Blood Gas Analysis

Question 1

T/F: H+ is constantly being produced by metabolism.

Answer 1

True

Question 2

What organs are involved in acid-base homeostasis?

Answer 2

Lungs, Kidney, Liver, GIT

Question 3

What are the chemical buffers in the body?

Answer 3

Extracellular: HCO3-
Intracellular: Phosphate, proteins (slower acting)

Question 4

How long does renal compensation take?

Answer 4

Hours to days

Question 5

How long does respiratory compensation take?

Answer 5

Minutes (increase or decrease RR)

Question 6

What are measured in Blood gas analysis?

Answer 6

• pH
• PaCO2
• PaO2

Question 7

What are calculated in blood gas analysis?

Answer 7

• HCO3-
• BE
• O2 content (CaO2)

Question 8

What is assessed for respiratory component?

Answer 8

PaCO2

Question 9

What is assessed for metabolic component?

Answer 9

BE or HCO3

Question 10

Normal pH

Answer 10

7.35-7.45

Question 11

Normal HCO3-

Answer 11

24+/-4 mEq/L

Question 12

Normal PaCO2

Answer 12

35-45 mmHg

Question 13

Herbivores produce more……

Answer 13

HCO3-

Question 14

Normal Cat values

Answer 14

HCO3- ~20mEq

PsCO2 ~30mmHg

Question 15

Base Excess

Answer 15

Refers to an excess or deficit in the amount of base present in the blood

The differene of HCO3- from normal value if PaCO2 and temp were normalized

Question 16

Positive Base excess

Answer 16

Metabolic alkalosis

Question 17

Negative Base excess

Answer 17

Metabolic acidosis

aka base deficit

Question 18

Anion Gap

Answer 18

The amount of positive and negative ions should be equal, the difference is represented in unmeasured ions

Question 19

Main positive ions

Answer 19

Na and K

Question 20

Main negative ions

Answer 20

Cl and HCO3

Question 21

Normal Anion Gap

Answer 21

16+/-4 mEq/L

Question 22

What causes elevated AG?

Answer 22

Metabolic acidosis (KLUE)

Ketoacidosis
Lactic acidosis
Uremia
Ethylene glycol or other toxins/drugs

Question 23

Metabolic acidosis with a normal AG?

Answer 23

May be due to Cl retention or HCO3 excretion

Diarrhea or renal disease

Question 24

Total CO2 is a measurement of?

Answer 24

HCO3- and dissolved CO2

Question 25

Is TCO2 an accurate measurement of HCO3?

Answer 25

Yes, dissolved CO2 is only a small amount

Question 26

T/F: Results of blood gas should be interpreted with physical exam, lab work, etc.

Answer 26

True

Question 27

PaCO2 is ____ related to CO2 production and _____ related to CO2 elimination

Answer 27

Directly; indirectly

Question 28

Results of PaCO2

Answer 28

1. Lower the PaO2 2. Lower the pH 3. Reflect respiratory acidosis 4. Reflect respiratory compensation for metabolic alkalosis

Question 29

Does PaO2 reflect O2 content?

Answer 29

No

Question 30

Is PaO2 or PAO2 lower?

Answer 30

PaO2 is always lower

Question 31

Reason for high A-a difference

Answer 31

V/Q mismatch Right to left shunt Diffusion impairment (not vet med)

Question 32

Reasons for V/Q mismatch

Answer 32

Atelectasis | Lung diseases

Question 33

PaO2/FiO2 ratio

Answer 33

Serves same purpose as A-a gradient but easier to interpret

Question 34

Normal PaO2/FiO2 ratio

Answer 34

>500mmHg

Question 35

Hypoxemia

Answer 35

Insufficient oxygenation of arterial blood SpO2

Question 36

5 Causes of Hypoxemia

Answer 36

1. Low FiO2 2. Hypoventilation 3. Diffusion impairment 4. V/Q mismatch 5. Right to left shunt

Question 37

A-a PO2 has been used to distinguish what?

Answer 37

Lung disease from hypoventilation as a cause of hypoxemia

Question 38

Under anesthesia, what is A-a PO2 difference used to diagnose?

Answer 38

V/Q mismatch resulting from pulmonary atelectasis

Question 39

Hypoxemia with normar PaO2

Answer 39

Anemia or pathological Hb

Question 40

Hypoxia

Answer 40

Insufficient oxygenation of the tissues

Question 41

Causes of hypoxia

Answer 41

1. Hypoxemia 2. Insufficient tissue perfusion 3. Insufficient uptake of O2 by cells