[The nurse providing care to trauma victims in pain: the fifth vital sign].

This qualitative study evaluated nurses' knowledge regarding pain in trauma victims. This study was developed at a public hospital, using a questionnaire and a knowledge test, both of which were treated using Content Analysis. The sample as comprised by 27 nurses, mainly women (92.6%), with an average age of 31±10.3 years and most with less than one year since their graduation (51.8%). Results evinced pain as an unpleasant sensation, a warning sign and a subjective experience. Pain measurement is seen from subjective and objective perspectives. Most nurses (59.3%) are not familiar with the evaluation instruments and, among those with some familiarity, the numerical scale was the most referred. The strategies for pain control mentioned by the nurses were measured as pharmacologic and non-pharmacologic and associated. All nurses considered that pain measurement is important and that is a pathway to a humanized and qualified treatment that guides the therapeutic conduct and reestablished the patients' well-being.