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Objectives: This study aimed to determine if a deployment strategy based on geospatial-time analysis is able to reduce ambulance response times for out-of-hospital cardiac arrests (OOHCA) in an urban emergency medical services (EMS) system.Methods: An observational prospective study examining geographic locations of all OOHCA in Singapore was conducted. Locations of cardiac arrests were spot-mapped using a geographic information system (GIS). A progressive strategy of satellite ambulance deployment was implemented, increasing ambulance bases from 17 to 32 locations. Variation in ambulance deployment according to demand, based on time of day, was also implemented. The total number of ambulances and crews remained constant over the study period. The main outcome measure was ambulance response times.Results: From October 1, 2001, to October 14, 2004, a total of 2,428 OOHCA patients were enrolled into the study. Mean ± SD age for arrests was 60.6 ± 19.3 years with 68.0% male. The overall return of spontaneous circulation (ROSC) rate was 17.2% and survival to discharge rate was 1.6%. Response time decreased significantly as the number of fire stations ⁄ fire posts increased (Pearson v 2 = 108.70, df = 48, p < 0.001). Response times for OOHCA decreased from a monthly median of 10.1 minutes at the beginning to 7.1 minutes at the end of the study. Similarly, the proportion of cases with response times < 8 minutes increased from 22.3% to 47.3% and < 11 minutes from 57.6% to 77.5% at the end of the study. Conclusions:A simple, relatively low-cost ambulance deployment strategy was associated with significantly reduced response times for OOHCA. Geospatial-time analysis can be a useful tool for EMS providers.ACADEMIC EMERGENCY MEDICINE 2010; 17:951-957 ª 2010 by the Society for Academic Emergency MedicineKeywords: geographic information systems, heart arrest, emergency medical services G eographic information systems (GIS) are computer-based systems for the integration and analysis of geographic data. GIS is a multilayering mapping software that is able to portray multiple geographic-time information in an easy-to-read, graphical manner. ''Geographic data'' are spatial data that result from observation and measurement of phenomena referenced to their locations on the earth's surface.

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Objectives: The new Vancouver Chest Pain (VCP) Rule recommends early discharge for chest pain patients who are at low risk of developing acute coronary syndrome (ACS), and thus can be discharged within 2 hours of arrival at the emergency department (ED). This study aimed to assess the performance of the new VCP Rule for Asian patients presenting with chest pain at the ED. Methods: This prospective cohort study involved patients attended to at the ED of a large urban centre. Patients of at least 25 years old, presenting with stable chest pain and a non-diagnostic ECG, and with no history of active coronary artery disease were included in the study. The main outcome measures were cardiac events, angioplasty, or coronary artery bypass within 30 days of enrolment. Results: The study included 1690 patients from 27 August 2000 to 1 May 2002, with 661 patients fulfilling the VCP criteria. Of those for early discharge, 24 had cardiac events and 13 had angioplasty or bypass at 30 days, compared to 91 and 41, respectively, for those unsuitable for discharge. This gave the rule a sensitivity of 78.1% for cardiac events, including angioplasty and bypass. Specificity was 41.0%, and negative predictive value (NPV) was 94.4%. Conclusion: We found the new VCP Rule to have moderate sensitivity and poor specificity for adverse cardiac events in our population. With an NPV of less than 100%, this means that a small proportion of patients sent home with early discharge would still have adverse cardiac events. RÉSUMÉObjectifs: Selon la nouvelle règle de Vancouver sur la douleur thoracique, il est recommandé que les patients qui présentent des douleurs thoraciques mais qui connaissent un faible risque de syndrome coronarien aigu puissent être renvoyés peu de temps après leur arrivée au service des urgences (SU), soit dans les deux heures suivantes. L'étude visait à évaluer la performance de la nouvelle règle de Vancouver chez des patients d'origine asiatique présentant des douleurs thoraciques, au SU. Méthode: Il s'agit d'une étude de cohorte, prospective, à laquelle ont participé des patients traités dans un SU d'un important centre urbain. Ont été sélectionnés des patients âgés d'au moins 25 ans, qui présentaient une douleur thoracique stable mais chez qui l'ECG s'est révélé non concluant et qui n'avaient pas d'antécédents de coronaropathie active. Les principaux critères d'évaluation consistaient en la survenue d'événements cardiaques ou encore en la réalisation d'une angioplastie ou d'un pontage coronarien dans les 30 jours suivant l'inclusion dans l'étude. Résultats: Au total, 1690 patients ont participé à l'étude, du 27 août 2000 au 1 er mai 2002, dont 661 répondaient aux critères de la nouvelle règle de Vancouver. Parmi ceux qui ont été renvoyés peu de temps après leur arrivée, 24 ont subi un événement cardiaque et 13 autres, une angioplastie ou un pontage coronarien au bout de 30 jours contre 91 et 41 respectivement parmi ceux qui n'étaient pas en état de quitter l'hôpital. Ainsi, la sensibilité de la règle s'est étab...

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