Roche cobas b 123 - A;Ao; Avdo

Roche Diagnostics
Instructions for Use · Version 13.0 103
cobas b 123 POC system 4 Theoretical foundations
Parameters and calculations
a/AO
2
Arterial alveolar oxygen partial pressure ratio.
[5]
Unit: [%]
Equation 4-22
PaO
2
= PO
2
u a/AO
2
t
(p. 107) for patient temperatures other than 37 °C.
avDO
2
Arterial venous oxygen tension ratio.
[1]
Unit: [vol%]
Equation 4-23
Calculated ctO
2
(a) and ctO
2
(v) according to the calculation for ctO
2
for arterial and
venous blood.
u ctO
2
(p. 101).
Calculating avDO
2
requires the following conditions:
o Same patient numbers for both measurements
o 2 consecutive measurements
o Sample type is arterial and mixed venous blood
RI
The respiratory index is calculated as the ratio of the alveolar-arterial oxygen tension
gradient to the arterial oxygen tension.
[6]
Unit: [%]
Equation 4-24
q
RI values are only provided for “arterial” or “capillary” blood types.
PaO
2
= PO
2
u RI
t
(p. 107) for patient temperatures other than 37 °C.
100
AO
aO
a/AO
2
2
2
⋅=
P
P
avDO
2
ctO
2
a() ctO
2
v()–=
100
)
(
⋅
−
=
2
22
aO
aOAO
RI
P
PP