Week 2 ABGs ✅

Question 1

When do you do an ABG?

Answer 1

Respiratory disorders e.g. asthma, COPD
Resuscitation
Sepsis
Metabolic acidosis

Question 2

Why is lactate produced?

Answer 2

Anaerobic respiration

Question 3

What is met-Hb?

Answer 3

Methoglobin

Question 4

What is co-Hb?

Answer 4

Carboxyhemoglobin

Question 5

What is acid?

Answer 5

concentration of hydrogen ions

Question 6

How do you do an ABG?

Answer 6

Wash hands
Get sharps bin
LA might be appropriate
Allen test
Take blood from radial artery

Question 7

How do you do an Allen test?

Answer 7

Occlude radial artery

Question 8

What are the by-products of metabolism?

Answer 8

H+
H20
CO2

Question 9

How is acid disposed of?

Answer 9

Gaseous exchange in lungs
Carbonic anhydrase converts CO2 and H2O into H2CO3

Question 10

How is CO2 and H2O converted into H2CO3?

Answer 10

Carbonic anhydrase

Question 11

What is the buffer system?

Answer 11

H+ + HCO3- <-> H2CO3 <-> H2O + CO2

Question 12

How long does it take for kidneys to compensate?

Answer 12

6-12 hours

Question 13

What is respiratory compensation?

Answer 13

Breathe out more or less CO2

Question 14

How do you diagnose respiratory acidosis/alkalosis? (not aemia!)

Answer 14

CO2 below or above normal

Question 15

How do you diagnosis metabolic acidosis/alkalosis? (not aemia!)

Answer 15

HCO3 below or above normal

Question 16

Why might a pH still be normal in an acid-base balance?

Answer 16

Not an acid base problem!
Chronic COPD - chronic metabolic compensation
Both acid AND alkaline problem

Question 17

What does SBE stand for and what does it mean?

Answer 17

Standard base excess

Measure of other buffers - correlates with HCO3

Question 18

What do you need to consider when interpreting ABGs?

Answer 18

History - risk and signs/symptoms

Data - pH, O2, CO2, HCO3, single or multiple acid-base disturbance?

Integration - do the suspicions agree with the data?

Question 19

How do you work out the expected kPa from FiO2?

Answer 19

FiO2 - 10 = kPa