Combative Patients

I am a student nurse attending school in Nevada. We were assigned to finding topics that interest us and finding out more information from experienced nurses on a listserv. I currently am an EMT that works in the ER, and i have been attacked twice in the year and a half that i have worked there. Upon research I found that a study published by Rolf Wynn, MD and Trond Bratlid, MD published in the Scand J Caring Science Journal in 1998 71% of psychiatric nurses have been attacked, and a majority of the time it was while trying to restrain a patient. Both times that i have been attacked it was trying to restrain a psych patient. The question that this long introduction is getting to is what are some tricks of the trade to help ED nurses prevent attacks when dealing with combative patients. What differences do you have to make when working with the psych patients? Thank you in advance for your responses.