Hijacking the dispatch protocol: When callers pre-empt their reason-for-the-call in emergency calls about cardiac arrest

This article examines emergency ambulance calls made by lay callers for patients found to be in cardiac arrest when the paramedics arrived. Using conversation analysis, we explored the trajectories of calls in which the caller, before being asked by the call-taker, said why they were calling, that is, calls in which callers pre-empted a reason-for-the-call. Caller pre-emption can be disruptive when call-takers first need to obtain an address and telephone number. Pre-emptions have further implications when call-takers reach the stage when they are required to deliver the scripted turn tell me exactly what happened'. When there has been a pre-emption earlier on, callers tend to treat the scripted turn as a request for more information and may not repeat their reason-for-the-call. This can occasion delays and important information can be lost. We identified an effective alternative strategy used by some call-takers, pre-emption repeat, which callers treat as a request for confirmation.