Interfering Gases; Unit Conversions - GE Healthcare B30 User's Reference Manual

B30 Patient Monitor

Interfering gases

Non-disturbing gases are those with a maximum effect on the CO
effect is valid for specific concentrations shown in parentheses of the non-disturbing gas:
Ethanol C
Acetone (<0.1%)
Methane CH
Nitrogen N
water vapor
Dichlorofluoromethane (<1%)
Tetrafluoroethane (<1%)
Disturbing gases and their effect on the CO
listed reflect the effect of specific concentrations (shown in parentheses) of an individual
disturbing gas and should be combined when estimating the effect of gas mixtures:
Halothane (4%) increases < 0.3 vol%
Isoflurane (5%) increases < 0.4 vol%
Enflurane (5%) increases < 0.4 vol%
Desflurane (24%) increases < 1.2 vol%
Sevoflurane (6%) increases < 0.4 vol%
Helium (50%) decreases < 0.3 vol%
If O compensation is not activated: O
2
If O compensation is activated: O
2
If N O compensation is not activated: N
2
increases < 0.8 vol%
If N O compensation is activated: N
2

Unit conversions

Relationship between gas concentration and its partial pressure:
Reading in mmHg (dry gas) =
(ambient pressure in mmHg) x (gas concentration in%)
Reading in mmHg (water vapor saturated gas) =
(ambient pressure in mmHg - 47 mmHg) x gas concentration in%
Reading in kPa (dry gas) =
(ambient pressure in mmHg) x (gas concentration in%)
Reading in kPa (water vapor saturated gas) =
((ambient pressure in mmHg - 47mmHg) x (gas concentration in%)
NOTE: 47 mmHg is the partial pressure of the saturated water vapor at 37°C.
17-8
H OH (<0.3%)
2 5
(<0.2%)
4
2
100
100
750
750
reading at 5.0 vol-% CO
2
(40 to 95%) decreases < 0.3 vol%
2
(40 to 95%) error < 0.15 vol%
2
O (40%) increases < 0.4 vol%, N
2
O (40 to 80%) error < 0.3 vol%
2
reading < 0.2 vol%. The
2
are shown below. Errors
2
O (40 to 80%)
2