CURRENT ABG INTERPRETATION EXAM QUESTIONS AND ANSWERS 2025
The following blood gas measurements
determines how well a patients lungs are PaCO2
being ventilated.
PvO2: Normal value 35 - 45 mmHg. A de-
creased PvO2 indicates inadequate oxy-
genation of the tissues most commonly
caused by a decreased cardiac output.
As cardiac output drops, blood flow to
the tissues slows while tissue oxygen up-
The following blood gas measurements take remains at the same rate. Therefore,
determines the level of tissue oxygena- some tissues take more oxygen from the
tion. blood than normal, which deprives other
tissues of the normal amount of oxygen.
When the blood returns from the body
to the pulmonary artery, it contains less
oxygen that it should and is reflected by
a drop in PvO2.
PAO2 = (PB - 47)FiO2 - (PaCO2 * 1.25)
A patient using an aerosol mask set at A-a
40% oxygen Shortcut for PAO2 = (7 * O2%) - (PaCO2
pH 7.42, PaCO2 36, PaO2 122, HCO3 + 10)
What is the A-a gradient? PB = 747 (700 * 0.40) - (36 + 10) = 234
A-a = 234 - 122 = 112
The following conditions shifts the HbO2 Hypercapnia
dissociation curve to the right?
Patient on 2 lpm via NC has the interpret
the following ABG results Acute respiratory alkalosis
pH 7.51, PaCO2 27, PaO2 62, HCO3 23
The RCP has received an order to obtain
ABG levels from a patient, but an Allen Check collateral circulation in the left
test indicates collateral circulation is not wrist.
present in the right wrist. At this time the
RCP would
Interpret ABG
Uncompensated (acute) metabolic aci-
pH 7.21
dosis with normal oxygenation
PaCO2 43
1/3
The following blood gas measurements
determines how well a patients lungs are PaCO2
being ventilated.
PvO2: Normal value 35 - 45 mmHg. A de-
creased PvO2 indicates inadequate oxy-
genation of the tissues most commonly
caused by a decreased cardiac output.
As cardiac output drops, blood flow to
the tissues slows while tissue oxygen up-
The following blood gas measurements take remains at the same rate. Therefore,
determines the level of tissue oxygena- some tissues take more oxygen from the
tion. blood than normal, which deprives other
tissues of the normal amount of oxygen.
When the blood returns from the body
to the pulmonary artery, it contains less
oxygen that it should and is reflected by
a drop in PvO2.
PAO2 = (PB - 47)FiO2 - (PaCO2 * 1.25)
A patient using an aerosol mask set at A-a
40% oxygen Shortcut for PAO2 = (7 * O2%) - (PaCO2
pH 7.42, PaCO2 36, PaO2 122, HCO3 + 10)
What is the A-a gradient? PB = 747 (700 * 0.40) - (36 + 10) = 234
A-a = 234 - 122 = 112
The following conditions shifts the HbO2 Hypercapnia
dissociation curve to the right?
Patient on 2 lpm via NC has the interpret
the following ABG results Acute respiratory alkalosis
pH 7.51, PaCO2 27, PaO2 62, HCO3 23
The RCP has received an order to obtain
ABG levels from a patient, but an Allen Check collateral circulation in the left
test indicates collateral circulation is not wrist.
present in the right wrist. At this time the
RCP would
Interpret ABG
Uncompensated (acute) metabolic aci-
pH 7.21
dosis with normal oxygenation
PaCO2 43
1/3
