GE HEALTHCARE E-PSMP, Technical Manual

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Module Frames and Modules
8 - 14
2062973-004
The factory calibration coefficients of the sensor are stored in an EEPROM memory on the
miniOM board. When the module starts up, the calibration coefficients are read to the module
CPU and then used for calculating the O2 concentration from the Oxygen raw data received
from the sensor.
1.3.5 MiniPVX measuring unit
NOTE: Never apply the overpressure or negative pressure of more than 300 cmH
2
O to the flow
and volume tubing. Differential pressure max 25 cmH
2
O is allowed on one port at a time e.g.
when connecting tubes.
When Patient Spirometry is used, a special sensor, D-lite, replaces the normal airway adapter
in the patient circuit. A double lumen tubing is attached to the two connectors on the adapter
and on the module front panel.
The Patient Spirometry provides patient respiration monitoring capabilities using the D-lite and
Pedi-lite flow sensors.
Figure 12 MiniPVX measuring unit
The measurement is based on measuring the kinetic gas pressure and is performed using the
Pitot effect. A pressure transducer is used to measuring the Pitot pressure. The signal is then
linearized and corrected according to the density of the gas. Speed of the flow is calculated
from the pressure and TV is integrated from it.
Patient Spirometry consists of airway connections, two pressure transducers, valves and
preamplifiers. The preamplifiers are connected to the A/D-converter on the module main CPU.
The patient’s breathing flow passing through the D-lite adapter creates a pressure difference.
This pressure difference is measured by a pressure transducer, B1. Overpressure and negative
pressure in airways are measured by another pressure transducer, B2.
1.3.6 Gas exchange
The gas exchange measurement uses the concentrations measured by the TPX measurement
unit and the O
2
measurement unit, in combination with the flow from the PVX measurement
unit. The gas exchange calculation is done by software.
NOTE: The gas exchange measurement in the E-sCAiOVX and E-sCOVX modules works
accurately only with 2-meter (7 ft) gas sampling lines.