Feasibility of 10-Minute Arrival Time to Departure Time Metric for STEMI Patients

Delays in reperfusion treatment in ST-elevation myocardial infarction (STEMI) patients leads to higher morbidity and mortality. Previous reports for Helicopter Emergency Medical Services (HEMS) suggests a 10-minute skid-to-skid (arrival to departure) time to achieve appropriate reperfusion times. However, there is no published data on whether this goal is achievable for a HEMS service. This study aims to see if a midwestern critical care service can consistently achieve a 10-minute helicopter skid-to-skid time or ground critical care service arrival to departure time. Further, comparing this metric between ground and helicopter transportations will help evaluate the ideal transportation method to optimize time to percutaneous intervention (PCI).

This was a retrospective chart review utilizing 10 years of data from our ground and HEMS program to assess whether a 10-minute arrival to departure time for STEMI patients could be achieved. Patients included were at least 18 years of age and were transported from the referring facility for further STEMI management. Wilcoxon rank sum test and Chi-square tests were used to evaluate data between helicopter and ground services.

Included in the study were 686 patients, 608 by helicopter transport and 78 by ground transport. The median arrival to departure time was 14 min (IQR = 5) for helicopter patients and 13 min (IQR = 6) for ground patients. There was not a statistically significant difference in this metric for STEMI patients transported by helicopter versus ground. A statistically significant difference, though, existed between helicopter and ground transports among percent with times less than or equal to 10 min versus percent times greater than 10 min, X² = 5.46, df = 1, p = 0.02. Two referring facilities had statistically significant differences in median arrival to departure times.

Our study found that a median EMS arrival to departure time of 10 min to transport STEMI patients was not consistently achieved via either helicopter or ground transportation.