Pulmonary Function Tests

Question 1

Normal blood pH range

Answer 1

7.35-7.45

Question 2

Normal PaCO2 range

Answer 2

35-45 mmHg

Question 3

Normal HCO3 range

Answer 3

22-26 mEq/L

Question 4

What is compensation

Answer 4

if the pH imbalance is caused by the respiratory system (CO2) , the renal system (HCO3) will try to compensate and vice versa

Question 5

What is metabolic acidosis

Answer 5

ph decreases
pCO2 stays the same
HCO3 decreases

Question 6

What is metabolic alkalosis

Answer 6

ph increase
pCO2 stays the same
HCO3 increases

Question 7

What is respiratory acidosis

Answer 7

ph decreases
pCO2 increases
HCO3 stays the same

Question 8

What is respiratory alkalosis

Answer 8

ph increases
pCO2 decreases
HCO3 stays the same

Question 9

6 steps to analyze Arterial blood gases

Answer 9

1. is the pH normal
2. is the CO2 normal
3. Is the HCO3 normal
4. Match the CO2 or the HCO3 with the pH
5. Does the CO2 or the HCO3 go the opposite direction of the pH
6. are the pO2 and the O2 saturation normal

Question 10

What do these ABGs indicate?

pH 7.16 CO2 49 HCO3 38

Answer 10

Respiratory Acidosis

Question 11

What do these ABGs indicate?

pH 7.58 CO2 54 HCO3 28

Answer 11

Metabolic Alkalosis

Question 12

What does an FEV1/FVC reading 10 below predicted indicate?

Answer 12

Obstruction

Question 13

What does a decreased FEV1 indicate

Answer 13

Obstruction (particularly the severity of the obstruction)

Question 14

What does a decreased FVC indicate

Answer 14

Restriction

Question 15

What does GOLD define COPD as

Answer 15

FEV1/FVC ratio < 70% after treatment

Question 16

What test do you do prior to drawing an ABG and what artery are you taking the blood from usually?

Answer 16

Allen’s test to make sure there is good collateral flow to the hand, and the radial artery

Question 17

Define acidosis in relationship to pathological changes occurring in the body

Answer 17

Acidosis is when the pH decreases <7.35, this is more common because carbon dioxide is dissolved in the blood as carbonic acid (weak acid). This occurs when there is poor pulmonary ventilation, CO2 levels rise, which leads to rise in carbonic acid and decreased pH.

Question 18

Define alkalosis in relationship to the pathological changes occurring in the body.

Answer 18

Alkalosis is increased pH >7.45= too little CO2 in blood, due to hyperventilation or excessive breaths given via a mechanical ventilator in a cricical care setting. Try to reduce the number of breaths taken to normalize pH. Respiratory compensation pathway will try to compensate for this in 2-4 hours, if it can’t help enough the metabolic pathway compensates.

Question 19

ABG findings in metabolic acidosis

Answer 19

 pH↓, pCO2 same, bicarb ↓

Question 20

ABG finding in metabolic alkalosis

Answer 20

pH↑, pCO2 same, bicarb ↑

Question 21

ABG findings in respiratory acidosis

Answer 21

pH ↓, pCO2↑, bicarb same

Question 22

ABG findings in respiratory akalosis

Answer 22

pH ↑, pCO2 ↓, bicarb same