Datex-Ohmeda S/5 monitors
Document No. 800 1009-1
18
Figure 10
OM measuring unit
2.2.4
PVX measuring unit
NOTE: Never apply overpressure or negative pressure of more than 300 cmH
2
O to the flow and
volume tubing. Differential pressure max 25 cmH2O 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 11
PVX 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 measure 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.
The Patient Spirometry consists of airway connections, two pressure transducers, valves and
preamplifiers. The preamplifiers are connected to the A/D-converter on module main CPU.
The breathing flow of a patient passing through the D-lite adapter creates a pressure difference.
This pressure difference is measured by pressure transducer, B1. Overpressure and negative
pressure in airways are measured by another pressure transducer B2.
