Dependency On Air Pressure - Dräger Vapor 2000 Technical Documentation Manual

3.4

Dependency on air pressure

The anaesthetic partial pressure delivered by the Vapor 2000 (see "Calibration" on page 5)
is virtually independent of the air pressure. Weather-related fluctuations are therefore
negligible. Altitude-related pressure changes between 700 and 1100 hPa, too, result in
minor deviations within the specified accuracy range (see technical specifications in
Instructions for Use). Consequently the physiological effect – the anaesthesia depth –
of a specific vaporizer setting is also independent of the air pressure.
When measuring the delivered concentration of the Vapor 2000 in partial pressure
(e.g. Dräger-IRIS or PM 8030/8035), no dependency on the ambient pressure occurs.
However, on measuring devices which give indications in percent by volume (e.g. Dräger-
PM 8020 or PM 8050) the measured values change with the air pressure. The measured
values increase when the air pressure falls below 1013 hPa.
Conversion formula:
Measured value [vol.%] . Air pressure [hPa]
Concentration [% partial pressure] = -------------------------------------------------------------------------------------------------
1013 hPa
Example:
At 4% partial pressure at an altitude of 1000 metres, 4.5 vol.% is displayed at 900 hPa (at
2000 metres 5.1 vol.% at 795 hPa).
Dependency of the boiling point of the anaesthetic on the air pressure (see "Boiling point of
anaesthetic" on page 6).
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5327.400 Vapor 2000 05/99 Function Description