As computers become more and more an aid in the management of medical information, some specialists, such as anesthesiologists, demand tuned applications to support their own activity. The development of these specific applications is based upon the user's requirements analysis, and functional and technical specifications. But some failures show that a better understanding of human factors of acceptance could improve the usability and utility of these tools. In this study, we demonstrated that when the management of medical information is closely intertwined with the physician's activity, it is necessary to perform a precise analysis of this activity in order to identify the cognitive and organizational constraints that affect the usability and acceptance of the tool. We focused our study on the pre-operative anesthetic consultation. After recording and analyzing 50 consultations, we were able to identify the key points to fulfill in order to meet users' acceptance. From this study, we propose some strong recommendations to handle the constraints imposed by the anesthesiologists' activity in their daily working environment. We applied this method to evaluate an electronic patient record (EPR) for the pre-anesthetic consultation. The results of this evaluation validate our hypotheses and the importance of the activity constraints. In conclusion, human factors, and particularly those linked with the activity of healthcare professionals, have to be carefully studied before any development and installation of an EPR into a specialty domain.