Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

SMP - Cardiopulmonary Exam 2 > Lecture 28 - Review and Clinical Cases > Flashcards

Lecture 28 - Review and Clinical Cases Flashcards

1
Q

With V/Q imbalance (<1), what will be the arterial PaCO2? How come? What about PaO2?

A

Normal at 40 because signals to the brain will cause hyperventilation

PaO2 will rise a little, but still hypoxemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Minute ventilation of V/Q imbalance?

A

High due to compensatory hyperventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

How would the A-a gradient due to anatomic shunt vary if PiO2 is increased? Why?

A

Increased because the gradient represents a % of blood that is not coming in contact with working alveoli and the PaO2 will be much higher than 100 mmHg like at room air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

How to distinguish between the 5 causes of hypoxemia?

  1. Low inspired PiO2
  2. Hypoventilation
  3. Diffusion limitations
  4. Shunt
  5. V/Q imbalance
A
  1. If PaCO2 is high then there HAS TO BE hypoventilation
  2. Calculate A-a gradient (normal in first 2 causes, elevated in last 3) - if normal, then the hypoventilation is the ONLY cause of the hypoxemia
  3. Check if putting patient on 100% O2 would allow raising the PaO2 above 500 mmHg
  4. If not, then it’s shunt. If it does work, then check DLCO to determine if it’s diffusion limitations or V/Q imbalance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Are both the amount of O2 bound to Hb and amount of O2 dissolved in blood dependent on PaO2?

A

YUP (Hb until it reaches 100% SaO2)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which is more important for O2 delivery to tissues: PaO2 or Hb saturation?

A

Hb saturation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Is CO2 more perfusion or diffusion limited?

A

Perfusion limited

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

At rest, with a low FiO2 or low PAO2, will the blood be able to reach 100% saturation of Hb?

A

YUP

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

How will doubling the diffusion capacity in a normal person affect PaO2?

A

Normal because PaO2 will simply equilibrate with PAO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How will doubling the diffusion capacity in a normal person affect max O2 uptake at extreme altitude? Explain.

A

Increase it because the PAO2 will be so low that increasing the diffusion capacity will help

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is the PcO2 in pulmonary capillary tension in a normal person at rest?

A

80 mmHg or more!

For 2/3 of capillary: 100 mmHg
For 1/3: 40 to 100 mmHg

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Would increasing afterload increase SvO2 in a septic shock patient?

A

NOPE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

3 ways to improve CO?

A
  1. Increase preload
  2. Reduce afterload
  3. Iniotropes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What does aspirin overdose cause?

A

TWO primary acid-base disorders:

  1. Metabolic acidosis due to salacylic acid to develop in blood
  2. Respiratory alkalosis due to hyperventilation caused by effect of salicylic acid on brain
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

How to calculate A-a gradient when given PaCO2 and PaO2?

A

PAO2 = 150 - PaCO2/0.8

A-a gradient: PAO2 pv - PaO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

If PaCO2 is high and it is due to respiratory acidosis, does that automatically mean hypoventilation?

A

YESSSSSS

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

If the A-a gradient is elevated and you have respiratory acidosis, what does this mean?

A

Means there is another one of these 3 happening with the hypoventilation:

  1. Diffusion limitations
  2. Shunt
  3. V/Q imbalance
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Why would a decrease in alveolar space cause an increase in PaCO2?

A

Decrease alveolar minute ventilation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Why would someone with asthma have turbulent flow?

A

Gas velocity increase to a greater extent than the decrease in radius to maintain the same volume of gas incoming => Re increases

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

Why do the normal anatomical shunts not cause a PACO2-PaCO2 gradient?

A

Because CO2 is much more soluble in blood and the extra CO2 will simply diffuse and will not disturb the PaCO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

Can you have hypoxemia without hypoxia?

A

NOPE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Can you have hypoxia without hypoxemia?

A

YUP (like in anemia)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Why doesn’t CO poisoning cause reduced PaO2?

A

The PaO2 refers to the partial pressure of the gas in the blood. As there is no appreciable PaCO (carboxyhemoglobin) there is no effect on the PaO2

24
Q

Why is PaCO2 normal in low V/Q?

A

Because the peripheral chemoreceptors will detect any rise in the PaCO2 and signal the brain stem to increase the minute ventilation to keep the PaCO2 at the normal range

25
Q

Are PeCO2 and PACO2 the same?

A

NOPE! Ve x PeCO2 = VA x PACO2

Ve = VD + VA

26
Q

Why is the exchange ratio of CO2 to O2 the same as the respiratory quotient at the tissues?

A

Because Rq is based on how much ATP we can generate with each source of food and how much O2/CO2 will be involve AND because the lungs need to make sure to have the same ratio to ensure they are disposing of the CO2 being produced

27
Q

Why is the A-a gradient elevated in the bottom 3 physiological causes of hypoxia?

A
  • Diffusion limitations and shunt: because the PaO2 is low (PAO2 is normal)
  • V/Q imbalance: because the PAO2 is low in SOME alveoli
28
Q

Main important difference between shunt and V/Q imbalance?

A

Physiologic shunt: NO ventilation

V/Q imbalance: REDUCED ventilation

29
Q

Physiologic cause(s) of hypoxia in acute status asthmaticus?

A

V/Q imbalance

30
Q

Physiologic cause(s) of hypoxia in pneumonia?

A
  1. Diffusion limitation
  2. V/Q imbalance
  3. Potential shunt if total occlusion of some airways
31
Q

Physiologic cause(s) of hypoxia in COPD?

A
  1. V/Q imbalance due to chronic bronchitis

2. Diffusion limitation due to mucus and emphysema

32
Q

Physiologic cause(s) of hypoxia in heroin overdose?

A

Hypoventilation

33
Q

Physiologic cause(s) of hypoxia in CO poisoning?

A

HYPOXIA, none of them

34
Q

What test to do if diffusion issue is suspected but the DLCO is normal?

A

Exercise test to decrease time available for diffusion to happen

35
Q

Why does pulmonary embolism cause hypoxemia?

A

Increased amount of dead space => decreased SA

36
Q

Is elevated A-a gradient ever due to increased PAO2?

A

Yes, in some athletes who have much larger lungs (max PaO2 of 120 mmHg)

37
Q

Can PaO2 be 150 at room air?

A

NOPE!! A-a gradient would be negative and that is just cray

38
Q

How does a left sided pneumothorax affect peak and plateau pressures?

A

Both elevated

39
Q

How does a endotracheal tube cuff leak affect peak and plateau pressures?

A

Low peak

Unable to read plateau

40
Q

How does a pulmonary embolism affect peak and plateau pressures?

A

Both normal

41
Q

How does an acute asthmatic response affect peak and plateau pressures?

A

Elevated peak

Normal plateau

42
Q

How does the displacement of a volume mode ventilator tube into a main stem bronchus affect peak and plateau pressures?

A

Both elevated due to decreased total volume

43
Q

What is ARDS?

A

Acute respiratory distress syndrome where you have narrowing of the airways and atelectasis + diffusion issues

44
Q

What intervention leads to the highest increase in DO2?

A

Blood transfusion to increase Hb content

45
Q

Effect of PEEP on heart?

A

Increased afterload => more work to do

46
Q

What does increasing PEEP increase?

A

FRC, so: PaO2 and SaO2

47
Q

What happens if plateau pressure exceeds 30-35 cm of H2O?

A

Alveoli pop = pneumothorax

48
Q

How do you increase one of the West Zones of the lung?

A

Make other zones like itself

e.g. to increase Zone 1 you would want to increase airway pressures in the rest of the lung or decrease Pa (diuresis)

49
Q

What will cause sudden decrease in PeCO2?

A

Pulmonary embolism because it causes a sudden increase in dead space

50
Q

What is end tidal pressure?

A

Pressure of a gas coming out of the mouth

51
Q

Would pulmonary embolism shift the trachea?

A

NOPE

52
Q

How is FRC affected by obstructive lung diseases? What is this called? 2 names

A

Increased due to air trapping causing AUTO-PEEP = intrinsic PEEP

53
Q

How to decrease expiratory time if you are at fixed RR?

A

Increase inspiratory time

54
Q

3 ways of increasing expiratory time?

A
  1. Decrease inspiratory time
  2. Decrease TV
  3. Decrease RR
55
Q

Does pulmonary embolism decrease diffusion capacity?

A

Yes, less surface area

56
Q

Does pulmonary embolism lead to hypoventilation?

A

NOPE, actually hyperventilation to decrease PaCO2 since diffusion of CO2 is impaired

57
Q

Does pulmonary embolism cause decrease lung compliance?

A

NOPE

SMP - Cardiopulmonary Exam 2 (15 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions