A patient is monitored using a monitoring apparatus including a remote monitoring unit associated with the patient and having a sensor that measures a physiological characteristic of the patient, a central unit, and a communications device which selectively establishes a communications link between the remote monitoring unit and the central unit. The remote monitoring unit obtains a monitored data set for the patient, analyzes the monitored data set to obtain a derived data set from the monitored data set, and determines from the derived data set that communication with the central unit is required. A communications link is established with the central unit, and the remote monitoring unit transmits to the central unit an initially transmitted data set related to the monitored data set. The central unit analyzes the initially transmitted data set and instructs the remote monitoring unit as to any additional transmitted data set related to the monitored data set that is to be transmitted from the remote monitoring unit to the central unit and a time at which the additional transmitted data set is to be transmitted.
