An observational study describing the geographic-time distribution of cardiac arrests in Singapore: what is the utility of geographic information systems for planning public access defibrillation? (PADS Phase I).

INTRODUCTION: Public access defibrillation (PAD) has shown potential to increase cardiac arrest survival rates. OBJECTIVES: To describe the geographic epidemiology of prehospital cardiac arrest in Singapore using geographic information systems (GIS) technology and assess the potential for deployment of a PAD program. METHODS: We conducted an observational prospective study looking at the geographic location of pre-hospital cardiac arrests in Singapore. Included were all patients with out-of-hospital cardiac arrest (OHCA) presented to emergency departments. Patient characteristics, cardiac arrest circumstances, emergency medical service (EMS) response and outcomes were recorded according to the Utstein style. Location of cardiac arrests was spot-mapped using GIS. RESULTS: From 1 October 2001 to 14 October 2004, 2428 patients were enrolled into the study. Mean age for arrests was 60.6 years with 68.0% male. 67.8% of arrests occurred in residences, with 54.5% bystander witnessed and another 10.5% EMS witnessed. Mean EMS response time was 9.6 min with 21.7% receiving prehospital defibrillation. Cardiac arrest occurrence was highest in the suburban town centers in the Eastern and Southern part of the country. We also identified communities with the highest arrest rates. About twice as many arrests occurred during the day (07:00-18:59 h) compared to night (19:00-06:59 h). The categories with the highest frequencies of occurrence included residential areas, in vehicles, healthcare facilities, along roads, shopping areas and offices/industrial areas. CONCLUSION: We found a definite geographical distribution pattern of cardiac arrest. This study demonstrates the utility of GIS with a national cardiac arrest database and has implications for implementing a PAD program, targeted CPR training, AED placement and ambulance deployment.

Comparison of termination-of-resuscitation guidelines for out-of-hospital cardiac arrest in Singapore EMS.

CONTEXT: Termination of resuscitation (TOR) in the field for out-of-hospital cardiac arrest (OHCA) can reduce unnecessary transport to hospital and increase availability of resources for other patients. OBJECTIVES: To compare the performance of three TOR guidelines for Basic Life Support-Defibrillator (BLS-D) providers when applied to cardiac arrest patients in the Cardiac Arrest and Resuscitation Epidemiology (CARE) study. DESIGN: This prospective cohort study involved all OHCA patients attended by BLS-D providers in a large urban center. The data analyses were conducted secondarily on these prospectively collected data. Three TOR guidelines proposed by Marsden et al. [BMJ 1995;311:49-51], Petrie [CJEM 2001;3:186-92] and Verbeek et al. [Acad Emerg Med 2002;9:671-8] were applied to show the relationship between the guidelines and actual survival. RESULTS: From 1 October 2001 to 14 October 2004, 2269 patients were enrolled into the study. Thirty-two (1.4%) survived to hospital discharge. For the 3 TOR guidelines, sensitivity was 93.8% (95%CI=79.9-98.3) (Petrie), 81.3% (95%CI=64.7-91.1) (Verbeek) and 90.6% (95%CI=75.8-96.8) (Marsden). Negative predictive value was 99.7% (95%CI=99.0-100.0) (Petrie), 99.6% (95%CI=99.2-99.8) (Verbeek) and 99.8% (95%CI=99.4-99.9) (Marsden). Application of these guidelines would have resulted in transport of 68.4% (Petrie), 31.3% (Verbeek) and 36.1% (Marsden) of cases. The Petrie guidelines would have recommended TOR in two patients who eventually survived. Similarly TOR was recommended in six patients for Verbeek and three patients for Marsden who eventually survived. CONCLUSION: We found all three TOR guidelines to have high sensitivity and negative predictive value. However the specificity and transport rates varied greatly. Application of any TOR guidelines may be affected by local EMS and population factors which should be considered in any policy decision.

Survival outcomes with the introduction of intravenous epinephrine in the management of out-of-hospital cardiac arrest.

STUDY OBJECTIVE: The benefit of epinephrine in cardiac arrest is controversial and has not been conclusively shown in any human clinical study. We seek to assess the effect of introducing intravenous epinephrine on the survival outcomes of out-of-hospital cardiac arrest patients in an emergency medical services (EMS) system that previously did not use intravenous medications. METHODS: This observational, prospective, before-after clinical study constitutes phase II of the Cardiac Arrest and Resuscitation Epidemiology project. Included were all patients who are older than 8 years, with nontraumatic out-of-hospital cardiac arrest conveyed by the national emergency ambulance service. The comparison between the 2 intervention groups for survival to discharge was made with logistic regression and expressed in terms of the odds ratio (OR) and the corresponding 95% confidence interval (CI). RESULTS: From October 1, 2002, to October 14, 2004, 1,296 patients were enrolled into the study, with 615 in the pre-epinephrine and 681 in the epinephrine phase. Demographic and EMS characteristics were similar in both groups. Forty-four percent of patients received intravenous epinephrine in the epinephrine phase. There was no significant difference in survival to discharge (pre-epinephrine 1.0%; epinephrine 1.6%; OR 1.7 [95% CI 0.6 to 4.5]; adjusted for rhythm OR 2.0 [95% CI 0.7 to 5.5]); return of circulation (pre-epinephrine 17.9%; epinephrine 15.7%; OR 0.9 [95% CI 0.6 to 1.2]), or survival to admission (pre-epinephrine 7.5%; epinephrine 7.5%; OR 1.0 [95% CI 0.7 to 1.5]). There was a minimal increase in scene time in the epinephrine phase (10.3 minutes versus 10.7 minutes; 95% CI of difference 0.02 to 0.94 minutes). CONCLUSION: We were unable to establish a significant survival benefit with the introduction of intravenous epinephrine to an EMS system. More research is needed to determine the effectiveness of drugs such as epinephrine in resuscitation.

Out-of-hospital cardiac arrests occurring in primary health care facilities in Singapore.

OBJECTIVES: To study out-of-hospital cardiac arrests (OHCA) occurring in primary healthcare facilities (HCF) in Singapore and to compare these with arrests occurring in the community. METHODS: This prospective observational study was part of the Cardiac Arrest and Resuscitation Epidemiology (CARE) project. Included were all patients with OHCA occurring in HCF. Patient characteristics, cardiac arrest circumstances, EMS response and outcomes were recorded according to the Utstein style. RESULTS: From 1 October 2001 to 14 October 2004, the data from 2428 subjects were received of which 138 patients were OHCA occurring in HCF. This is an incidence of 1.12/100,000 population per year and constituted 6.0% of all OHCA. Arrest occurring in HCF were more likely to be witnessed (p<0.01), or have bystander CPR (p<0.01). The HCF group was also more likely to receive CPR with both compression and ventilation (p<0.01) and have a non-trauma cause of arrest (p=0.03). HCF arrests also had a shorter collapse to call (EMS number) than the non-HCF group (HCF 1.54min versus non-HCF 5.36min, p=0.01). However, no HCF patient received defibrillation prior to EMS arrival. HCF patients were more likely to have return of spontaneous circulation at any time (p=0.05), survival to hospital admission (p<0.01) and survival to discharge (p<0.01) compared to non-HCF patients. CONCLUSION: This study suggests that primary health care providers do have an important role locally in managing out-of-hospital cardiac arrest. We propose an initiative to encourage early defibrillation by primary health care providers.

New paradigm for protection: the emergency ambulance services in the time of severe acute respiratory syndrome.

Severe acute respiratory syndrome (SARS) is a newly emerging and highly infectious form of atypical pneumonia with a high rate of transmission, especially among health care workers. With SARS, certain policies had to be implemented rapidly by the emergency ambulance services and the Ministry of Health to support and protect all personnel adequately. The authors discuss the changes in policies and personnel behavior, the training and education that had to be disseminated widely, and certain alternatives in policies such as transportation. The authors hope to share their experience in the implementation of these strategies by the Singapore Civil Defence Force and stress the importance of the psychological preparedness of the paramedics and prehospital care providers worldwide in this era of SARS.