OBJECTIVES:

The published Pan-Asian Resuscitation Outcomes (PAROS) study identified several modifiable factors that improve OHCA survival. These include shorter ambulance response time, bystander cardiopulmonary resuscitation (CPR), and pre-hospital defibrillation performed by automated external defibrillator (AED). This study aimed to identify a strategy that maximizes improvements in survival upon hospital discharge or 30-days post OHCA in Singapore for a one-time investment of $10, $20, or $30 million put toward one of the following strategies 1) reducing response time via purchase of more ambulances 2) increased CPR training; 3) greater investment in AEDs.

METHODS:

We first determined the number of additional ambulances, CPR trainings, and AEDs that could be purchased with a given budget. We then simulated the changes in ambulance response time, and likelihood of 1) CPR and 2) AED usage as a function of their increased availability. We then combined this information with odds ratios for increasing survival to hospital discharge of each factor estimated from PAROS Singapore 2010-2015 data to determine the increase in survival probability from each investment strategy.

RESULTS:

Odds ratios for ambulance response time (for each additional minute), bystander CPR and bystander defibrillation were 0.87 (95% CI: 0.82-0.94, p<0.001), 1.38 (95% CI: 1.11-1.71, p=0.003), 3.13 (95% CI: 2.06-4.63, p<0.001). Survival at baseline was 4.03% (95% CI: 3.96%-4.10%). Predictive survival for the three strategies given a budget of $10M were 4.25% (95% CI: 4.18%-4.33%), 4.09% (95% CI: 4.03%-4.16%), and 4.84% (95% CI: 4.73%-4.95%) for ambulance, CPR and AED investments, respectively. Increasing the budget to $30M improved survival to 4.40%, 4.22%, and 6.47% which represents 7, 4, and 50 additional lives saved for three strategies respectively.

CONCLUSIONS:

Investment into either of three strategies given a budget of 10M slightly improved survival. When the budget was increased to 20M and 30M, survival was further improved. Increasing number of AEDs achieved the highest survival.