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23.6 Ventilation Calculations
The monitor provides the ventilation calculation function. The monitor can save the results of up to 10
calculations, which are displayed in groups.
23.6.1 Performing Ventilation Calculations
To perform ventilation calculations, follow this procedure:
1. Access ventilation calculation by either of the following ways:
◆ Select the Calculations quick key → Ventilation tab.
◆ Select the Main Menu quick key → from the Calculations column select Ventilation.
2. Enter the known values. For a patient who is being monitored, the currently measured values are automat-
ically taken. If the anesthesia machine or ventilator is connected, measured values for ventilation calcula-
tion are also automatically taken.
3. Select Calculate.
The calculated value greater than the normal upper limit is indicated by an up arrow “↑”. The calculated
value lower than the normal lower limit is indicated by a down arrow “↓”.
On the Ventilation page, you can also perform the following operations:
■ Select Pressure Unit. Then corresponding parameter values will be automatically converted and updated
accordingly.
■ Select Range to show the normal range of each parameter.
23.6.2 Input Parameters for Ventilation Calculations
23.6.3 Calculated Parameters and Formulas for Ventilation Calculations
Input Parameter Label Unit
percentage fraction of inspired oxygen FiO
2
%
respiration rate RR rpm
partial pressure of mixed expiratory CO2 PeCO
2
mmHg, kPa
partial pressure of carbon dioxide in the arteries PaCO
2
mmHg, kPa
partial pressure of oxygen in the arteries PaO
2
mmHg, kPa
tidal volume TV ml
respiratory quotient RQ None
atmospheric pressure ATMP mmHg, kPa
Calculated Parameters Label Unit Formula
partial pressure of oxygen
in the alveoli
PAO
2
mmHg, kPa PAO
2
(mmHg) = [ATMP (mmHg) - 47 mmHg] ×
FiO
2
(%)/100 - PaCO
2
(mmHg) × [FiO
2
(%)/100 + (1
- FiO
2
(%)/100)/RQ]
alveolar-arterial oxygen
difference
AaDO
2
mmHg, kPa AaDO
2
(mmHg) = PAO
2
(mmHg) - PaO
2
(mmHg)
oxygenation ratio Pa/FiO
2
mmHg, kPa Pa/FiO
2
(mmHg) = 100 × PaO
2
(mmHg)/FiO
2
(%)
arterial to alveolar oxygen
ratio
a/AO
2
%
a/AO
2
(%) = 100 × PaO
2
(mmHg)/PAO
2
(mmHg)
minute volume MV L/min MV (L/min) = [TV (ml) × RR (rpm)]/1000
volume of physiological
dead space
Vd
ml
Vd (ml) = TV (ml) × [1 - PeCO
2
(mmHg)/PaCO
2
(mmHg)]