ABG

Question 1

ABG’s Provide information on:

Answer 1

• Acid-base status of blood
• O2 & CO2 levels
• Ventilation

Question 2

pH Values

Answer 2

Range: 7.35-7.45
< 7.35 = Acidosis
Greater than 7.45 = Alkalosis

Question 3

PaCO2 Value

Answer 3

Range 35-45 mm Hg
Greater than 45 mm Hg = Acidosis (hypoventilation)
<35 mm Hg = Alkalosis (hyperventilation)

Question 4

PaO2 Value

Answer 4

80-100 mm Hg

Question 5

HCO3- Value

Answer 5

Range 22-27
<22 = Acidosis
Greater than 27 = Alkalosis

Question 6

What is respiratory acidosis caused by?

Answer 6

Hypoventilation

Question 7

Respiratory Alkalosis is caused by what?

Answer 7

Hyperventilation

Question 8

What is metabolic acidosis caused by?

Answer 8

Kidney Disease

Question 9

What is metabolic alkalosis caused by?

Answer 9

• Excessive Vomiting
• Loss of K+

Question 10

What are the three ways the body compensates for imbalances?

Answer 10

1. Buffer in body fluids
2. Respiratory system (Hyper/Hypo)
3. Kidneys

Question 11

6 Steps for ABG Interpretation

Answer 11

1. Is the pH normal?
2. Is the PaCO2 normal?
3. Is the HCO3 normal?
4. Match the pH status with PaCO2 or HCO3 (respiratory or metabolic cause)
5. Does the other (PaCO2 or HCO3) go in the opposite direction (Compensated/Uncompensated)
6. Are the PaO2 and the O2 Sat Normal? (>80 Normal; < 80 Hypoxemia)

Question 12

Match the PaCO2 or HCO3 to pH

Answer 12

Match (link) the pH (acidic or alkalotic) with the Pa CO2 or HCO3 that is acidic or alkalotic

• If pH is acidotic (<7.35) and Pa CO2 is acidotic (Greater than 45) then it is due to respiratory; respiratory acidosis
  OR
• If pH is acidotic (<7.35) and HCO3 is acidotic (<22) then it is due to metabolic; metabolic acidosis
• If pH is alkalotic (Greater than 7.45) and PaCO2 is alkalotic (<35) then it is respiratory; respiratory alkalosis OR
• If pH is alkalotic (Greater than 7.45) and HCO3 is alkalotic (Greater than 27) then it is metabolic; metabolic alkalosis

Question 13

Does PaCO2 or HCO3 go in the opposite direction of pH?

Answer 13

• Identify the respiratory or metabolic variable that did not match the pH (Pa CO2 or HCO3)
• If Pa CO2 or HCO3 goes in opposite direction from the pH there is compensation

Example:
pH = acidotic (<7.35)
Pa CO2 = acidotic (Greater than 45)
HCO3 = alkalotic not normal (Greater than 27)
Pa CO2 matches pH = respiratory acidosis
HCO3 opposite of pH
Compensation by metabolic system

Question 14

PaO2 and O2 Sat

Answer 14

PaO2
* Less than 80 (normal 80-100 mm Hg) – evidence of hypoxemia

O2 Sat
* O2 Sat should be less than 95% if PaO2 less than 80
* O2 Sat of 95-100% = PaO2 80-100 mmHg

Question 15

Hb and Hematocrit Values

Answer 15

Hb (transport O2)
* Men: 14-18 g/dL
* Women: 12-16 g/dL

Hematocrit (Ratio of volume in blood to RBC)
* Males: 42-52%
* Females: 37-48%

Hematocrit is often 3 times the Hb

H & H stands for Hb and Hematocrit

Question 16

Low Hb and Hematocrit levels result in:

Answer 16

Hb:
* < 8 = most likely no exercise but in some cases yes
* 8-10 = gentle exercise
* Greater than 10 = no restrictions
* Low Hgb - anemia, reduced exercise tolerance, significant fatigue and tachycardia

Hematocrit:
* SOB
* Dyspnea
* Tachycardia
* Fatigue
* Muscle cramping
* O2 Sat reading is hard to get

Question 17

Respiratory compensation for a metabolic disorder takes ____

Answer 17

minutes to hours

Due to the lungs being able to adjust

Question 18

Metabolic compensation for a respiratory disorder take ____

Answer 18

days