Arterial Blood Gases (ABGs)

Question 1

What are the normal values for pH, CO2, and HCO3 ?

Answer 1

• pH: 7.35-7.45
• CO2: 35-45
• HCO3: 22-26

Question 2

How does hydrogen ions affect pH ?

Answer 2

• acidic: more hydrogen ions lowers pH
• basic: less hydrogen ions raises pH

Question 3

What is a buffer ?

Answer 3

chemical substances that release or accept hydrogen ions
- “sponges” to correct imbalances

Question 4

How does the respiratory system affect acid base balance ?

Answer 4

eliminate or retain CO2
- hypoventilation increases CO2
- hyperventilation decreases CO2
- response is quick but effect is temporary

Question 5

How does the renal system affect acid base balance ?

Answer 5

eliminate or retain H+/HCO3
- low pH causes reabsorption of HCO3 and excretion of H+
- high pH causes excretion of HCO3 and save H+
- slow response (takes 2-3 days to fully respond)

Question 6

How is FiO2 affected by O2 ?

Answer 6

fraction of inspired O2 goes up with supplemental O2

Question 7

What is PaO2 ?

Answer 7

partial pressure of O2 in arterial blood
- O2 dissolved in blood plasma

Question 8

Is CO2 a acid or base ?

Answer 8

acid

Question 9

Is HCO3 a acid or base ?

Answer 9

base

Question 10

What happens if PO2 is higher then 100 ?

Answer 10

the pt is on too much supplemental O2

Question 11

What are some causes of respiratory acidosis ?

Answer 11

• COPD
• reduced function of respiratory center
  
  • hypoventilation
  • oversedation
  • drug OD
  • neurological disorders
  • inadequate mechanical ventilation

Question 12

What are some S&S of respiratory acidosis ?

Answer 12

• decreased RR
• HA
• cyanosis

Question 13

What is the treatment for respiratory acidosis ?

Answer 13

improve alveolar ventilation
- assess RR
- correct cause
- increase ventilation & gas exchange

Question 14

What are the causes of respiratory alkalosis ?

Answer 14

hyperventilation
- anxiety
- pain
- respiratory rate setting on ventilator too high
- fever
- respiratory stimulant drugs

Question 15

What are the S&S of respiratory alkalosis ?

Answer 15

• neuromuscular issues
• irritability
• vertigo
• dizziness

Question 16

What is the treatment for respiratory alkalosis ?

Answer 16

• breathe into a paper bag (slows breathing and allows to get back some of that lost CO2)
• calm client
• treat fever
• lower ventilator rate

Question 17

What are some causes of metabolic acidosis ?

Answer 17

• GI loss of bicarb from intestine
• diarrhea, intestinal fistula
• DKA
• starvation, malnutrition, dehydration
• lactic acidosis due to anaerobic metabolism from shock
• renal failure

Question 18

What are some S&S of metabolic acidosis ?

Answer 18

• bradycardia
• malaise
• hyperpnea but no dyspnea (kussmaul respirations from DKA)

Question 19

What is the treatment for metabolic acidosis ?

Answer 19

• correct underlying cause (give insulin for DKA)
• may treat with sodium bicarbonate
• dialysis if they already get it (for renal failure pt’s)
• IV fluids

Question 20

What are some causes of metabolic alkalosis ?

Answer 20

• excess bicarb
• vomiting or NGT suctioning
• diuretic therapy (lasix)
• loss of hydrogen, potassium, chloride
• antacid administration
• excessive ingestion of licorice

Question 21

What are some S&S of metabolic alkalosis ?

Answer 21

• tachycardia
• numbness
• tingling
• hand tremors

Question 22

What is the treatment for metabolic alkalosis ?

Answer 22

• antiemetics for nausea
• treat symptoms and correct cause
• stop antacid
• replace fluid and electrolytes

Question 23

What is considered partially compensated ?

Answer 23

when all 3 values are abnormal

Question 24

What is considered fully compensated ?

Answer 24

if pH is normal
- but both the CO2 and HCO3 are abnormal

Question 25

What is considered uncompensated ?

Answer 25

if pH is abnormal and only one other component (CO2 or HCO3) is abnormal