Abstract
Background and Rationale: Previous studies showed that emergency medical dispatcher (EMD)
infrequently made a correct diagnosis. We found no similar study in Thailand. This study aimed to evaluate
the accuracy of out-of-hospital cardiac arrest (OHCA) diagnosis made by EMD. Methodology: This
was a retrospective study. We reviewed emergency response record from Maharaj Nakorn Chiang Mai
Hospital EMS unit and all records with the diagnosis of OHCA made by EMD at Chiang Mai Province EMS
center from 2011 through 2018. Results: In total, 276 medical records were reviewed. The mean age was
55.3+20.5 years, 72.1% were male, 272 patients had cardiac arrest upon arrival of the EMS team, whereas
4 patients had other conditions. Among these 272 patients, 116 patients (42.6%) were diagnosed with
OHCA by EMD; whereas 86 patients (31.6%) were diagnosed with unconsciousness, 22 (8.1%) with traffic
accident, and 48 (17.6%) with other conditions. The EMD made a diagnosis of OHCA in 120 out of 272
patients, with the sensitivity of 42.6%, and positive predictive value 96.7%. Conclusion: EMD’s diagnosis
of OHCA was inaccurate. However, the diagnosis of OHCA made by EMD had high probability.
