Blood Gases

Question 1

What is the Henderson-Hasselbalch equation used for?

Answer 1

To relate pH to bicarbonate and carbon dioxide levels

pH = pKa + log(HCO3-/PCO2)

Question 2

What is the bicarbonate/carbonic acid buffer system ratio?

Answer 2

20:1

This ratio is crucial for maintaining pH balance in the body.

Question 3

How do the lungs help regulate pH?

Answer 3

By removing CO2

Question 4

How do the kidneys regulate pH?

Answer 4

By reclaiming or excreting HCO3-

Question 5

What is the time frame for kidneys to fully respond to pH changes?

Answer 5

About 3 days

Question 6

What is the relationship between pH and bicarbonate?

Answer 6

Directly proportional

Question 7

What is the relationship between pH and hydrogen ions?

Answer 7

Inversely proportional

Question 8

What is the relationship between pCO2 and pH?

Answer 8

Inversely proportional

Question 9

What causes metabolic acidosis?

Answer 9

Decrease in pH and HCO3-

Question 10

What causes respiratory acidosis?

Answer 10

Decrease in pH with increased pCO2

Question 11

What causes metabolic alkalosis?

Answer 11

Increased pH and HCO3-

Question 12

What causes respiratory alkalosis?

Answer 12

Increased pH with decreased pCO2

Question 13

What is a mixed alkalosis scenario?

Answer 13

Increased pH, HCO3- with decreased pCO2

Question 14

What is a mixed acidosis scenario?

Answer 14

Decreased pH, HCO3- with increased pCO2

Question 15

What is the reference range for pH?

Answer 15

7.35-7.45

Question 16

What is the reference range for pCO2?

Answer 16

35-45 mmHg

Question 17

What is the reference range for HCO3-?

Answer 17

22-28 mmol/L

Question 18

What is the reference range for pO2?

Answer 18

85-105 mmHg

Question 19

What does a pH of 7.31 and HCO3 of 15 indicate?

Answer 19

Metabolic acidosis

Question 20

What is the compensation mechanism when PCO2 needs to come down to increase pH?

Answer 20

Respiratory compensation

Question 21

What indicates partial compensation?

Answer 21

If pH is <7.35 or >7.45 but other variable has moved to fix the problem

Question 22

What indicates full compensation?

Answer 22

If pH is back within reference range

Question 23

What is the first line of defense against acidosis?

Answer 23

Lungs

Question 24

What happens during hypoventilation?

Answer 24

Increased CO2

Question 25

What is the relationship between bicarbonate and CO2?

Answer 25

Bicarb = 1.1 less than CO2

Question 26

What is the best buffer in the body?

Answer 26

Bicarbonate

Question 27

What is the 'chloride shift'?

Answer 27

When bicarbonate leaves the cell, chloride enters | Maintains charge in RBC during exchange of gases.

Question 28

What does MUDPILES stand for in the context of acidosis causes? | DELETE

Answer 28

Uremia, DKA, Lactic acid

Question 29

What can cause high PCO2?

Answer 29

* COPD * Drugs (e.g., Morphine, Alcohol) * Metabolic alkalosis

Question 30

What can give us a high bicarbonate level?

Answer 30

* Too many antacids * Proton pump inhibitors * Excess loss from vomiting * Nasogastric suction

Question 31

What can cause low PCO2?

Answer 31

* Hysteria * Salicylates (Aspirin)

Question 32

What is the Clark electrode used for?

Answer 32

To measure pO2

Question 33

What is the specimen of choice for acid-base status involving pulmonary dysfunction in adults?

Answer 33

ABG

Question 34

What is the consequence of leaving a blood gas specimen exposed to air?

Answer 34

Increased PO2 and pH, decreased PCO2

Question 35

What happens to blood gas left in a tray for 2 hours at room temperature?

Answer 35

Decreased O2, increased PCO2, decreased pH

Question 36

What is the significance of the oxygen dissociation curve?

Answer 36

Shows how hemoglobin releases O2 based on pH, PCO2, temperature, and 2,3-DPG

Question 37

What is the range for fetal hemoglobin?

Answer 37

> 200

Question 38

What can cause severe diarrhea in terms of acid-base balance?

Answer 38

Loss of all base

Question 39

What is the anticoagulant of choice for blood gas analysis?

Answer 39

Lyophilized heparin

Question 40

What can be a source of error in blood gas analysis?

Answer 40

* Bubbles * Hemolysis * Improper collection