Acid-Basics 4: Arterial Blood Gas (ABG) analysis (AS lecture)

Question 1

what is an arterial blood gas analysis?

Answer 1

• analysis of gases in a sample of blood

Question 2

Define the term Base excess in arterial blood gas analysis

Answer 2

the theorectical amount of acid needed to bring blood back to normal pH

Question 3

what does a high base excess mean and what does a low base excess mean in terms of the condition of the body

Answer 3

high:
- alkalotic condition

low:
- acidotic condition

Question 4

what is the difference between compensation and correction in acid-base disturbances

Answer 4

• compensation referes to the physiological response to acid-base imbalances
• correction is when the pH is brought back into normal ranges

Question 5

what is the normal pH range of the arterial blood

Answer 5

7.35-7.45

Question 6

what is the normal H+ concentration at pH 7.4

Answer 6

40nmol/L (4x 10^-8 mol/L)

Question 7

what is the normal value for PaCO2 in the arteries in both mmHg and kPa

Answer 7

• 35-45 mmHg
• 4.6 - 6 kPa

Question 8

what is the normal concentration of HCO3- in the arteries

Answer 8

22-26 mmol/L

Question 9

Go through last 3 lecture slides and answer the 3 questions on ABG analysis