a patient monitoring system has a processor and a spectrophotometric sensor . the sensor is configured to be affixed to a patient to communicate signals associated with real time spectrophotometric measurements to the processor . the system further includes memory for storing data and computer instructions . the processor is configured to execute instructions stored in the memory to calculate a trend statistic based on a group of the signals received from the sensor . the processor is further configured to execute instructions stored in the memory to cause real time information associated with the spectrophotometric measurements and information associated with the trend statistic to be displayed on a visual user interface .