2. Introduction
• Arterial blood gas (ABG) is a test that
measures the acid-base balance,
oxygenation status, and respiratory
function of a patient's blood. It is a
crucial diagnostic tool used in the
management of critically ill patients,
particularly those with respiratory or
metabolic disorders.
3. Procedure
• ABG analysis involves obtaining
a small sample of arterial blood
usually from the radial artery in
the wrist. The site is cleaned with
an antiseptic solution, and a
needle is inserted into the artery.
Blood is then drawn into a
syringe, and the needle is
removed. Pressure is applied to
the puncture site to prevent
bleeding.
4. Interpretation
• ABG results provide information
about the patient's acid-base
balance, oxygenation, and
respiratory function. The test
measures the partial pressure of
oxygen (PaO2), partial pressure of
carbon dioxide (PaCO2), pH,
bicarbonate (HCO3-), and oxygen
saturation (SaO2).
5. pH
• pH measures the acidity or alkalinity
of the blood. The normal range is
7.35-7.45. A pH below 7.35 is acidic,
while a pH above 7.45 is alkaline.
6. PaO2
• PaO2 measures the amount of
oxygen dissolved in the arterial
blood. The normal range is 80-100
mmHg. A PaO2 below 80 mmHg
indicates hypoxemia, or low blood
oxygen levels.
7. PaCO2
• PaCO2 measures the amount of
carbon dioxide dissolved in the
arterial blood. The normal range is
35-45 mmHg. A PaCO2 above 45
mmHg indicates hypercapnia, or high
blood carbon dioxide levels.
8. HCO3
• HCO3- measures the amount of
bicarbonate in the blood, which is an
important buffer that helps to
maintain the acid-base balance. The
normal range is 22-28 mEq/L. A
HCO3- level below 22 mEq/L
indicates metabolic acidosis, while a
level above 28 mEq/L indicates
metabolic alkalosis.
9. SaO2
• SaO2 measures the percentage of
hemoglobin molecules that are
bound to oxygen. The normal range
is 95-100%. A SaO2 below 95%
indicates hypoxemia.
10. Conclusion
• In conclusion, ABG is a vital tool in
the management of critically ill
patients. It provides valuable
information about the patient's acid-
base balance, oxygenation, and
respiratory function. Interpreting the
ABG results accurately is crucial in
providing the appropriate treatment
to the patient.
