ABGs

Question 1

arterial blood gas values: (need to know)Normal values

Answer 1

pH: 7.35 – 7.45
PaCO2: 35 – 45 mmHg
HCO3: 22 – 26 mEq/l
PaO2: 80 – 100 mmHg

Question 2

Acid vs. base (acidotic vs. alkalotic)

Answer 2

pH 7.35 - 7.45 (7.4 middle)

PaCO2 45 -35 (40 middle)

HCO3 22 -26 (24 middle)

Acid to the left Base to the right

** notice that the numbers on PaCO2 values are opposite for this scale… the higher the carbon dioxide the more acidic **

Question 3

Respiratory acidosis:

Compensation:
Kidneys conserve HCO3 and secrete H+ into the urine

Causes:
Respiratory failure, infection, hypoventilation, too much medication, brain injury, lung disease

Answer 3

Hypoventilation - increased cO2 – increased carbonic acid
Carbonic acid dissociates into H+ ions – which decreases pH

Question 4

Respiratory alkalosis:

Answer 4

Hypoxemia from acute pulmonary disorders
Hyperventilation

Causes of respiratory alkalosis:
Primary cause is hypoxemia from acute pulmonary disorders
Anxiety, panic attack, acute condition causing hyperventilation

Hyperventilation “blows off” CO2, leading to a decreased carbonic acid concentrations and alkalosis

Question 5

Metabolic acidosis:

Excess carbonic acid production or base bicarbonate deficit caused by:
Ketoacidosis
Monitor for hyperglycemia

Lactic acid will promote oxygenation and perfusion to the tissues
Lactic acid accumulation (shock)

Kidney disease
Monitor kidney function

Bicarbonate loss
Monitor for diarrhea

Question 6

Metabolic alkalosis:

Base bicarbonate excess caused by:
Prolonged vomiting or gastric suction
Gain of HCO3

Compensatory mechanisms:
Renal secretion of HCO3
Decreased respiratory rate to increase plasma CO2 (limited)