Chapter 11

Front 1

diffusion

Back 1

Gas movement between the lungs and tissues occurs via simple diffusion

Front 2

Identify where the highest/lowest PO2 & PCO2 are found.

Back 2

Highest PO2 in air, lowest in cells. Highest PCO2 in cells, lowest in air.

Front 3

Define PAO2

Back 3

Alveolar partial pressure of oxygen

Front 4

Calculate PAO2

Back 4

PAO2=FIO2x (PB-47) - PACO2

Front 5

List normal values for PO2 and PCO2 of the venous blood returning to the lungs from the right side of the heart.

Back 5

PO2=100 mmHg
PCO2=40 mmHg

Front 6

State how many times faster CO2 diffuses across the avleolar capillary than does O2?

Back 6

CO2 diffuses 20 times faster than O2

Front 7

Describe P50

Back 7

P50=partial pressure of O2 at which the Hb is 50% saturated, standardized to a pH of 7.40

Front 8

pH saturation value for a normal P50

Back 8

7.40

Front 9

PO2 saturation value for a normal P50

Back 9

26.6 mmHg

Front 10

Hb saturation value for a normal P50

Back 10

50%

Front 11

Define the Haldane effect

Back 11

the more oxygen that is bound to a hemoglobin molecule, the less CO2 will bind to that molecule

Front 12

Identify a normal A-a gradient P(A-a) O2

Back 12

Normal A-a gradient is 5-10 mmHg on room air, and no more than 65mmHg when 100% is breathed

Front 13

Describe what it means if the A-a gradient is elevated.

Back 13

if the gradient is high, it indicates a large difference between the alveolar and arterial PO2 values.

Front 14

A-a gradient formula

Back 14

P(A-a) O2 = PAO2-PaO2

Front 15

Describe the Bohr Effect

Back 15

pH alters the bonding of O2 to hemoglobin - this is known as the Bohr effect

Front 16

Conditions/factors that cause a decrease in Hb affinity for O2

Back 16

Acute acidosis
High CO2
Increased temperature
High levels of 2,3-DPG
Abnormal hemoglobin

Front 17

Conditions/factors that cause an increase in Hb affinity for O2

Back 17

Acute alkalosis
Decreased PCO2
Decreased temperature
Low levels of 2,3-DPG
Carboxyhemoglobin
Methemoglobin
Abnormal hemoglobin

Front 18

Shift in the oxyhemoglobin (O2Hb) dissociation curve to the Right.

Back 18

Decreased affinity for O2
More tissue oxygenation
Increased H+ (lower pH)
Increased PCO2
Increased Temp
Increased 2,3-DPG

Front 19

Shift in the oxyhemoglobin (O2Hb) dissociation curve to the Left.

Back 19

Increased affinity for O2
Less tissue oxygenation
Decreased H+ (higher pH)
Decreased PCO2
Decreased temp
Decreased 2,3-DPG

Front 20

What is the formula to calculate the total oxygen content of arterial and venous blood?

Back 20

CaO2=(PaO2 x 0.003) + (1.34 x Hb x SaO2)
CvO2=(PvO2 x 0.003) + (1.34 x Hb x SvO2)

Front 21

Normal value for CaO2

Back 21

16-20 ml/dl

Front 22

Normal value for CvO2

Back 22

14-15 ml/dl

Front 23

Normal value PaO2

Back 23

>80 torr

Front 24

Normal value PvO2

Back 24

37-43 torr

Front 25

Normal value SaO2

Back 25

>95%

Front 26

Normal value SvO2

Back 26

70-76%

Front 27

Normal value Hb

Back 27

12-16 grams/100 ml blood or grams percent g%

Front 28

PaO2 is related to what form of oxygen?

Back 28

Physically dissolved oxygen

Front 29

What is the formula for Dissolved O2?

Back 29

ml/dl=PO2x0.003

Front 30

Identify the 2 components responsible for carrying oxygen in the blood.

Back 30

dissolved in the plasma & erythrocyte intracellular fluid - the majority of O2 is carried in a reversible chemical combination with hemoglobin (Hb) inside the RBC.

Front 31

Calculate the saturation of the arterial blood (SaO2) using the appropriate formula.

Back 31

SaO2=[HbO2/total Hb] x 100

Front 32

Identify the hemoglobin saturation of the arterial blood (SaO2) that correlates with a PO2 of 65 mmHg

Back 32

SaO2 90%

Front 33

Calculate cardiac output using the Fick Formula

Back 33

Qt=VO2/[C(a-v) O2x10]

Front 34

Compare Carbon Monoxide's (CO) affinity for hemoglobin to that of Oxygen's

Back 34

hemoglobin's affinity for carbon monoxide is more than 200 times greater than it is for oxygen

Front 35

Define PaCO2

Back 35

Dissolved plasma carbon dioxide

Front 36

What does decreased PaCO2 mean?

Back 36

it means the patient is having more ventilation

Front 37

What does an increase in PaCO2 mean?

Back 37

it means the patient is having less ventilation

Front 38

Explain the major ways that CO2 is transported in the blood - give the percentages for each for

Back 38

Dissolved in physical solution 8%, chemically combined with protein 12%, ionized as bicarbonate 80%

Front 39

Calculate oxygen delivery (DO2)

Back 39

DO2= C.O. x (CaO2 x 10)
C.O. = cardiac output

Front 40

Define the term Hypoxia

Back 40

when oxygen delivery falls short of cellular needs, hypoxia occurs.

Front 41

When the pH is increased (hydrogen ion concentration (H+) is decreased), in which direction will the HbO2 Dissociation curve shift?

Back 41

To the "left"

Front 42

In what direction does the oxygen (HbO2) Dissociation Curve shift when the pH is decreased?

Back 42

To the "right"

Front 43

The Ventilation/Perfusion ratio (V/Q) represents:

Back 43

Changes in alveolar ventilation (VA) and pulmonary capillary blood flow (Qc)

Front 44

In which direction will the O2 Dissociation Curve shift, due to an increase in body temperature?

Back 44

To the right

Front 45

100% O2 may not be sufficient to achieve satisfactory arterial oxygen content under what condition?

Back 45

Hypoxemia due to physiological shunting.

Front 46

The impact of changes in blood pH on hemoglobin's affinity for oxygen is called the

Back 46

Bohr effect

Front 47

How would you describe hypoxia?

Back 47

tissue O2 delivery is inadequate to meet cellular needs

Front 48

What is the overall main goal of acid-base homeostasis?

Back 48

Maintain a normal blood pH

Front 49

With respect to the excretion of H+ and reabsorption, how will the kidneys respond if the blood PaCO2 is high?

Back 49

Excrete H+ and retain HCO3-

Front 50

What is the most common cause of hyperventilation in patients with respiratory disease?

Back 50

low arterial PaO2 (hypoxemia)

Front 51

An increase in body temperature will shift the oxygen dissociation curve in what direction?

Back 51

Right

Front 52

The _____Effect alters the position of the HbO2 Dissociation curve.

Back 52

Bohr

Front 53

In healthy young adults, what is considered a normal of PAO2-PaO2 gradient (A-a Gradient)?

Back 53

5 to 10 mmHg

Front 54

What contains the highest level of PCO2?

Back 54

Cells

Front 55

The normal total oxygen content of the blood is approximately____________

Back 55

19.5 mEq/L

Front 56

What is the normal CaO2-CvO2 (arteriovenous oxygen content difference) in a healthy adult at rest?

Back 56

5 mL/dL

Front 57

Which of the following approximate a normal P50?

Back 57

26.6

Front 58

A PaO2 of 100 mmHg is normally associated with a hemoglobin saturation (SaO2) of _______.

Back 58

97%

Front 59

What would be the approximate hemoglobin saturation (SaO2) associated with a PaO2 of 65 mmHg?

Back 59

90%

Front 60

Where is the lowest PO2 normally found?

Back 60

Cells

Front 61

The majority of oxygen (O2) is carried:

Back 61

Chemically combined with Hb

Front 62

The majority of carbon dioxide is carried:

Back 62

As bicarbonate ion (HCO3)

Front 63

Calculate Oxygen Delivery (DO2)
CaO2=16ml/dl & cardiac output 6.0 L/min.

Back 63

DO2= 6 (16x10)
DO2= 6 (160)
DO2= 960 ml

Front 64

There is a total of 14 g/dL hemoglobin (Hb) in the blood, of which 7.5 g is HbO2. What is the calculated SaO2 (%)?

Back 64

SaO2 = 7.5/14x100
SaO2 = 54%

Front 65

While receiving an oxygen concentration (FIO2) of 65%, a patient's PaO2 is 50 mmHg. What is most likely causing this problem?

Back 65

Significant shunting is present

Front 66

Hyperventilation is normally seen as the compensatory mechanism for___________.

Back 66

Metabolic Acidosis

Front 67

Why is the bicarbonate buffer system, considered an open buffer system?

Back 67

Its acid component (carbonic acid) is volatile.

Front 68

What is the ratio of HCO3- to dissolved CO2 that results in a pH of 7.40?

Back 68

20:1

Front 69

What describes respiratory alkalosis?

Back 69

The PaCO2 is less than 35 mmHg

Front 70

Primary metabolic alkalosis is associated with_____________?

Back 70

An increase in buffer base

Front 71

What might be used to correct metabolic alkalosis?

Back 71

Restoring normal fluid volume
Restoring normal K+ and Cl- levels

Front 72

An increase in the hydrogen ion concentration [H+] of the blood due only to an increase in the arterial PCO2 (hypercapnia), best describes which acid-base disorder?

Back 72

Acute respiratory acidosis

Front 73

Interpret the following set of ABG values: pH 7.22, PCO2 60mm Hg, HCO3 24 mEq/L

Back 73

Acute (uncompensated) respiratory acidosis

Front 74

Describe the state of "alkalemia"?

Back 74

the HCO2:CO2 ratio exceeds 30:1 and The blood pH exceeds 7.45

Front 75

What is the normal range of PAO2 - PaO2 gradient (A-a gradient) for a healthy young adult breathing room air?

Back 75

5 to 10 mmHg

Front 76

Which equation describes O2 delivery to the tissues?

Back 76

DO2 = Qt [CaO2 x 10]

Front 77

Describe the PaO2. What is it?

Back 77

Oxygen dissolved in the blood plasma.

Front 78

Under what conditions may even the delivery of 100% O2 not be sufficient to acheive a satisfactory arterial oxygen content?

Back 78

When physiologic shunting is present.

Front 79

A patient with a normal PaO2, SaO2 and cardiac output is exhibiting signs and symptoms of tissue hypoxia. What is the most likely cause?

Back 79

Anemic hypoxia

Front 80

How is the vast majority of O2 carried in the blood?

Back 80

Combined with Hb