System Processing Description
ARGUS VCM
100
50
0
50
100
S
atu
ra
tio
n
(%
)
PO
2
(mmHg)
pH
Temperature
PCO2
2,3-DPG
Fetal Hb
pH
Temperature
PCO2
2,3-DPG
Oxyhemoglobin Dissociation Curve
Functional versus Fractional Saturation
This monitor measures functional saturation — oxygenated hemoglobin expressed as a
percentage of the hemoglobin that can transport oxygen. It does not detect significant
amounts of dysfunctional hemoglobin, such as carboxyhemoglobin or methemoglobin.
In contrast, hemoximeters such as the IL482 report fractional saturation — oxygenated
hemoglobin expressed as a percentage of all measured hemoglobin, including measured
dysfunctional hemoglobin. To compare functional saturation measurements to those
from an instrument that measures fractional saturation, fractional measurements must
be converted as follows:
functional saturation = fractional saturation
100 – (%carboxyhemo %methemoglobin)
× 100
ARGUS VCM
Service Manual 69
