Abg Physiology And Practice Questions

Front 1

What is happening?
PaO2 = 88
PaCO2 = 40
pH = 7.34
HCO3- (serum CO2) = 19

Back 1

First, look at pH (7.34) - normal is 7.35 to 7.45. pH is low
Next, look at bicarb (19) - normal is 22 to 26. Bicarb is low
Metabolic acidosis

Front 2

What is happening?
PaO2 = 85
PaCO2 = 32
pH = 7.55
HCO3 (serum) CO2 = 25

Back 2

First, look at pH (7.55) - normal is 7.35 to 7.45. pH is high - alkalosis
Next, look at bicard (25) - normal is 22 to 26. Bicarb is normal.
Look

Front 3

What is a substance which gives up H+?

Back 3

acid

Front 4

What is a substance which accepts H+?

Back 4

base

Front 5

What are substances which can function as an acid or a base?

Back 5

amphoteric substance (amino acids & proteins)

Front 6

What is a reflection of the free H+ concentration, is inversely related to the concentration of free H+, and has a negative logarithm in relation to H+ (if it changes 1 unit, H+ changes 10x - 10 fold)

Back 6

pH

Front 7

What are some examples of chemical buffers?

Back 7

Phosphate, plasma proteins, bicarbonate H2CO3 - HCO3, hemoglobin

Front 8

Carbon dioxide is transported as:

Back 8

- dissolved CO2
- hemoglobin (Hgb)
- bicarbonate (HCO3-)

Front 9

Normal pH balances:
PaO2
PaCO2
pH
Serum CO2 (HCO3)

Back 9

- 80 to 100
- 35 to 45
- 7.35 to 7.45
- 22 to 26
respiratory parameter = PaCO2 (an acid substance & changed by the lungs
metabolic parameter = Serum CO2 (an alkaline substance & changed by the kidney

Front 10

Interpretation of Acid-Base?

Back 10

1. What is pH? Acid or alkaline?
2. Is the respiratory parameter
- Normal?
- Adding acid?
- Taking away acid?
3. Is the metabolic parameter
- Normal?
- Adding alkaline?
- Taking away alkaline?
4. Which one agrees with the pH? (This is the system that is causing the pH shift)
5. Is one of the parameters opposite of the pH? (This is the system that is compensating for the pH)

Front 11

PaO2 = 58
PaCO2 = 49
pH = 7.32
Serum CO2 = 30

Back 11

1. pH = 7.32 - low
2. PaO2 = 58 - low
3. PaCO2 = 49 - high
4. O2 agrees with the pH - respiratory acidosis
5. CO2 is opposite of pH, and so is attempting to compensate. renal composition

Front 12

PaO2 = 98
PaCO2 = 26
pH = 7.55
Serum CO2 = 24.5

Back 12

Respiratory alkalosis

Front 13

Carbonic acid (H2CO3) is a ___ acid. It is a ___ acid that readily becomes __ and __. The __ can be blown off through the respiratory system.

Back 13

volatile
weak
CO2
water
CO2

Front 14

Body acids are volatile (___ acids) or nonvolatile (___ acids)

Back 14

respiratory
metabolic

Front 15

The metabolic acids are ___ acids and are eliminated through the renal tubules with ___.

Back 15

nonvolatile
bicarb (HCO3)

Front 16

The H2CO3 (carbonic acid)/HCO3 (bicarb) buffering pair operates in the ___ and the ___. At ideal pH (7.4), the ratio of carbonic acid to bicarb is ___.

Back 16

lungs
kidneys
1:20

Front 17

T/F:
The less carbon dioxide there is in the arterial blood, the more carbonic acid will be formed.

Back 17

False. The amount of carbonic acid formed is directly proportional to the amount of CO2 in the blood.

Front 18

How can the lungs decrease the amount of carbonic acid?

Back 18

By blowing off CO2.

Front 19

T/F:
The dissociation of carbon dioxide creates CO2 and carbonic acid.

Back 19

False. The dissociation of carbonic acid creates CO2 and water.

Front 20

T/F:
When buffering, the kidneys act quickly and crudely, and the lungs work more slowly but can fine tune the ration more precisely.

Back 20

False. The renal system works more slowly in order to fine tune the ration between bicarb and carbonic acid (20:1)

Front 21

With ___ the body is returning the ratio of bicarb and carbonic (20:1), but the actual values of both are not normal. ___ occurs when the values return to normal

Back 21

Compensation
Correction

Front 22

Renal buffering of hydrogen ions (H+) requires the use of __ and __ to form carbonic acid. The enzyme __ then dissociates it to __ and __.
Where does the bicarb go?
Where does the H+ go?

Back 22

CO2 and H2O
carbonic anhydrase
H+
HCO3-
Reabsorbed by kidney tubules
Binds with phosphate or ammonia and is excreted in urine

Front 23

When H+ binds with phosphate it is __ __, and cannot diffuse back into the renal tubule and so is excreted.

Back 23

lipid insoluble

Front 24

Why can proteins work to buffer the H+ ion?

Back 24

Because they are negatively charged.

Front 25

T/F:
Hgb in venous blood is a better buffer than Hgb loaded with O2 in arterial blood

Back 25

True

Front 26

What does K+ do when the body is in a state of acidosis or alkalosis?

Back 26

It will shift its ICF/ECF position to work as an ionic buffer to H+. In acidosis, it will leave the ICF to change places with H+, and vice versa during alkalosis.
The problem arises with large movements of this ionic buffer.

Front 27

How does acidosis occur?

Back 27

systemic increase in H+, or loss of base

Front 28

T/F:
Hypoxemia causes acidosis slowly; renal failure causes it quickly.

Back 28

False. Hypoxemia causes it quickly; renal failure slowly

Front 29

What happens in metabolic acidosis?

Back 29

noncarbonic acids increase (lactic acid) or bicarb (base) is lost and cannot be regenerated by the kidney.

Front 30

Buffering systems and hyperventilation attempt to __ H+ and __ pH.

Back 30

lower
increase

Front 31

Anion gap analysis helps to distinguish between different types of __ __.

Back 31

metabolic acidosis

Front 32

An elevated anion gap is characteristic of acidosis associated with what?

Back 32

anions other than chloride (Cl-). These include proteins (albumin), phosphate, sulfate, lactate, and are usually not measured in lab values.

Front 33

Metabolic alkalosis is usually caused by excessive loss of __.

Back 33

metabolic acids (vomiting, suctioning). Gastric juice pH is very acidic (pH = 1-3).

Front 34

T/F:
When acid is lost to vomiting, renal compensation is very effective.

Back 34

False. It's not very effective because the volume depletion and loss of electrolytes (Na+, K+, H+, Cl-) causes kidney to reabsorb Na+ and Bicarb. Reabsorbing Bicarb makes it difficult to correct alkalosis.

Front 35

What should you do in order to make renal compensation more effective when acid is lost to vomiting?

Back 35

Increase volume and replace chloride anion in order to decrease renal stimulus to reabsorb Na, which lets bicarb be wasted in the urine.

Front 36

T/F:
As opposed to metabolic alkalosis, in acute respiratory acidosis renal compensation is highly effective.

Back 36

False - renal compensation is too slow to compensate for acute respiratory acidosis. However, it can be effective in uncomplicated, chronic respiratory acidosis.

Front 37

What happens in respiratory acidosis?

Back 37

alveolar hypoventilation, CO2 retained, hypercapnea. When CO2 retained, carbonic acid (H2CO3) is formed increasing retention of H+ ions, causing acidosis.

Front 38

What happens in respiratory alkalosis?

Back 38

alveolar hyperventilation and decreased CO2 (hypocapnea).

Front 39

Increased ventilation in respiratory alkalosis is stimulated by __, which results from __.

Back 39

hypoxemia
pulmonary disease, heart failure, fever, high altitude

Front 40

Chronic respiratory alkalosis leads to

Back 40

kidneys decrease H+ excretion and bicarb absorption