Siemens Rapidlab 1200 Operator's Manual page 56

1-36
The levels of HCO
in blood. This relationship is best described through the Henderson-Hasselbalch equation:
=
pH
Substituting HCO
reads as follows:
=
pH
Taking the equation further, pH is seen as being proportional to the acid-base relationship:
α
pH
Although other acids and bases are present in the blood, the H
sensitive and dynamic and typically reflects other acid-base changes.
When the measurement of the partial pressure of carbon dioxide (pCO
combined with the measured pH, the values can be incorporated into the
Henderson-Hasselbalch equation to determine HCO
value is proportional to the content of dissolved CO
used along with pH not only to calculate HCO
acid-base abnormalities.
This analyte reflects the overall respiratory status. Thus high pCO
suppression or failure, whereas low pCO
stem from hypoxia, anxiety, fever, cerebral disease, cirrhosis, or excessive mechanical
ventilation). Extreme abnormalities of pCO
pathophysiologic state that must be corrected promptly.
Together, pH and pCO
function. An increase in the pCO
acidosis, a condition in which CO
and an increase in pH indicates respiratory alkalosis, a condition in which the lungs are
expiring too much CO
02087462 Rev. V
Rapidlab 1200 Operator's Guide: System Overview and Intended Use
–
, H CO , and dissolved CO
3 2 3
base
+
pK log
acid
–
as the base and dissolved CO
3
−
HCO
+ 3
pK log
+
CO H CO
2 2
−
HCO
3
H CO
2 3
provide a more definitive diagnostic tool in assessing respiratory
2
relative to the amount produced.
2
play a major role in maintaining the pH
2
and H
2
3
–
and ctCO
3
/HCO
2
–
but also to aid in the differentiation of
3
indicates hyperventilation (which in turn may
2
reflect a potentially life-threatening
2
6,7
value and a decrease in pH indicates respiratory
2
is retained by the lungs. A decrease in the pCO
2
CO as the acid, the equation
2 3
–
CO /HCO relationship is
2 3 3
) in the blood is
2
. Because the pCO
2
–
, the value for pCO
3
indicates respiratory
2
2
can be
2
value
2