system with 56 EMT-D-staffed ambulances and physician-staffed mobile ICUs stationed at the nearest of nine hospitals.

Methods: All EMT-D cases were identified and data on patients were documented in a standardized manner from patients' records, including the resuscitation protocol in the hospitals to which the patients were referred. For those patients discharged from the hospital, a standardized telephone interview was undertaken with the physician in charge of the patient and with the patient/relative leading to an assessment of the patient's status according to the Glasgow-Pittsburgh cerebral performance categories.

Intervention: None.

Results: During the 5-year initiation phase of the EMT-D program in the two-tier emergency system in Munich, there were 243 resuscitation attempts by EMTs, using the semiautomated defibrillator; 125 patients died immediately on the scene. In 118 patients, spontaneous circulation was reestablished and these patients were admitted to an ICU in 1 of the 22 urban hospitals. Median call-response interval for the EMT-D was 5 min (interquartile range, 3 to 6) and was 10 min (interquartile range, 7 to 13) for the second tier (p0.0001). In 34 cases (28.8%), EMT-D staff had reestablished spontaneous circulation (ROSC) before the second tier arrived on the scene. Patients with ROSC on the arrival of the second tier were more frequently discharged alive from hospital than were patients without ROSC at that time (p0.0001). The hospital discharge rate of initially successful resuscitated patients presenting with out-of-hospital ventricular fibrillation was 38.1% (45/118). Overall success rate of all EMT-D attempts was 18.5% (45/243). After a mean follow-up time of 39 (range, 22 to 64) months, 29 (66%) patients were still living. Twenty-five (56.8%) were neurologically not disabled or mildly disabled (CPC 1/2); disability was moderate in 3 (6.8%) patients and was severe in 1 (2.3%) patient. One case was lost to follow-up.

Conclusion: The present study demonstrates that the upgrading of basic life support providers with semiautomated defibrillators has a significant benefit for cardiac arrest victims outside the hospital in an urban environment.

Key Words: cardiopulmonary resuscitation • early defibrillation • out-of-hospital cardiac arrest

Submitted on May 12, 1997
Accepted on July 2, 2007

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