ABGs

Question 1

Normal pH

Answer 1

7.35-7.45

Question 2

What does <7.35 pH indicate?

Answer 2

Acidosis (more H+ ions)

Question 3

What does >7.45 pH indicate?

Answer 3

Alkalosis (less H+ ions)

Question 4

What does PaO2 show?

Answer 4

• Partial pressure of O2 dissolved in plasma (3-5% of total oxygen content of arterial blood)
• tells us how well oxygen is moving from alveoli into the blood

Question 5

Normal PaO2 value

Answer 5

80-100 mmHg

Question 6

PaO2 indicating hypoxemia

Answer 6

<60 mmHg

Question 7

What does PaCO2 show us?

Answer 7

• Partial pressure of CO2 dissolved in plasma (5% of total CO2 content in arterial blood)
  *Measure of carbonic acid
  *Direct reflection of alveolar ventilation (how well the pt is ventilating, NOT oxygenation)

Question 8

Normal PaCO2 range

Answer 8

35-45 mmHg

Question 9

What does a PaCO2 <35 indicate?

Answer 9

Hyperventilation (blowing off too much CO2 = alkalosis)

Question 10

What does a PaCO2 >45 indicate?

Answer 10

Hypoventilation (CO2 buildup = **Respiratory acidosis)

Question 11

Causes of respiratory acidosis

Answer 11

1. CNS depression
2. Impaired neuromuscular function
3. Chest wall trauma
4. Large pneumo or Hemothorax
5. Airway disease or obstruction
6. Overdose (causing CNS depression)
7. Electrolyte imbalances - low phosphate, low potassium

Question 12

Manifestations of respiratory acidosis

Answer 12

1. CNS depression (lethargy, dizziness, mental cloudiness, HA, coma) *Remember acid is a depressant
2. Depression of myocardial contractility
3. V fib
4. Increased RR
5. Decreased affinity of Hg for O2 (Hgb wont pick up as much O2 now)

Question 13

Treatment for respiratory acidosis

Answer 13

1. Increase alveolar ventilation
   - TCDB/incentive spirometer
   - Suction
   - Mechanical ventilation
2. Correct the cause
3. Administer O2

Question 14

What does a PaCO2 <35mmHg indicate?

Answer 14

Respiratory Alkalosis (alveolar hyperventilation)

Question 15

Causes of respiratory alkalosis

Answer 15

1. Hypoxemia (too much compensation)
2. Artificial ventilation (over compensation)
3. Stress
4. Anxiety
5. Fear

Question 16

Respiratory alkalosis manifestations

Answer 16

CNS excitability (tingling, twitching, tremors, seizures)
Arrhythmias (premature beats & tachys)
Decreased ventilation (trying to compensate)
Increased affinity of Hg for O2 (hgb doesn’t drop O2 off to cells as well)

Question 17

Treatment for respiratory alkalosis

Answer 17

1. Decrease alveolar ventilation
2. Correct the cause

Question 18

What does HCO3 measure?

Answer 18

Metabolic base (which is regulated by the kidneys)

Question 19

Normal HCO3 range

Answer 19

22-28 mEq/L

Question 20

What does an HCO3 <22 indicate?

Answer 20

Metabolic acidosis (base deficit)

Question 21

What does an HCO3 >28 mEq/L indicate?

Answer 21

Metabolic Alkalosis (Base excess)

Question 22

Causes of metabolic acidosis

Answer 22

1. Increased production of acids (ex: DKA)
2. Reduced excretion of acids (Renal Failure)
3. Excessive loss of base (diarrhea)

Question 23

Manifestations of metabolic acidosis

Answer 23

1. HA
2. Confusion
3. Drowsiness
4. N/V
5. Hyperventilation

Question 24

Treatment of metabolic acidosis

Answer 24

1. Correct the cause
2. If severe, administer bicarbonate (pH <7)

Question 25

Causes of metabolic alkalosis

Answer 25

1. Loss of chloride (vomiting, NG suction, diuresis)
2. Chronic respiratory acidosis (conserving bicarbonate to compensate)
3. Base administration (too much)

Question 26

Manifestations of metabolic alkalosis

Answer 26

1. Numbness
2. Tingling
3. Dizziness
4. Carpopedal spasm (contracture of hand)
5. Decreased RR & depth (compensating to help kidneys)

Question 27

Treatment for metabolic alkalosis

Answer 27

1. Administer chloride (NS + extra potassium chloride)
2. Correct cause

Question 28

What does SaO2 show?

Answer 28

Degree to which Hg molecules are saturated with O2

Question 29

Normal SaO2 level

Answer 29

> or= 95%

Question 30

What does an SaO2 <90% indicate?

Answer 30

Hypoxemia

Question 31

How does the respiratory system compensate?

Answer 31

Acts in minutes to hours
Controls CO2 concentrations in ECF by changing rate and depth of respiration

Question 32

How does the renal system compensate?

Answer 32

Acts in hours to days
Increases or decreases HCO3 in ECF