Studies were searched in Medline, using PubMed with the search terms 'emergency' and 'pain protocol'. This search was last performed on May 22nd 2020 and yielded 2479 hits.
Eventually, studies in which the authors described the implementation of a pain protocol in the Emergency Department were selected. Study populations consisted of adult patients (or mixed study populations including younger patients), regardless of disease or condition. Study type didn't matter for inclusion in this review, studies did not require a comparison (as long as the 'after-implementation' study period was reported).
This search strategy resulted in a total of 28 studies that were critically appraised according to the OCEBM levels of evidence. Additionally, these levels of evidence were used to state a level of recommendation after analyzing several studies describing the same endpoint.
Almost all studies used different study methods, evaluated different study populations with in- and exclusion criteria and evaluated several different outcomes. Moreover, these outcomes were measured at different endpoints. These distinct features of all studies included in this review made it not possible to pool study results and the current review cannot be regarded as a systematic review with a meta-analysis.
Besides, all studies reported different types of a pain protocol. Therefore, the choice was made to analyze studies together based on the type of pain protocol that was described. This resulted in the distinction of 3 types: 'nurse-initiated', 'nurse-driven' and a 'pain protocol in general'. In a way this makes the most sense, as time to analgesia and safety might be more important in a nurse-initiated pain protocol as (triage) nursing staff might administer opioid analgesics completely autonomously. However, it should be noted that although it was not explicitly described in studies evaluating a 'pain protocol in general', some might have been nurse-driven or even nurse-initiated as well.