Cardinal Health Alaris 8000 Series, Directions For Use Manual

Page: 276 / 378

Principle of Operation (Continued)
4-32
General Information
Alaris
®
System Directions for Use
SpO
2
Modules Section
When saturation is calculated from a blood gas partial
pressure of oxygen (
PO
2
), the calculated value may differ from
the
S
p
O
2
measurement of the
S
p
O
2
Module, this usually
occurs because the calculated saturation was not
appropriately corrected for the effects of variables that shift the
relationship between
PO
2
and p
H
, temperature, the partial
pressure of carbon dioxide (
PCO
2
),
2,3-DPG
, and fetal
hemoglobin. To compare functional saturation measurements
to those from an instrument that measures fractional
saturation, fractional measurements must be converted as
follows:
Oxyhemoglobin Dissociation Curve
­
pH
Temperature
PCO
2,3-DPG
Fetal Hb
2
¯
¯
¯
­
­
pH
Temperature
PCO
2,3-DPG
2
¯
¯
¯
100
50
0
50 100
PO (mmHg)
2
Saturation
(%)
¬
®
8210 Series (Continued)
(8210)