A monitoring device comprising: a part for acquiring an arterial blood pressure signal; and a display; characterised in that the device further comprises: a part for acquiring a signal indicating a level of consciousness; and, a processor or processors arranged: to cause the display to display, in one operating mode and for simultaneous viewing, an image showing the blood pressure signal over time, an image showing cardiac output or stroke volume over time, an image showing systemic vascular resistance over time and an image showing the level of consciousness over time based on the signal indicating the level of consciousness; to record a series of data sets over a period of time, each data set at least comprising a value of said signal indicating a level of consciousness at a time point and one or more of a value of said arterial blood pressure signal at the time point, the cardiac output at the time point, the stroke volume at the time point and the systemic vascular resistance at the time point; and to interpolate between the series of data sets. a part for acquiring an arterial blood pressure signal; and a display; characterised in that the device further comprises: a part for acquiring a signal indicating a level of consciousness; and, a processor or processors arranged: to cause the display to display, in one operating mode and for simultaneous viewing, an image showing the blood pressure signal over time, an image showing cardiac output or stroke volume over time, an image showing systemic vascular resistance over time and an image showing the level of consciousness over time based on the signal indicating the level of consciousness; to record a series of data sets over a period of time, each data set at least comprising a value of said signal indicating a level of consciousness at a time point and one or more of a value of said arterial blood pressure signal at the time point, the cardiac output at the time point, the stroke volume at the time point and the systemic vascular resistance at the time point; and to interpolate between the series of data sets. a part for acquiring a signal indicating a level of consciousness; and, a processor or processors arranged: to cause the display to display, in one operating mode and for simultaneous viewing, an image showing the blood pressure signal over time, an image showing cardiac output or stroke volume over time, an image showing systemic vascular resistance over time and an image showing the level of consciousness over time based on the signal indicating the level of consciousness; to record a series of data sets over a period of time, each data set at least comprising a value of said signal indicating a level of consciousness at a time point and one or more of a value of said arterial blood pressure signal at the time point, the cardiac output at the time point, the stroke volume at the time point and the systemic vascular resistance at the time point; and to interpolate between the series of data sets. to cause the display to display, in one operating mode and for simultaneous viewing, an image showing the blood pressure signal over time, an image showing cardiac output or stroke volume over time, an image showing systemic vascular resistance over time and an image showing the level of consciousness over time based on the signal indicating the level of consciousness; to record a series of data sets over a period of time, each data set at least comprising a value of said signal indicating a level of consciousness at a time point and one or more of a value of said arterial blood pressure signal at the time point, the cardiac output at the time point, the stroke volume at the time point and the systemic vascular resistance at the time point; and to interpolate between the series of data sets.