Abstract: A facility for presenting a visual user interface for guiding the performance of a process relating to a patient localization and tracking system is described. The facility displays the user interface in a first state that corresponds to a first process task in an ordered sequence of process tasks. Each time the process task to which the displayed state of the user interface corresponds is completed, the facility redisplays the user interface in a state corresponding to a process task following the process task to which the displayed state of the user interface corresponds.

Abstract: An improved system is disclosed for monitoring a patient's blood chemistry, wherein the system intermittently draws blood samples from the patient into a special sensor assembly having a plurality of analytical sensors, each sensitive to a particular parameter of the blood. After signals produced by these various sensors have been read, the system reinfuses the blood samples back into the patient. Withdrawal of the successive samples to a desired, optimal position within the sensor assembly is achieved by monitoring signals produced by one or more of the analytical sensors, themselves. This allows a catheter that connects the sensor assembly to the patient to have a variable length and internal volume and obviates the need for a separate, dedicated sensor for detecting the arrival of the blood sample at the desired position.