sbrttn, Good luck, since you have not specified the level, I am assuming you are seeking to do a disseratation for a pHD?? Why not combine both of your areas of interest and expertise and investigate nursing educational issues in the E.D.? More specifically, why not investigate developing a model, process or etc. for education of nurses in triage in the E.D. this could also take the form of a (qualitative) grounded theory study into the the development of expertise of E.D. nurses in the skills of triage within the emergency setting. Another area that probably is begging for investigation is that of skills of nurses in the management of aggressive patients within this environment. A recent study here in Australia has ranked nurses up there with police, prostitutes, and taxi drivers as recipients of violence from those for whom they care, particularly in the E.D. This is certainly an area currently lacking in education of nursing students and within Emergency Certificate courses in this country, but the literature would indicate that this lack is more global (both the UK and US literature).
You need to obviously be specific about which research methods you prefer: qualitative or quantitative, or if you are allowed to do a systematic critical review of the literature. Hopefully, you will explore these areas thoroughly with academic supervisors of the proposed institution/program for which you are applying, since not all institutions offer support for all types of topics and research methodologies. It is very much a case of finding the right supervisor with the right expertise, topically and methodologically, as well as a 'fit' of personanalities, since your work and efforts will be very much influenced by their previous work and biases. Sometimes students have been more successful with co-supervision between supervisors within say Schools of Nursing and Schools of Behavioural Science or Education, depending upon your final choice of topic.
Again all the best!!! Let me know how you go.