Implementing health information technology (HIT) is a challenge that frequently results in unintended consequences post implementation. To better manage these consequences we need approaches that can proactively identify issues so we deal with them pre-implementation. It can be suggested that a reason unintended consequences occur is because of trade-offs between people's work practices and pre and post HIT implementation. If we can identify what these trade-offs are we can use them for proactive management of unintended consequences. This paper uses a case study of a perioperative information system and principles of social BPM and qualitative content analysis to develop a model of seven trade-off patterns that can be used to study HIT mediated change. It also discusses the implications of the model on the design and evaluation of HIT.