Limitations
SECONDARY
To mitigate selection bias, complete randomisation was used to balance allocation. Nevertheless, we cannot explain the difference in number of erroneous calls between the two groups.Detection bias could not be excluded, as knowledge of the randomisation might have affected documentation of the primary endpoint, although a blinded assessment was implemented. In addition, paramedic EMS files differed from physician files, which might have led to different documentation for patients without physician contact per se and might have introduced performance bias. In cases without physician contact, we could only evaluate the paramedic EMS-file. The higher number of missing EMS-files in the tele-group might be explained by the lower willingness among the paramedics to write a protocol than among physicians.We acknowledge a relatively high loss to follow-up for the secondary 30- and 90-day outcome. One reason is that in Germany only a physically present physician may obtain a written informed consent. Thus, it could only be sought in both groups for conveyed patients to the hospital, albeit it was missed in several cases due to organisational reasons.One major limitation is the discrepancy between our estimated and observed number of AEs.Further, our secondary outcomes have to be considered carefully, as our study was not powered for any of them. Moreover, we acknowledge that our results for cases with physician contact have not reached the non-inferiority sample size and we did not perform a sample size calculation to demonstrate superiority.