A touchpad controller for a componentized intravascular ultrasound system is disclosed for acquisition and display of intravascular information in a catheter lab environment. The gear unit 33 includes a gearwheel 36 operatively coupled with the worm 38 of the shaft 40 such that rotation of the shaft rotates the gearwheel. Accordingly, a configuration is adopted in which an IO controller makes a selection from among multiple operation modes. The retaining member is coupled with the heat-shrinkable member, and the double-sided printed circuit board is disposed substantially between the retaining member and the component. The medical device is further configured to determine if the dynamic physiological values are sufficiently similar to one another and to grant or deny the monitoring device access to the medical device based on the determination.