Datex-Ohmeda S/5 B-GAS, Technical Reference Manual

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Datex-Ohmeda S/5 Anesthesia Monitor
Document No. 800 1005-1
22
2.2.7 PVX board
When Patient Spirometry is used, special sensors, D-lite or Pedi-lite, replaces the normal airway
adapter in the patient circuit. The spirometry tubing is attached to the two connectors on the sensor
and on the module front panel.
NOTE: Overpressure or negative pressure of more than 300 cmH
2
O to the flow and volume tubing
should never be applied.
The board is intended to perform the following tasks
•
Measure the pressures in airways and the speed of breathing flow.
•
Calculate tidal volume, minute volume, compliance and other useful information on patient
lungs.
Pressure transducers
There are two pressure transducers on the PVX board for airway pressure measuring purposes.
The breathing flow of a patient passing through D-lite adapter creates pressure difference. This
pressure difference is measured by pressure transducer, B1. Overpressure and negative pressure
in airways are measured by another pressure transducer B2.
NOTE: Never apply DIFFERENTIAL pressure higher than 25 cmH
2
O to the spirometry tubing. Make
sure that both spirometry tubes are always connected.
Temperature compensation
Temperature is measured by B1. This signal is used only for temperature compensation of the
pressure transducer B1 on the PVX board.
Data processing
After the multiplexer, the signals, PRESS, FLOW0, FLOW1, and TEMP are A/D converted for data
processing.
External communication
Communication between the PVX board and the Gas mother board is established in serial form,
using the serial channel (pins 10 and 11) of CPU on the PVX board.