This paper describes the human computer interface of a new emergency medical services application, which uses several emerging technologies to clarify the inherent complexity and uncertainty of emergency pre-hospital patient care. These technologies include: 1) the integration and display of real-time physiological sensor data in parallel with manually entered human observations and treatments; 2) a meta-data approach to screen definitions to allow dynamic configuration; and 3) a rule-based data capture system to ensure complete and accurate data collection. These new technologies led us to design a flexible and efficient GUI that is capable of evolving as technology and medical science advance.