Background: 
Dispatch-assisted cardiopulmonary resuscitation could improve survival of out of hospital cardiac arrest (OHCA) patient. However, there were many barriers between dispatch and bystander. Our study aimed to determine the effectiveness of dispatch-assisted cardiopulmonary resuscitation from different dialing methods.

Method: 
This is a retrospective cohort study. Patients with OHCA between May 1, 2017 and May 31, 2018 In Taichung City were enrolled. According to the dialing method, mobile phone or telephone, the patients were divided into 2 groups.  We compared clinical outcome ( ROCS rate and survival to discharge rate ), the initial time and success rate of CPR recognized, CPR instruction, Chest compression, and CPR terminate after EMS arrival. 

Result:
Mobile phone group had 814 patients and telephone group had 1369 patients. Comparing between mobile phone group and telephone group, the former had shorter initial CPR instruction time ( median: 90 sec, 95%: 98.4-112.1 sec v.s. median: 115 sec, 95%: 113.2-157.3 sec. p = 0.11 ), shorter first chest compression time ( median: 152 sec, 95%: 159.3-174 sec v.s. median 178 sec, 95%: 184.2-197.3 sec. p < 0.001 ) and higher chest compression rate ( 95.7% v.s. 86%, p < 0.001 ). However, the former had longer CPR termination time ( median: 473 sec, 95%: 466-507 sec v.s. median: 425, 95%: 423-456 sec, p < 0.001 ) because EMT arrived the scene slower.

Conclusion:
Calling the dispatch center via the mobile phone can raise compression rate and shorten the compression time compared to telephone. However, obstacles in GPS positioning should be overcome to further improve clinical outcomes.

1 - Different Dialing Method Affect the Effect of Dispatch-Assisted Cardiopulmonary Resuscitation.