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IV. GENERAL OVERVIEW
The 90XL meter is a portable, multifunction meter designed to measure the conductivity, pH,
temperature, and pressure of the dialysate fluids associated with hemodialysis delivery systems,
and of the water used in hemodialysis.
The display module houses the electronic circuitry, navigation keys, digital display, and
rechargeable lithium-ion battery. The four navigation keys are labeled by the display according to
context.
The individual sensor modules contain the appropriate sensors and circuitry for measuring the
desired parameter of the dialysate solution or hemodialysis water. The sensor modules attach to
the display module with cables that plug into connectors on the meter. Up to four different sensor
modules may be simultaneously connected to the display module for the desired measurements.
Measurements for conductivity and temperature are taken as the solution flows through the
dialysate lines to which a sensor module is connected. pH measurements may be taken by
using the pH sensor module directly from a container using the dip configuration. For water
purity measurements, a water sample is removed from the water purification system via a valve
and then tested using an appropriate sampling method. The 90XL pressure sensor module can
be used to verify the accuracy of arterial and venous monitors, measure negative pressure and
differential pressure of the delivery system fluid.
In-Line method using adapters
(Condo/temp, Pressure)
Dip sample method for pH
measurement
Sample tray and syringe for
conductivity measurement
