NOVA BIOMEDICAL Stat Profile PRIME Instructions For Use Manual page 99

P50 or PO (0.5)*
2
The P50 is defined as the PO
hemoglobin is 50% saturated with oxygen at pH 7.4, 37°C,
and 40 mm Hg PCO
80%.
=PO
P50
(uncorrected)
For measured SO
is as follows:
Where z = tanh(0.5343
ln(SO %/(100-SO
2
P50 =26.902
(uncorrected)
z - 2.87)) Equation 31
The corrected equation is as follows:
log P50
(corrected)
0.05 (log PCO /40) – 0.0131(T – 37)
2
* The equations are from Reference 4.
of a sample at which the
2
for SO % values between 40% and
2 2
/(SO %/(100-SO
2 2
% between 80 and 96.9%, the equation
2
x); x = ln(0.133
*
%))-1.875
2
exp(1.121
*
= log P50
(uncorrected)
Appendix B
0.37
%)) Equation 30
2
PO /7); y =
* 2
(y-x-3.5z)/(1.87
*
+ 0.43 (pH – 7.4) –
Equation 32
2
z +
*
B-13