Arterial blood gases

Question 1

What is arterial blood gas analysis

Answer 1

Refers to the measurement of pH and the partial pressure of oxygen and CO2 in arterial blood

Question 2

What do ABGs help us assess?

Answer 2

effectiveness of gas exchange by providing measurements of the partial pressures of O2 and CO2

Question 3

what is paCO2 controlled by

Answer 3

ventillation

Question 4

what does pO2 measure

Answer 4

only free unbound O2 molecules

Question 5

What does the amount of O2 in the blood depend on

Answer 5

• Hb concentration: the capacity to carry

- sO 2:

Question 6

What is SO2

Answer 6

saturation of Hb with O2 - how much of the carrying capacity is being used

Question 7

PO2 is the driving force for…

Answer 7

saturating Hb with O2

Question 8

What dictates PaO

Answer 8

1. Alveolar ventilation
2. Ventilation/perfusion
3. FiO2

Question 9

When and why do you analyze arterial blood gases

Answer 9

1. Establish a diagnosis
2. To assess illness severity
3. To guide and monitor treatment

Question 10

What are normal ranges for pH

Answer 10

7.35-7.45

Question 11

what are normal ranges for PaCO2

Answer 11

35-45 mmHg

Question 12

What are normal ranges of HCO3

Answer 12

22-28 mEq/l

Question 13

what is the order of analysis for uncompensated ABG

Answer 13

Analyze pH
Analyze PaCo2
Analyze HCO3-

Question 14

If you have a change in only PaCo2 what does this indicate?

Answer 14

Primary disorder is respiratory

Question 15

What does a change in only HCO3- indicate

Answer 15

primary disorder is metabolic

Question 16

If both PaCo2 and HCO3 are off what does this mean?

Answer 16

compensated

Question 17

If only one of PaCo2 and HCO3 is off what does this mean?

Answer 17

uncompensated

Question 18

What is the time period for respiratory compensation? for renal compensation?

Answer 18

minutes to hours

1-5 days

Question 19

what are mixed disorders

Answer 19

when more than one primary acid-base disorder is occurring at the same time

Question 20

What are some causes of metabolic acidosis

Answer 20

• Ketoacidosis
• Poisoning
• Renal failure

Question 21

What are some causes of metabolic alkalosis

Answer 21

• Sodium base overload
• potassium depletion
• Vomiting
• Coshing’s syndrome
• Conns syndrome
• Nasogastric suction
• Some medications

Question 22

What are some causes of respiratory acidosis

Answer 22

• CO2 retention secondary to hypoventilation

- COPD, flail chest injury, neuromuscular disorders, sleep apnea

Question 23

What are some causes of respiratory alkalosis

Answer 23

• Secondary to alveolar hyperventilation

- pain, anxiety, fever, breathlessness, hypoxia

Question 24

Do PTs primarily help with respiratory or metabolic conditions

Answer 24

respiratory

Question 25

5 causes of impaired oxygenation

Answer 25

• Decrease inspired oxygen
• alveolar hypoventilation
• Diffusion impairment
• Shunt
• Ventilation/perfusion mismatch

Question 26

What is the major mechanism for hypoxemia

Answer 26

hypoventilation

Question 27

If hypoventilation is causing hypoxemia, PaO2 should decrease ___ for every ___ in PaCO2

Answer 27

1mmHg

1mmHg increase

Question 28

Hypoventilation leads to _____

Answer 28

respiratory acidosis

Question 29

hyperventilation leads to ____

Answer 29

respiratory alkalosis