ABG interpretations

Question 1

Shift to the left

Answer 1

Increasing Hbg affinity for oxygen

Question 2

Shift to the right

Answer 2

Decreasing Hgb affinity for oxygen

Question 3

Carboxyhemoglobin

Answer 3

• hgb has as 200-250x greater affinity for CO2 than O2
• Shift to the left
• cherry red lips

Question 4

Methomeglobin

Answer 4

• Oxidized hgb molecules
• shift to the left
• reddish brown blood, cyanosis (blue people)
  Management: methylene blue

Question 5

Fetal hemolgobin

Answer 5

• Two beta chains are absent and two gamma chains are present
• Shift to the left
• Spontaneous resolution

Question 6

Hypoxemia Hypoxia

Answer 6

• pO2 supply is deficient

- ex. pneumothorax, high altitudes

Question 7

Anemic Hypoxia

Answer 7

• Decreased oxygen carrying capacity deficient hbg
• decreased hbg = anemia
• decreased ability to bind = carboxyhemoglobin and methemoglobinemia

Question 8

Circulatory Hypoxia

Answer 8

• Stagnant (cardiogenic)

- arterial-venous shunting ( septic shock)

Question 9

Histotoxic Hypoxia

Answer 9

• Inability of the tissue to use oxygen, cell death

- cyanide poisoning - sodium nitroprusside toxicity

Question 10

pH

Answer 10

< 7.35 = acidosis

>7.45 = alkalosis

Question 11

pCO2

Answer 11

<35 = low
>45 = high

Question 12

HCO3

Answer 12

<22 = low
>26 = high

Question 13

R.O.M.E

Answer 13

• Respiratory (PCO2) = opposite direction than pH

- Metabolic (HCO3) = equal/same direction to pH

Question 14

Respiratory acidosis

Answer 14

Chlorine inhalation injury, asthma, pneumonia

Question 15

Respiratory alkalosis

Answer 15

Hyperventilation, anxiety

Question 16

Metabolic acidosis

Answer 16

Acid gain, anion gap-shift in electrolytes (Na+, Cl-, HCO3-)

Question 17

MUD PILE CATS

Answer 17

M: menthol, metformin
U: Uremia
D: DKA
P: paraldehyde, pregnancy
I: isoniazid and iron
L: lactic acidosis
E: ethylene glycol
C: carbamazepine
A: alcoholic ketoacidosis
T: Theophylline
S: salicylates, starvation ketoacidosis

Question 18

Metabolic Alkalosis

Answer 18

Acid loss, Bicarb gain, tx: saline responsiveness