GE HEALTHCARE E-PSMP, Technical Manual

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Module Frames and Modules
5 - 2
2062973-004
Figure 2 Temperature measurement
(1) Adapter cable for temperature probes
(2) Reusable
temperature probe
(3) Adapter cable for disposable temperature probe
(4) Disposable
temperature probe
Equipment safety symbols
1.2 Measurement principle
1.2.1 Invasive blood pressure
To measure invasive blood pressure, a catheter is inserted into an artery or vein. The invasive
pressure setup, consisting of connecting tubing, pressure transducer, an intravenous bag of
normal saline all connected together by stopcocks, is attached to the catheter. The transducer
is placed at the same level with the heart, and is electrically zeroed.
The transducer is a piezo-resistive device that converts the pressure signal to a voltage. The
monitor interprets the voltage signal so that pressure data and pressure waveforms can be
displayed.
1.2.2 Temperature
The temperature is measured by a probe whose resistance varies when the temperature
changes, called Negative Temperature Coefficient (NTC) resistor.
The resistance can be measured by two complementary methods:
•
Applying a constant voltage across the resistor and measuring the current that flows
through it.
•
Applying a constant current to flow through the resistor and measuring the voltage that
is generated across it.
This symbol on the module refers to defibrillator precautions. To ensure
protection against the effects of cardiac defibrillator discharge, always use the
recommended cables and leadwires only (see the supplemental information
manual). Using other cables or leadwires may result in damage to the
equipment and compromise patient and/or user safety.