Brainscape's Knowledge GenomeTM

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


See full index

Respiratory Physiology > Blood Gases and Transport > Flashcards

Blood Gases and Transport Flashcards

1
Q

What is cooperativity for hemoglobin?

A

the binding of one O2 increases the binding affinity of the other O2, 1 O2 coming off decreases the affinity of the other O2 binding the hemoglobin

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

What factors affect oxygen binding and release on hemoglobin?

A

oxygen tension, pH, pCO2, 2,3-BPG, and temperature

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

How does oxygen tension affect oxygen binding and release with hemoglobin?

A

it is high in the lungs and low in the tissues; drives the O2 on near the lungs and off near the tissues

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

How does pH affect O2 binding and release with hemoglobin?

A

acidity enhances the release of O2, lowering pH shifts oxygen dissociation curve to the right so O2 affinity is decreased

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

How does pCO2 affect O2 binding and release with hemoglobin?

A

increasing the concentration of CO2 at constant pH lowers oxygen affinity of Hb

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

How does 2,3-BPG affect O2 binding and release with hemoglobin?

A

2,3-BPG can bind to and stabilize deoxyhemoglobin lowering Hb affinity for oxygen, shift in the O2 sat curve to the right

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

How does temperature affect O2 binding and release with hemoglobin?

A

increase in temperature lowers Hb affinity for O2, exercise increases temp which helps O2 delivery to tissues

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

What causes BPG to accumulate at higher concentrations in the body?

A

acclimatization to high altitudes, chronic lung disease, anemia, right to left cardiac shunt, congenital heart disease, and pulmonary vascular disease, causing a decrease in oxygen affinity

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

How is fetal hemoglobin oxygen affinity compared to adult hemoglobin?

A

leftward shift because of gamma instead of beta chains, gamma lacks the two positively charged groups needed to bind 2,3-BPG and has a tighter association with O2

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

Why does fetal hemoglobin need to have a higher O2 affinity? What is the downside?

A

need to compete with mom’s hemoglobin so they get O2 in the placenta to take to their tissues, it is harder to offload to fetal tissues

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

What is the binging affinity of myoglobin compared to hemoglobin? Why is this important?

A

greater affinity, so under conditions of oxygen deprivation myoglobin will release O2, also necessary so when oxygen is rich it will be taken up to the myoglobin over the hemoglobin so it will be available for oxygen deprived situations

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

How does anemia effect O2 carrying capacity?

A

decreases O2 carrying capacity without altering P50 of blood, maintains saturation

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

How does polycythemia effect carrying capacity?

A

increase O2 capacity without altering P50, maintain saturation

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

How does carbon monoxide affect O2 carrying capacity?

A

binds to heme 200x greater affinity than O2, eliminate cooperative effect of oxygen binding to Hb

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

What is methemoglobin?

A

oxidation of heme iron from ferrous (Fe++) to ferric (Fe+++) results in methemoglobin, which is unable to release O2

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

What enzyme converts methemoglobin back to normal hemoglobin?

A

NADH-methemoglobin reductase (diaphorase I)

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

What is methemoglobinemia?

A

results from agents that oxidize ferrous ion, presence of abnormal hemoglobins, reduction in the ability to reduce heme ferric ions, or a combination; levels of 50% or greater= seizures or death; treat with reducing agents like methylene blue, also called hemoglobin M disease

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

What is the Bohr effect?

A

when oxygen binds to hemoglobin, protons are dissociated from histidine residues, and increase in H ions drives reaction to promote release of oxygen from Hb; decreased pH is associated with oxygen demand; increased metabolic rate results in increased production of CO2 and lactic acid and they promote the release of oxygen from Hb

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

What are the major forms of transport for CO2?

A

dissolved CO2, HCO3 formed by ionization of H2CO3 produced from CO2 and H2O catalyzed by Carbonic anhydrase, and attached to protein as carbamino groups mainly on the N-terminal amino group of deoxyhemoglobin which has a higher affinity for CO2 than oxyhemoglobin

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

What is the chloride shift?

A

bicarbonate-chloride carrier protein in erythrocyte membrane shuttles Cl and HCO3 in opposite directions; in the lungs HCO3 migrates into the cells to be converted to CO2 for exhalation and Cl returns to plasma

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

In what two ways does the binding of O2 displace CO2 from hemoglobin?

A

Haldane effect, release of hydrogen

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

What is the Haldane effect?

A

when O2 binds to Hb, Hb has a reduced ability to bind CO2 as carbamino hemoglobin and CO2 is released

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

Other than the Haldane effect how does O2 binding to Hb help offload CO2?

A

when O2 binds to Hb hydrogen is released and they turn and bind to HCO3 which dissociates to H2O and CO2. CO2 is released from the blood into alveoli to be expired

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What percent of CO2 transported back to the lungs is in the form of CO2, Hb-CO2, and HCO3?

A

CO2= 10%, Hb-CO2= 30%, HCO3= 60%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What forms of CO2 are measured on the electrolyte panel? What is it labeled as?

A

HCO3, H2CO3, and CO2; labeled as bicarb

26
Q

How can PaCO2 be calculated from and electrolyte panel?

A

pH= 6.1 + log HCO3/PCO2x0.03, pH and HCO3 values are on the electrolyte panel

27
Q

What is the normal range for PaCO2?

A

35-45 mmHg

28
Q

What is normal HCO3 level in the blood?

A

18-26 meq/L

29
Q

What is defined as acidosis?

A

process that results in net increase [H], defined as decrease HCO and/or increase in PaCO

30
Q

What is acidemia?

A

a low blood pH <7.35, acidemia implies acidosis but acidosis does not imply an acidemia

31
Q

What is alkalosis?

A

process that results in net decrease in [H]; defined by increase in HCO3 and/or decrease in PaCO

32
Q

What is alkalemia?

A

increase in blood pH >7.45, alkalemia implies alkalosis

33
Q

What is the difference between and osis and an emia?

A

osis is a process of an increase or decrease in an acid or a base; emia is a abnormal blood pH

34
Q

What low pH level is lethal and what happens at those levels?

A

depressed mental activity, coma, cardiac rhythm changes

35
Q

What high pH level is lethal and what happens at those levels?

A

> 7.8, mental excitability, tetany, seizures, and cardiac rhythm changes

36
Q

What does hypoventilation cause?

A

increased PaCO2, decreased pH, respiratory acidosis

37
Q

What does hyperventilation cause?

A

decreased PaCO2, increased pH, respiratory alkalosis

38
Q

What does an increase in HCO3 imply?

A

gain of base or lose acid; greater than 26meq/l

39
Q

What does a decrease in HCO3 imply?

A

gain acid or lose base; less than 18 meq/l

40
Q

How do you know the body is compensating for an acid/base disorder?

A

implies 2 processes present the primary process and the compensatory process

41
Q

What is the compensatory process for respiratory acidosis? alkalosis?

A

metabolic alkalosis; metabolic acidosis

42
Q

What is the compensatory process for metabolic acidosis? alkalosis?

A

respiratory alkalosis; respiratory acidosis

43
Q

What is it called if only one process is present in an acid base disorder?

A

acute or uncompensated

44
Q

What is it called if two processes are present in an acid base disorder?

A

usually due to compensation; Chronic- opposite but unequal, Mixed- opposite directions but nearly equal, and combined- same direction

45
Q

How do you tell which is the primary process and which is the compensation?

A

pH move toward normal, it is never smack dab normal 7.4, it points toward the primary disorder

46
Q

What are the steps for acid-base interpretation?

A

1)describe pH 2) describe the respiratory status PaCO3 3) describe the metabolic status HCO3 4) How many processes 5) Primary process v Compensation 6) Interpret acid-base status

47
Q

What is hypoxia?

A

cellular metabolic machinery shuts down (anaerobic metabolism), organ and tissue dysfunction (inadequate delivery or utilization of O2); can have hypoxia without hypoxemia- organ ischemia

48
Q

What is hypoxemia?

A

low arterial O2 (PaO2), can be due to Pbar or ventilation state (PaCO2), low PaO2 causes low O2 saturation, hemoglobin can increase to compensate; can have hypoxemia without hypoxia- mild chronic lung disease

49
Q

What is the O2 cascade?

A

level of O2 from lungs out to periphery; FiO2 atmospheric - 160, pass through humidity zone- 150, in the alveolus- 100, in the artery- 90, in the capillary- 90 to 40 site of tissue perfusion, 40-8 at the tissue level

50
Q

What is the alveolar air equation with room air?

A

PaO2= FiO2 (Pbar - PH2O) - (PaCO2/R); Pbar is barometric pressure, PH2O is vapor pressure, FiO2 is fraction inspired O2, PaCO2 is measured on ABG, typically 40 where R is the respiratory quotient 0.8

51
Q

How does altitude change FiO2?

A

it doesn’t it is always 21% in the atmosphere

52
Q

What is the efficiency measure of gas transfer?

A

the A-a gradient, PaO2/FiO2 ratio (P:F)

53
Q

As the PaO2 increases from 30 to 60 how does the content in the plasma change vs hemoglobin?

A

plasma increases 2 fold linearly; hemoglobin increases 5 fold, non-linear sigmoid curve

54
Q

What does a arterial blood gas measure and what does it calculate?

A

measure: pH, PaCO2, PaO2; calculates: HCO3, base excess

55
Q

What does a Co-Oximeter measure and what does it calculate?

A

measures: hemoglobin content, % CO2 hemoglobin, % methemoglobin, SaO2 (% O2 Saturation; calculates O2 content (CaO2)

56
Q

What is the difference between adequate and efficient oxygenation?

A

adequate: blood is red, things are ok not great, have time to think, O2 sat >or= 90, requires separate lab test (co-oximeter), don’t trust calculated sat you’ll miss monoxide poisoning; efficient: most of O2 that goes into lungs gets into blood, serious lung problem is very unlikely

57
Q

How is saturation calculated?

A

Hbgtot= Hgboxy + Hgbdeoxy + Hgbco + Hgbmet

58
Q

When is A-a gradient not useful?

A

patient has a high FiO2; FiO2>0.21, need to calculate P:F which is useful for trending a patient who is not on room air

59
Q

What is a normal A-a gradient? What does it imply?

A

age/4, efficient O2 transfer by the lung, hypoxemia is present but the lung is not the cause

60
Q

What does a wide A-a gradient mean?

A

implies inefficient O2 transfer by the lung, hypoxemia indicates a lung problem, could be caused by a left to right intracardiac shunt

61
Q

What are the four main causes of hypoxia? example? A-a gradient? What happens with high altitude?

A

decreased ventilation, ex. narcotic overdose, normal A-a; decreased V/Q, ex. asthma, pneumonia or CHF, increased A-a; increased shunt (V/Q=0), ex. mucus plug, ARDS, VSD, A-a very wide or high; decreased diffusion, ex. emphysema or fibrosis, A-a wide; decreased inspired O2- ex. high altitude, A-a normal

Respiratory Physiology (6 decks)

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