Research Project: Software Safety Model for Infusion Pumps
As the complexity of infusion pump design increases, so does the likelihood of their failure. A significant number of these failures are due to a lack of principled engineering practices and associated safety issues. This is particularly true in the case of software based systems, where failure modes are difficult to predict. To address this issue, we are using formal methods to investigate a means of assessing the safe execution of infusion pump software.
The basis of the proposed approach is a model-based engineering development paradigm. In this methodology, software design models are constructed using executable notations that simulate code execution. Once the models are encoded, they can be verified using rigorous mathematical constructs. The verified models can then be used as reference implementations against real world pumps. They can also be extended to study different pump classes and to derive more sophisticated models.
This project advocates the use of such model-based techniques for the engineering of infusion pump software. The base model for the pump, referred to as the generic infusion pump (GIP) is derived from an exhaustive hazard analysis of real-life pump implementations, and is modeled using a hierarchical state machine notation. We will develop a formalism to extend this generic model to more concrete implementations, and demonstrate this approach by deriving models for a patient-controlled analgesia (GPCA) pump and an insulin pump (GIIP) from the base model.