Prehospital Advanced Cardiac Life Support with a Smartphone-Based Direct Medical Oversight in a Metropolitan City, Korea

Out-of-hospital cardiac arrest is considered an important health care problem since it causes family breakdown and enormous social loss due to sudden death. Despite the efforts of many medical policy makers, paramedics, and doctors, the survival rate after cardiac arrest is only marginally increasing.

This study aimed to determine whether advanced life support (ALS) under physician’s direct medical oversight during an emergency through video call on smartphones was associated with improved out-of-hospital cardiac arrest (OHCA) outcomes on the "Smart Advanced Life Support (SALS)" pilot project.

This study was conducted using a "Before-After" controlled trial. The OHCA patients were divided into two periods in a metropolitan city. The basic life support (BLS group) and ALS using video calls on smartphones (SALS group) were performed in the 'Before' and 'After' phases in 2014 and 2015, respectively. The OHCA patients over 18 years of age were included in this study. On the other hand, the patients with trauma, poisoning, and family’s unwillingness, as well as those who received no resuscitation were excluded from the study. The primary and secondary outcomes were survival to discharge and a good neurological outcome (cerebral performance category [CPC] 1-2), respectively. A propensity score matching was conducted to equalize potential prognostic factors in both groups. The adjusted odds ratio (OR) and 95% confidence interval (95% CI) were calculated for survival to discharge and good neurological outcome.

In total, 235 and 198 OHCA patients were enrolled in the BLS and the SALS groups, respectively. The outcomes were better in the SALS group, compared to the BLS group regarding the survival to discharge (9.8% vs. 6.8%, P<0.001) and good neurological outcome (6.6% vs. 4.0%, P<0.001), respectively. Regarding propensity score matching, 304 cases were randomly assigned to the SALS and BLS groups. The survivals to discharge rates after matching were 9.2% and 7.2% in the SALS and the BLS groups, respectively (P=0.06). Furthermore, the good neurological outcome rate was 5.9% in the SALS group versus 3.9% in the BLS group (p=0.008). The adjusted ORs of the SALS group were estimated at 1.33 (95% CI: 1.00-1.77) for survival to discharge and 1.73 (95% CI: 1.19-2.53) for the good neurologic outcome, compared to those in the BLS group.

An emergency medical system intervention using the SALS protocol was associated with a significant increase in prehospital ROSC and improved survival and neurologic outcome after OHCA.