Impact of two-level filtering on emergency medical communication center triage during the COVID-19 pandemic: an uncontrolled before-after study

Rapid access to emergency medical communication centers (EMCCs) is pivotal to address potentially life-threatening conditions. Maintaining public access to EMCCs without delay is crucial in case of disease outbreak despite the significant increased activity and the difficulties to mobilize extra staff resources. The aim of our study was to assess the impact of two-level filtering on EMCC performance during the COVID-19 outbreak.

A before-after monocentric prospective study was conducted at the EMCC at the Nantes University Hospital. Using telephone activity data, we compared EMCC performance during 2 periods. In period one (February 27th to March 11th 2020), call takers managed calls as usual, gathering basic information from the caller and giving first aid instructions to a bystander on scene if needed. During period two (March 12th to March 25th 2020), calls were answered by a first-line call taker to identify potentially serious conditions that required immediate dispatch. When a serious condition was excluded, the call was immediately transferred to a second-line call taker who managed the call as usual so the first-line call taker could be rapidly available for other incoming calls. The primary outcome was the quality of service at 20 s (QS20), corresponding to the rate of calls answered within 20 s. We described activity and outcome measures by hourly range. We compared EMCC performance during periods one and two using an interrupted time series analysis.

We found that rapid access to our EMCC was maintained during the COVID-19 pandemic via two-level filtering. This system helped reduce the time gap between call placement and first-line call-taker evaluation of a potentially life-threatening situation. We suggest implementing this system when an EMCC faces significantly increased activity with limited staff resources.