Brainscape's Knowledge GenomeTM

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


See full index

Pulmonology > Arterial Blood Gases > Flashcards

Arterial Blood Gases Flashcards

1
Q

facts about ABG

A
  • it’s serious - only get if needed
  • remember Allen’s test
  • cost is ~ $75
  • apply pressure for 5 min. after
  • pt is usually being given chest compressions - complicates finding pulse
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

oxygen tension

A

measure of molecular oxygen dissolved in blood

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

hgb saturation

A

oxygen bound to hgb

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

what drives oxygen into the tissues?

A

oxygen tension

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

when do you get a Hgb saturation of 95-99%?

A

when PaO2 is 80-90 mmHg (measured w ABG)

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

During resuscitation, if PaO2 is less than 80 mmHG, what pulmonary causes would you consider?

A
  1. 100% oxygen is not being delivered
  2. incorrect intubation
  3. aspiration of gastric contents/solids
  4. pulmonary edema and/or
  5. pneumothorax
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

During resuscitation, if PaO2 is less than 80 mmHG, what cardiac causes would you consider?

A
  1. poor chest compressions
  2. dysrhythmias
  3. pump failure
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What determines gas exchange?

A

CO2 - if there is no blood flow through the lungs, won’t have gas exchange

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

what is the result of too much O2?

A
  • partial pressure will increase causing free radical formation
  • ARDA; IRDS; neuro issues
  • maintain O2 sat between 94-99% - not 100%
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

what percent of hgb is normally saturated at any given time?

A

-94-99%

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

What is the relationship between % saturation of hgb and PO2?

A
  • a small drop in hgb saturation will cause a significant drop in pO2
  • ex: 80% saturation of hgb = 50% PO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

reading a CO2 detector

A
  • purple = problem
  • tan = think
  • yellow = yes

-it’s purple to start out, CO2 changes it yellow; if intubated incorrectly like in the right mainstem bronchus, it will be tan

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

waveform capnography

A

quantitative measure of CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

PetCO2

A
  • PCO2 right before you breathe in

- if it drops below 10 mmHg, need to push harder on chest compressions

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is the product of normal metabolism?

A
  • 2 forms of acid:
  • respiratory
  • metabolic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

respiratory acid formed in normal metabolism

A

-volatile: carbonic

H2CO3 H2O +CO2

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

metabolic acid formed in normal metabolism

A

-larger molecular size:
from amino acids, fats, carbs, phosphoric, sulfuric: excreted by kidneys

H+ + HCO3

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

normal metabolism total equation

A

H+ + HCO3- H2CO3 H2O + CO2

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

what happens during anaerobic metabolism?

A
  • ex: cardiac arrest/DKA
  • production of lactic acid accumulates, hence metabolic acidosis
  • strong acids combine w/ sodium bicarb resulting in a weak acid and neutral salt
  • the weak carbonic acid is blown off by the lungs as CO2
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

anaerobic metabolism equation

A

HAcid + NcHCO3 –> H2CO3 + NaA NaA + H2O + CO2

21
Q

CO2 and water forms ________, which can then be broken down into _____ and ___.

A

CO2 and water forms carbonic acid, which can then be broken down into bicarb and H+.

22
Q

what are the 2 ways in which you can get rid of acid?

A
  • get rid of H+

- get rid of CO2

23
Q

how to effect pH through respiratory rate

A
  • getting rid of CO2 leads to no formation of carbonic acid

- retaining CO2 leads to formation of more acid and more H+

24
Q

buffer systems consist of what?

A
  • a weak acid

- the salf of the weak acid

25
Q

purpose of buffering systems

A

to prevent the accumulation of carbonic and metabolic acids that produce marked changes in acidity of the body

26
Q

What is the most important buffering system in the body?

A

sodium bicarbonate and carbonic acid system

27
Q

what is the weak acid in the sodium bicarb/carbonic acid buffer?

A

carbonic acid

28
Q

what is another example of a buffer system in the body?

A
  • hgb

- if it dumps all O2 in the periphery and takes nothing but CO2, it’s serving as a buffer for the RBC

29
Q

pH

A
  • hydrogen ion concentration

- ration of base:acid

30
Q

what is the ratio in pH

A
  • NaHCO3:H2CO3
  • Base:Acid
  • 20:1
31
Q

changes in PaCO2 result in changes of what?

A

H2CO3 (NOT NaHCO3)

because an acid cannot react w/ its own salt, so only the ratio b/w the two changes

32
Q

as [H+] double or halves, what is the result?

A
  • pH change of 0.3

- therefore, small pH changes signify marked accumulation/depletion of acid

33
Q

normal ABG values

A
  • pH: 7.35-7.45 (use 7.4 as reference)
  • PaO2: 80-90 mmHg
  • PaCO2: 35-45 mmHg (use 40 as reference)
  • HCO3: 21-28 mEq/l
34
Q

golden rule #1

A

A change in PaCO2 of 10 mmHg = up/down pH change of 0.08 units

35
Q

golden rule #2

A

A change in HCO3 of 10 mEql = up/down pH change of 0.15 units

36
Q

if the calculated pH approximates the real pH, what is the mechanism?

A

pure respiratory

37
Q

if the calculation pH do not approximate the real pH, what is the mechanism?

A

it must have a metabolic component

38
Q

how do you treat respiratory and metabolic acidosis?

A

by increasing ventilations and giving a base (ex: NaHCO3)

driving the equation to the right

39
Q

base deficit is d/t what?

A

loss of sodium bicarb from ECF

40
Q

base deficit expresses…

A

the deficit of sodium bicarb in mEq for a L of ECF

41
Q

golden rule #3

A

base deficit X pt. weight in kg / 4

42
Q

metabolic acidosis is treated with …

A

IV sodium bicarb

43
Q

if the ABG is out of whack, but the pH is normal, what is going on?

A

compensation

44
Q

compensation

A
  • in chronic disease, lungs/kidneys may compensate for disease in the other
  • if pH has returned to 7.35 - 7.45, the compensated
  • if not, uncompensated
45
Q

in COPD, what do the kidneys do?

A

retain base

46
Q

in hyperaldosteronism, what do the lungs do?

A

retain CO2 (increased renal absorption of bicarb)

47
Q

if pH is increased…

A

= alkalosis

  • if PaCO2 is in same direction = metabolic
  • if PaCO2 is in opposite direction = respiratory
48
Q

if pH is decreased…

A

= acidosis

  • if PaCO2 is in same direction = metabolic
  • if PaCO2 is in opposite direction = respiratory

Pulmonology (11 decks)

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