Blood Gases 1

Question 1

Arterial/venous blood gases/ Circuit arterial/venous blood gases are an invaluable tool in assessingthe following 3 things?

Answer 1

• ventilation
• acid-base balance
• oxygenation

Question 2

Arterial Blood Gas It is an invasive procedure, it helps to differentiate oxygen deficiencies from

Answer 2

primary ventilatory deficiencies from

primary metabolic acid-base abnormalities

Question 3

PaO2

Answer 3

partial pressure of oxygen dissolved in the plasma only. 90 - 100

Question 4

SaO2

Answer 4

measured degree to which oxygen is bound to hemoglobin.

> 95%

Question 5

PaCO2

Answer 5

-partial pressure of carbon dioxide dissolved in the plasma. - The rest is inside the red blood cells on a hemoglobin molecule 35 - 45

Question 6

HCO3

Answer 6

Bicarbonate buffer 24 + or - 2

Question 7

pH

Answer 7

Negative logarithm of the number of hydrogen ions (H+) in a solution, expressed as a number between 1 and 14 7.35 - 7.45

Question 8

BE

Answer 8

Base Excess (-2) - (+2)

Question 9

Acid/Base Relationship is critical for homeostasis, Significant deviations from normal pH ranges are

Answer 9

poorly tolerated and may be life threatening

Question 10

Acid/Base Relationship is Achieved by ?

Answer 10

Respiratory and Renal systems

Question 11

There are two buffers that work in pairs that are linked to the Respiratory and Renal compensatory system

Answer 11

H2CO3 Carbonic acid NaHCO3 base bicarbonate

Question 12

Respiratory Component

Answer 12

H2CO3 Carbonic acid CO2 + H2O = H2CO3

Question 13

Approximately 98% normal metabolites are in the form of ?

Answer 13

CO2

Question 14

Metabolic Component Function of the kidneys

Answer 14

Na HCO3 base bicarbonate

Question 15

carbonic anhydrase

Answer 15

an enzyme that accelerates hydration/dehydration CO2 in renal epithelial cells

Question 16

active exchange of Na+ for H+ happens between the ____ ___ and the _____ ______.

Answer 16

tubularcells and glomerular filtrate

Question 17

6 Normal ABG values

Answer 17

pH 7.35 – 7.45 PCO2 35 – 45 mmHg PO2 80 – 100 mmHg HCO3 22 – 26 mmol/L BE -2 - +2 SaO2 >95%

Question 18

pH < 7.35 PCO2 > 45 HCO3 < 22

Answer 18

Acidosis

Question 19

pH > 7.45 PCO2 < 35 HCO3 > 26

Answer 19

Alkalosis

Question 20

Think of CO2 as an acid, failure of the lungs to exhale adequate CO2 results in what ?

Answer 20

Respiratory Acidosis

Question 21

pH < 7.35 PCO2 > 45

Answer 21

Respiratory Acidosis

Question 22

CO2 + H2CO3 =

Answer 22

decrease in pH

Question 23

5 Non CPB Causes of Respiratory Acidosis

Answer 23

• emphysema - drug overdose - narcosis - respiratory arrest - airway obstruction

Question 24

2 Causes of Respiratory Acidosis while on CPB?

Answer 24

• Gas flow rate - Sweep rate

Question 25

5 Non CPB Causes of Metabolic Acidosis

Answer 25

- renal failure - diabetic ketoacidosis - lactic acidosis - excessive diarrhea - cardiac arrest

Question 26

1 Cause of Metabolic Acidosis while on CPB?

Answer 26

Poor perfusion

Question 27

too much CO2 exhaled (hyperventilation) causes what ?

Answer 27

Respiratory Alkalosis

Question 28

pH \> 7.45 PCO2 \< 35

Answer 28

Respiratory Alkalosis

Question 29

What are 6 Causes of Respiratory Alkalosis

Answer 29

- hyperventilation - panic d/o - pain - pregnancy - acute anemia - salicylate overdose

Question 30

pH \> 7.45 HCO3 \> 26

Answer 30

Metabolic Alkalosis

Question 31

3 Causes of Metabolic Alkalosis Non CPB ?

Answer 31

• Increase loss of acid from stomach or kidney • hypokalemia • excessive alkali intake Tums overdose

Question 32

1 cause of Metabolic Alkalosis while on CPB?

Answer 32

Too much Bicarb

Question 33

Step 1 in ABG interpretation, Examine the PaO2 & SaO2 to determine ?

Answer 33

oxygenation status

Question 34

Low PaO2 (\<80 mmHg) & SaO2 means what?

Answer 34

hypoxia

Question 35

NL/elevated oxygen means

Answer 35

adequate oxygenation

Question 36

Step 2 in ABG interpretation, evaluate the \_\_\_?

Answer 36

PH

Question 37

Step 3 in ABG interpretation, evaluate whether its a ___ or ___ component?

Answer 37

Respiratory / Metabolic

Question 38

Step 4 in ABG interpretation, determine if there is a ?

Answer 38

compensatory mechanism working to try to correct the pH.

Question 39

What is the main functional substance of RBCs.

Answer 39

- Hemoglobin, consists of 4 heme molecules. responsible for blood’s red color - Contain iron in the Ferrous state

Question 40

Male normal hgb ? hct ?

Answer 40

13-16 gm/dl 42-50%

Question 41

Female normal hgb ? hct ?

Answer 41

12-15 gm/dl 40 -48%

Question 42

Hemoglobin makes up _____ of the dry weight of RBC’s

Answer 42

95 %

Question 43

destruction of red blood cell membrane.

Answer 43

Hemolysis

Question 44

When the RBC membrane ruptures Hb is released into the plasma these subunits can block the ____ of ____ \_\_ \_\_\_\_causing impairment/failure of these organs..

Answer 44

micro vasculature of kidneys and lungs

Question 45

3 Primary forms of CO2 Transport

Answer 45

- 5% dissolved in plasma -15% combine w/ Hb (Carbamino hemoglobin -80% enters the RBC and converted to H2CO3

Question 46

80% of CO2 enters the RBC and is converted to?

Answer 46

H2CO3

Question 47

15% of CO2 combines with _____ as it enters the blood stream?

Answer 47

Hb (Carbamino hemoglobin)

Question 48

5% of CO2 is dissolved in ___ as it crosses the capillary wall?

Answer 48

Plasma

Question 49

The “Haldane Effect”

Answer 49

Increase in CO2 Displaces oxygen from the hemoglobin which causes an increase in O2 delivery.

Question 50

The reverse “Haldane Effect”

Answer 50

binding of O2 to hemoglobin tends to displace CO2 from the blood

Question 51

combination of O2 and HB in the lungs causes

Answer 51

Hb to become a stronger acid.

Question 52

combination of O2 and HB in the lungs causes Hb to become a stronger acid, this displaces CO2 from the blood and into the aveoli in 2 ways.

Answer 52

- Acidic Hb is less likely to form carbaminoHb - Acidic Hb releases excess H+ ions, these bind to bicarb, this dissociates to CO2 & H2O

Question 53

2 Compensatory Mechanisms

Answer 53

- Respiratory Compensation - Renal compensation

Question 54

Pink Urine ?

Answer 54

Concern for breaking of the RBC.

Question 55

Normal value of pO2 on CPB ?

Answer 55

150 - 250 mmHg

Question 56

pO2 value on CPB is 100 mmHg. What will your actions as a perfusionist be ?

Answer 56

Increase my FiO2 to reach pO2 values between 150 - 250 mmHg.

Question 57

A Base Excess \> -2 indicates what ? How would you the perfusionist treat this on CPB?

Answer 57

Metabolic Acidosis. Treat by increasing pump flow.

Question 58

A pH of 7.3 & a pCO2 of 52 mmHg on CPB means what? How would you the perfusionist correct this ?

Answer 58

Respiratory Acidosis Correct by turning up the Sweep.