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CPR > Exam 4 > Flashcards

Exam 4 Flashcards

1
Q

What happens to the oxygen saturation and content if Hb concentration falls?

A

The oxygen saturation stays the same (bc all the Hb are fully saturated) but the concentration of oxygen decreases bc there is less Hb available to carry O2

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2
Q

What are the major determinants of oxygen delivery to the tissues?

A

Cardiac output and Hb concentration

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3
Q

Describe hypoxic pulmonary vasoconstriction (HPV)

A

When there is a decreased in PAO2, blood flow to that alveolus will be constricted. This is the body’s way to prevent a build up of CAO2 within that non-ventilated alveolus. It helps to ensure adequate matching of ventilation and perfusion, which is helpful for preserving blood oxygenation.

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4
Q

What effect does prolonged low PaO2 have on Hb?

A

Decreased PaO2 –> increase in erythropoietin concentration

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5
Q

Describe carboxyhemoglobinemia

carbon monoxide poisoning

A

Occurs when large amounts of gas are inhaled –> increased CO levels in the blood which impairs O2 delivery

PaO2 = normal
SpO2 = normal
CvO2 & SvO2 = Low

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6
Q

Describe methemoglobinemia

A

Ferrous iron 2+ oxidizes to ferric iron 3+ –> conformation change in Hb which prevents O2 from binding to Hb and impairs O2 delivery

Important note: Pulse ox usually reads 87-88% and pt does not respond to supplemental O2

Can be caused by dapsone (pneumocystis prophylaxis), benzocaine or cetacaine.

PaO2 = normal
SpO2 = low
CvO2 & SvO2 = Low

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7
Q

Describe cyanide poisoning

A

Normal O2 delivery but the mitochondria are unable to utilize the O2 bc cyanide inhibits cytochrome oxidase –> more O2 in mixed venous blood.

Hallmark of cyanide poisoning: high mixed venous blood O2 content and it’s very pink looking

PaO2 = Low or normal
SpO2 = low or normal
CvO2 & SvO2 = High

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8
Q

Describe the Haldane Effect

A

The oxygenation of Hb decreases the ability of Hb to carry CO2 as carbamino groups (but does not affect the bicarbonate rxn).
As O2 binds to Hb at the lungs, it releases CO2 to diffuse into the alveoli

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9
Q

Describe the Bohr Effect

A

As Co2 is loaded on to the RBC, the H+ binds to the Hb –> T state configuration –> release of O2 to the tissues

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10
Q

Name two basic factors that can cause hypercarbia and hypocarbia

A

Hypercarbia is > 45 mmHg and occurs as a result of low alveolar ventilation or increased metabolic production of CO2

Hypocarbia is < 35 mmHg and occurs as a result of high alveolar ventilation or decreased metabolic production of CO2

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11
Q

Name the main muscle used for inspiration along with other muscles that can be used if needed.

A

Diaphragm
External intercostal
SCM
Scalene

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12
Q

Why don’t the alveolar collapse when we breathe?

A

Bc of surfactant (a detergent to decrease surface tension) produced by type II pneumocytes.

If there is no surfactant –> atelectasis

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13
Q

Name a process that decreases FRC and name a process that increases FRC

A

Fibrosis decreases FRC causing the lungs to want to recoil more –> greater pressure inward than outward.

Loss of alveolar elasticity as with emphysema increases FRC causing the chest wall to want to recoil less –> greater pressure outward than inward.

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14
Q

What is radial traction and where is it greatest?

A

Radial traction pulls the airways open to a higher caliber and decreases resistance to airflow. As you move from a lower to higher lung volume, the alveoli exert greater radial traction on the airways.

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15
Q

When does turbulent and laminar flow occur?

A

Turbulent flow occurs in larger caliber airways with higher gas velocity. A tumor or other lesion that can narrow the airway can –> a increase in gas velocity due to smaller radius thereby causing turbulent flow.

Laminar flow occurs in smaller caliber airways with lower gas velocity

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16
Q

What does low PIO2 mean and give an example. How does it affect (A-a)changeO2?

A

Low PIO2 means you are breathing less O2

An example would be higher altitude.

(A-a)changeO2 is normal

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17
Q

What does hypoventilation mean and give an example? What is its hallmark? How does it affect (A-a)changeO2?

A

Hypoventilation the level of alveolar ventilation is insufficient for O2 influx and CO2 elimination.

Ex: Opiate overdose

Hallmark = increased PaCO2

(A-a)changeO2 is normal

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18
Q

What is diffusion impairment and give an example? Does it cause hypoxemia? How does it affect (A-a)changeO2?

A

Diffusion abnormalities that –> slower rate of O2 transfer across alveolar capillary bed.

Ex: Exercise at high altitudes

It rarely causes hypoxemia bc there is sufficient time for the Hb to become fully oxygenated. However, if the pt engages in activity, an increased cardiac output can shorten the capillary transit time –> decreased PaCO2

(A-a)changeO2 is increased

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19
Q

What is a shunt and example of a shunt. ? What is its hallmark? How does it affect (A-a)changeO2?

A

A shunt causes blood to pass from the venous system to the arterial system without going through gas exchange.

Ex: Pneumonia

Hallmark = Administration of O2 does not fully correct the PaO2

(A-a)changeO2 is increased

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20
Q

What is a VA/Q mismatch and give an example? How does change in VA/Q impact PaO2 and PACO2? How does it affect (A-a)changeO2?

A

With VA/Q mismatch, main problem is with gas exchange.

Example: COPD exacerbation or asthma

When ventilation > blood flow –> HIGH VA/Q –> high PaO2 and low PACO2
When blood flow > ventilation –> LOW VA/Q –> low PaO2 and high PACO2

(A-a)changeO2 is increased

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21
Q

Describe the 4 Steps in determining causes of hypoxemia.

A

Step 1: Is the pt at high altitude or breathing a low FIO2? If yes, then PIO2 is at least one cause of hypoxemia.

Step 2: Is the PaCO2 > 45 mmHg? If yes, then hypoventilation is at least one cause of hypoxemia.

Step 3: Is the (A-a)changeO2 normal or increased? If no, then there is no other process besides hypoventilation and/or PIO2. If yes, then pt has a mismatch or shunt.

Step 4: Does the pt respond to O2? If yes, then mismatch. If no, then shunt.

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22
Q

What does spirometry provide information about?

A

Airflow

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23
Q

What is a normal FEV1/FVC ratio? If the ratio is lower than normal what does that mean? What does the FEV1 alone tell you?

A

Normal FEV1/FVC ratio > 0.70

< 0.7 mean there is obstruction

FEV1 alone tells you the degree of severity

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24
Q

The lung volume test provides what information? What are the abnormal values for the information and what is signify?

A

Lung volume test prodivdes TLC and RV

TLC > 120% means hyperinflation
TLC <80% means restriction

RV > 120% means air trapping

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25
Q

What information does diffusion capacity provide? What is the abnormal value for DC and what does it mean? What does a normal DC value mean? What does DC not tell you?

A

Diffusion capacity provides information regarding the amount of surface area available for diffusion.

DC < 80% means decreased area for gas exchange so think EMPHYSEMA
Normal DC (>80%) means think ASTHMA or UPPER AIRWAY OBSTRUCTION

DC does NOT tell you how well diffusion works!

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26
Q

Name the values for a positive bronchodilator (BD) response test. What does BD test evaluate?

A

Pos BD response is either FEV1 or FVC increased by 12% and 200ml.

BD evaluates the reversibility of airflow obstruction. A pos BD test means the airflow obstruction is reversible.

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27
Q

Describe how the flow-volume loop would look with an obstruction. Describe how it would look with a restriction.

A

Obstruction: the top exhalation portion would be concave

Restriction: The width of the loop would be reduced.

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28
Q

Describe how the flow-volume loop would look with an intrathoracic obstruction. And extrathroacic obstruction.

A

Intrathoracic obstruction: the top exhalation portion would be flatter

Extrathroacic obstruction: the bottom inhalation portion would be flatter

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29
Q

A restricted pt will present with what kind of TLC (high or low?) And if their DLCO is low? DLCO normal?

A

Restriction = low TLC

If DLCO is low = intra-pulmonary source of restriction

If DLCO is normal = extra-pulmonary source of restriction

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30
Q

Autonomic control of breathing is controlled by what?

Voluntary control of breathing is controlled by what?

A

Autonomic control = Brainstem (pons and medulla)

Voluntary control = cerebral cortex

31
Q

The peripheral and central chemoreceptors are each sensitive to changes it what?
And where are they located?

A

Peripheral chemorecpetors are sensitive to changes in O2. They are located in the aortic arch and carotid bodies.

The central chemoreceptors are sensitive to changes in CO2. They are located in medulla.

32
Q

When there is an increase in O2, what is the response of the chemoreceptors?

A

Increase in O2 –> peripheral chemorec to decrease ventilation

33
Q

When there is an increase in CO2, what is the response of the chemoreceptors?

A

Increase in CO2 –> central chemorec to increase ventilation

34
Q

As PaO2 decreases, how does that affect ventilatory sensitivity to PACO2?

A

Decrease in PaO2 –> increased sensitivity to PACO2

35
Q

A primary disorder of ventilatory control is caused by what?

A

Caused by a CNS disorder –> hyper or hypoventilation

36
Q

Name the four secondary disorders of ventilatory control we learned about.

A

Obesity Hypoventilation Syndrome (OHS)
Obstruction Sleep Apnea (OSA)
Central Sleep Apnea
Sleep-Related Hypoventilation (SRHV)

37
Q

What is the pathogenesis for obstructive hypoventilation syndrome?

A

Pathogenesis for OHS:
Impaired chest wall mechanics: compliance is decreased
Impaired muscle function
Displaced diaphragm → impairs efficiency of diaphragm contraction
Altered ventilatory response to CO2 and hypoxemia → lack of drive
Upper airway obstruction

38
Q

How is obesity hypoventilation syndrome characterized?

A

BMI > 30 and PaCO2 > 45 mmHg

39
Q

Name some clinical manifestations of OHS

A 
The low PaO2 causes increased erythropoietin secretion from the kidney, which can lead to increased hemoglobin concentration (polycythemia)
Dyspnea with exertion
Systemic HTN
CHF
Angina
40
Q

What will the PFT and ABG read for a pt with obesity hypoventilation syndrome?

A

Decreased expiratory reserve volume

Low FRC

TLC and VC are decreased

DLCO is normal or low

FEV1/FVC is normal

ABG: respiratory acidosis

41
Q

What is the tx for OHS?

A

Lose weight and treat nocturnal airway obstruction

42
Q

Describe Obstruction Sleep Apnea.

A 
Repeated reduction (hypopnea) or complete cessation (apnea) of inspiratory flow due to partial or complete obstruction. 
INSPIRATORY EFFORT IS STILL MAINTAINED!!!
43
Q

Name some factors that promote airway collapse

A

Pharyngeal dilator muscle activity which maintains upper airway tone and counteracts extra luminal forces.

They are activated by negative airway pressure and increased PCO2.

Extra soft tissue (fat) around the neck

Low lung volume → decreased compliance and contributes to collapse

Airway size: narrow airway and/or large anatomic features→ more prone to collapse

Fluid shifts: from legs toward neck in supine position

Unstable ventilatory control

44
Q

Name some chronic pathophysiology that can occur with Obstructive Sleep Apnea

A 
Sympathetic system activation
Vascular endothelial dysfunction
Oxidative stress &amp; inflammation
Hypercoagulability
Metabolic dysfunction
Adverse cardiovascular outcomes: HTN, MI, stroke, HF, Excessive sleepiness 
Diminished cognitive outcomes.
45
Q

Describe the clinical features of Obstructive Sleep Apnea

A

Partners report loud snoring w/pauses!
Daytime sleepiness
Neck circumference >16” for women and >17” for men
Narrow posterior oropharynx, enlarged tonsils, enlarged tongue and uvula.

There are few more in the syllabus.

46
Q

How do you diagnose Obstructive Sleep Apnea?

A

Polysomnography to monitor cardiorespiratory physiology (to include abdominal and chest excursion, nasal/oral airflow and oximetry).

Apnea-hypopnea index of > or = 5 is dx for OSA.

47
Q

What is the tx for Obstructive Sleep Apnea?

A 
Lose weight
No alcohol or sedative before bed
avoid supine position
CPAP
Mandibular advancement device 
or surgery if all else fails.
48
Q

What are the key findings with Obstructive Sleep Apnea?

A

Episodic cessation and reduction of airflow w/ongoing throacic and abdominal movements

49
Q

Describe Central Sleep Apnea and what it is commonly caused by.

A

Episodes of apnea and/or hypopnea resulting from low or no respiratory effort occurring in a cyclic fashion.

Commonly caused by cardiac or CNS dysfunction

50
Q

Pts with both CHF and Central Sleep Apnea can experience what special kind of breathing? How is the breathing characterized?

A

Cheyne Stokes Breathing characterized by alternating hypopnea and hyperpnea with a crescendo-decrescendo tidal volume.

ABSENCE OF CHEST WALL MOVEMENT!!!

51
Q

What is the pathogenesis for Cheyne Stokes Breathing?

A

Mainly caused by prolonged circulation time (due to HF) and over-responsive chemoreceptors.
They hyperventilate –> low CO2 –> chemoreceptors to initiate stop breathing –> high CO2 –> central drive kicks in –> hyperventilation, then the whole process starts all over again.

52
Q

What is the treatment for Central Sleep Apnea?

A

Treat HF, CPAP, and O2

53
Q

What is Sleep-Related Hypoventilation?

A

Abnormally high PaCO2 during sleep. Usually seen with pt that use chronic opioids or benzodiazepines, that are obese, have severe COPD or neuromuscular disease

54
Q

What is the diagnosis and treatment for Sleep-Related Hypoventilation

A

Dx: Polysomnography

Tx: CPAP

55
Q

What are the two factors that affect airflow? (hint: what is the equation for airflow?)

A
  1. decreased driving pressure
  2. increased airway resistance

airflow = pressure change / airway resistance

56
Q

What will the PFTs look like for obstructive diseases? How will the flow-volume loop look?

A 
FEV1/FVC = decreased!!!!!
FEV = decreased
FVC = preserved
TLC = can be hyperinflated
RV = can be airtrapping

Flow volume loop is concave in the top portion

57
Q

Asthma is an __________ process that has ______ and _______ symptoms of _______, airflow ______, and airway _____-responsiveness.

A

Asthma is an inflammatory process that has variable and recurring symptoms of dyspnea, airflow obstruction, and airway hyper-responsiveness.

58
Q

Name three mechanisms to airflow obstruction in asthma

A
  1. Secretions in airway lumen
  2. Smooth muscle hypertrophy and contraction
  3. Mucosal edema
59
Q

Will the bronchodilator response for a pt with asthma be positive or negative and why?

A

The BD test will be POSITIVE bc asthma is a REVERSIBLE airflow obstruction

60
Q

What are the three factors that must be controlled for adequate management of asthma?

A
  1. medications
  2. Eliminate control triggers (dust mites, mold, pollution
  3. Identify stressors (smoking in homes, stressful school environment)
61
Q

COPD is a chronic condition (a syndrome) characterized by _________ symptoms, ______ obstruction, and ________ reversibility.

A

COPD is a chronic condition characterized by respiratory symptoms, airflow obstruction, and incomplete reversibility.

62
Q

Name the two disease processes that lead to COPD and describe them. What are they both characteristic of (hint it’s a ratio)?

A
  1. Emphysema: Defined anatomically- irreversible destruction of alveolar walls
  2. Chronic bronchitis: Defined by hx- productive cough > 3 months/year for > or = 2years

Both are characteristic of a low FEV1/FVC ratio

63
Q

In the developed world, what is COPD most commonly caused by? In the developing world, what is COPD most commonly caused by?

A

Developed world: smoking!

Developing word: indoor air pollution, work exposure, outdoor pollution

64
Q

Name three mechanisms to airflow obstruction in COPD

A
  1. Secretions in airway lumen
  2. Smooth muscle hypertrophy and contraction
  3. Loss of radial traction
65
Q

If there is a decrease in ventilation only, how does that affect the level of oxygen in the blood?
What if their ventilation and perfusion are BOTH decreased?

A

Decreased ventilation only –> hypoxemia

Decreased ventilation and perfusion –> less hypoxemia and preserved VA/Q ratio

66
Q

How would an overall spirogram look for COPD pt?

A

The overall spirogram will be elevated in comparison to a normal person

67
Q

Why do COPD pts have higher FRCs?

A

W/COPD the recoil forces of the chest wall are > then lungs → chest walls pulling the lungs to a higher volume

68
Q

What are the effects of hyperinflation on contractility?

A

Flattened diaphragms cannot contract effectively –> decreased airflow

69
Q

What is required for the dx of COPD?

A

Must have a REDUCED FEV1/FVC ratio to dx COPD!!!!

70
Q

Can you dx COPD based on chest x-ray?

A

NO!!!! You still need spirometry!!

71
Q

Name a short-acting beta agonist and long acting beta agonist.

A

Short acting: Albuterol

Long acting: Salmeterol and Formoterol

72
Q

Name an short and long acting antimuscarinic

A

Short: Ipratropium

Long: Tiotropium

73
Q

What is the management for COPD exacerbations?

A
  1. Oral prednisone
  2. Albuterol
  3. Azithromycin
74
Q

If the initial regimen for COPD is not working, what can you add to augment the regimen?

A

If initial regiment was long-acting Beta-agonist, then add inhaled corticosteroid (Fluticasone)

If initial regiment was long-acting antimuscarinic, then add steroid-beta agonist combination

CPR (3 decks)

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