1. A patient monitoring system comprising: a sensor for measuring values of a physiological parameter; and a processor coupled to said sensor for processing said measured parameter values measured by said sensor, said processor comprising: means for setting target limits of the physiological parameter in response to user selections; means for initiating a target mode after setting of said target limits; means for calculating time-varying dynamic limits based on the current value of the physiological parameter and on the target limits of the physiological parameter; means for comparing said measured parameter values with said dynamic limits in said target mode; and means for generating an alarm when any of said measured parameter values falls outside said dynamic limits.