In acute care hospital settings, nurses routinely interact with a wide range of medical devices, each with its own unique user interface. While individual medical device usability has been studied, much less attention has been given to how nurses must manage and coordinate care using multiple devices with different and sometimes conflicting interface designs. This paper introduces the emerging phenomenon of Inter-User Interface Friction to describe the act of coordinating care across multiple medical device interfaces designs that are not aligned and inconsistent. Through an evaluation of ten routinely used medical devices at a teaching hospital in Northern Ontario, Canada, key interface discrepancies were identified. Despite focusing only on non-specialized medical devices and basic device interaction features, the findings reveal a striking level of inconsistency in how information is presented and actions are performed. These variations can lead to hindering efficiency and user satisfaction, increase cognitive load, and compromise safe patient care.