Vital signs interpretation is an important element of patient monitoring. The use of visualisation could enhance this interpretation. We present a model for time-based visual analytics visualisation of vital signs. Our model allows for multiple vital signs to be charted along a time-based axis. The patient management care team then can apply lenses to alter the view being presented of the data, allowing the viewer to understand the meaning and improve the interpretation. The lenses applied will allow for generalisation, refinement, and traversing.