Edwards EV1000

Appendix B: Equations for Calculated
Patient Parameters
his section describes the equations used to calculate
continuous patient parameters displayed on the
EV1000 monitor.
 Patient parameters are calculated to more decimal
places than are displayed on the screen. For example, a
screen CO value of 2.4 may actually be a CO of 2.4492.
Consequently, attempts to verify the accuracy of the
monitor's display using the following equations may
produce results that are slightly different from the data
computed by the monitor.
 SI = Standard International Units
T
Table B-1 Cardiac Profile Equations
Parameter Description and Formula Units
BSA Body Surface Area (DuBois formula)
BSA = 71.84 x (WT
0.425
) x (HT
0.725
) / 10,000
where:
WT - Patient Weight, kg
HT - Patient Height, cm
m
2
CaO
2
Arterial Oxygen Content
CaO
2
= (0.0138 x HGB x SpO
2
) + (0.0031 x PaO2) (mL/dL)
CaO
2
= [0.0138 x (HGBSI x 1.611) x SpO
2
] + [0.0031 x (PaO
2
SI x7.5)] (mL/dL)
where:
HGB – Total Hemoglobin, g/dL
HGBSI – Total Hemoglobin, mmol/L
SpO
2
– Arterial O2 Saturation, %
PaO
2
– Partial Pressure of Arterial Oxygen, mmHg
PaO
2
SI – Partial Pressure of Arterial Oxygen, kPa
mL/dL
CvO
2
Venous Oxygen Content
CvO
2
= (0.0138 x HGB x SvO
2
) + (0.0031 x PvO
2
) (mL/dL)
CvO
2
= [0.0138 x (HGBSI x 1.611) x SvO
2
] + [0.0031 x (PvO
2
SI x7.5)] (mL/dL)
where:
HGB – Total Hemoglobin, g/dL
HGBSI – Total Hemoglobin, mmol/L
SvO
2
– Venous O
2
Saturation, %
PvO
2
– Partial Pressure of Venous Oxygen, mmHg
PvO
2
SI – Partial Pressure of Venous Oxygen, kPa
and PvO
2
is assumed to be 0
mL/dL
Ca-vO
2
Arteriovenous Oxygen Content Difference
Ca-vO
2
= CaO
2
- CvO
2
(mL/dL)
where:
CaO
2
– Arterial Oxygen Content (mL/dL)
CvO
2
– Venous Oxygen Content (mL/dL)
mL/dL