Strategies to improve survival outcomes of out-of-hospital cardiac arrest (OHCA) given a fixed budget: A simulation study.

BACKGROUND: Our study aimed to identify a strategy that maximizes survival upon hospital discharge or 30-days post out-of-hospital cardiac arrest (OHCA) in Singapore for fixed investments of S$1, S$5, or S$10 million. Four strategies were compared: (1) no additional investment; (2) reducing response time via leasing of more ambulances; (3) increasing number of people trained in cardiopulmonary resuscitation (CPR); and (4) automated external defibrillators (AED). METHODS: We estimated the effect of ambulance response time, bystander CPR and AED on survival based on Singapore's 2010-2015 OHCA registry data. We simulated the changes in ambulance response times and likelihood of (1) CPR and (2) AED usage as a function of their increased availability, which was then combined with the effect of each factor to determine the increase in survival for each strategy. RESULTS: Survival given no additional investment was 4.03% (95% CI: 3.96%, 4.10%). The investments in ambulances, CPR training and AEDs for a given budget of S$1M changed survival to 4.03% (95% CI: 3.96%, 4.10%), 4.04% (95% CI: 3.98%, 4.11%), and 4.44% (95% CI: 4.35%, 4.54%), respectively. This generated 0, 2 and 102 additional life years saved respectively. Given a budget of S$5M or S$10M, 509 or 886 additional life years could be saved, by investing in an additional 10,000 or 20,000 AEDs respectively. The strategies reached a saturation effect whereby improvement in survival was marginal when the budget was increased to ≥S$5M for investment in ambulances and CPR training. CONCLUSIONS: Investing in AEDs had the most gain in survival.

Circadian rhythm in cardiac arrest: the Singapore experience.

INTRODUCTION: There appears to be a circadian rhythm in the timing of cardiovascular and neurovascular events. The majority of studies have been conducted in western populations. This is the first study to look at the peaks and distribution of out-of-hospital cardiac arrest (OHCA) patients in Singapore. METHODS: The Cardiac Arrest and Resuscitation Epidemiology Studies I and II were prospective observation studies on OHCA in Singapore from October 1, 2001 to October 14, 2004. This study analysed data for patients older than 16 years. All data was collected and recorded as per the Utstein style template. Analysis was done for each of the quadrants of the 24-hour clock: 0001-0600, 0601-1200, 1201-1800 and 1801-2400 hours. RESULTS: Of the 2,428 cases, 2,167 OHCA patients qualified for the final analysis. Their mean ages were in the 60s for all the four quadrants, with a male predominance. The two peaks noted were at 0800 and 1900 hours for cardiac causes of death (n = 1,591), and at 0900 and 2000 hours for non-cardiac causes of death (n = 576). At all times of the day, the majority of OHCA occurred in residences and the bystander cardiopulmonary resuscitation rate ranged from 14.6 to 24.3 percent in the different quadrants of the day. CONCLUSION: OHCA has a bimodal distribution in our local cohort of patients. The information obtained will be utilised for fine-tuning emergency medical services strategies, as we strive to improve our current survival rates for OHCA.

Paediatric out-of-hospital cardiac arrests: epidemiology and outcome.

INTRODUCTION: Little information is available regarding the outcome of children in our local population who sustained pre-hospital cardiac arrest. This study was performed to determine the survival rate among children after out-of-hospital cardiac arrest, to describe the epidemiology, and to identify predictors of survival. METHODS: The records of 85 children who presented to a paediatric emergency department in cardiac arrest, between 1 June 1997 and 31 September 2001, were reviewed. The characteristics of the patients, cardiac arrest circumstances, and the outcomes of arrest were analysed. RESULTS: 85 children presented to the emergency department in cardiac arrest during the 52-month study period. 26 out of 85 children (30.6 percent) with cardiac arrest had return of spontaneous circulation (ROSC) after resuscitation efforts at the emergency department. Only four (4.7 percent) survived to be discharged from hospital and three of them survived beyond one year. Two of the cardiac arrest survivors had no change in the neurological status, with the remaining two sustaining severe neurological deficits. Emergency medical service was activated in only 63.7 percent of the patients. 34 percent of the arrests were witnessed, and only 22.9 percent of the children received bystander cardiopulmonary resuscitation (CPR). The positive predictors for survival to hospital discharge in a bivariate analysis were witnessed arrest (p-value is equal to 0.012), presence of bystander CPR (p-value is equal to 0.003), and duration of resuscitation (p-value is equal to 0.028). None who had more than 30 minutes of resuscitation in the emergency department survived. In a multivariate analysis with a logistic regression model, the only two independent predictors of ROSC were witnessed arrest (odds ratio is 3.049; 95% confidence interval [CI] is 1.101-8.444; p-value is equal to 0.032) and duration of resuscitation (odds ratio is 0.353; 95% CI is 0.146 - 0.854; p-value is equal to 0.021). CONCLUSION: Out-of-hospital cardiac arrest in children has a poor prognosis and prolonged resuscitation at the emergency department beyond 30 minutes does not improve survival.