Pre-hospital communication is a critical first step towards ensuring efficient management of critically injured patients during trauma resuscitation. Information about incoming patients received from the field and en route serves a critical role in helping emergency medical teams prepare for patient care. Despite many efforts, inefficiencies persist. In this paper, we examine the pre-hospital communications between pre-hospital and hospital providers, including the types of information transferred during en-route calls, as well as the information needs of trauma teams. Our findings show that Emergency Medical Services (EMS) teams report a great deal of information from the field, most of which match the needs of trauma teams. We discuss design implications for a computerized system to support the use and retention of pre-hospital information during trauma resuscitation.