Siemens Rapidlab 1200 - Patient Temperature Correction; Hemoglobin Oxygen Saturation; Oxygen Content

1-56 Rapidlab 1200 Operator’s Guide: System Overview and Intended Use
02087462 Rev. V
Patient Temperature Correction
The Rapidlab 1200 systems measurements and determinations are based on a standard
temperature of 37.0°C. During sample analysis, you can enter the actual patient
tempera
ture value, which enables the system to provide temperature-corrected results for
pH, pCO
2
, and pO
2
.
The system determines temperature-corrected result
s using the following correction
factors:
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pH correction = ΔpH / ΔT = –0.0147 + 0.0065(7.4–pH)
0.019
T
CO log
correction CO
2
2
=
Δ
Δ
=
p
p
2.30 O 10 9.72
0.071 O 10 5.49
T
CO log
correction CO
3.88
2
9–
3.88
2
–11
2
2
+××
+××
=
Δ
Δ
=
p
pp
p
Hemoglobin Oxygen Saturation
Hemoglobin oxygen saturation (sO
2
) is a ratio of the amount of hemoglobin bound to
oxygen to the total amount of hemoglobin able to bind oxygen.
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Hemoglobin oxygen
saturation, with oxygen content and oxygen capacity, is a useful parameter for determining
the amount of oxygen in the blood that is actually available to the tissues and for
determining the effectiveness of oxygen therapy.
Hemoglobin oxygen saturation, expressed as a percent,
is determined using the following
equation:
sO
2
= (100 x FO
2
Hb) / (FO
2
Hb + FHHb)
Oxygen Content
Oxygen content is the concentration of the total oxygen carried by the blood, including
oxygen bound to hemoglobin as well as oxygen dissolved in plasma and in the fluid within
red cells.
Clinically, dissolved oxygen is unimportant for most
situations. However, at very low
levels of hemoglobin or in patients receiving hyperbaric oxygen therapy, dissolved oxygen
may be a very significant contributor to oxygen content and thus to oxygen transport.
Oxygen content is determined, using CLSI recommendations, from the
following
relationship:
ctO
2
= (FO
2
Hb ×1.39 × ctHb + 0.00314 × pO
2
)
where ctHb is ex
pressed in g/dL and FO
2
Hb is decimal.
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