Respiratory pathophysiology Flashcards

(87 cards)

1
Q

Are there sympathetic nerve endings in airway smooth muscle?

A

No, but beta -2 receptors are well represented.

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2
Q

What are the beta-2 receptors in the airway smooth muscle activated by?

A

catecholamines circulating in the systemic circulation

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3
Q

The beta -2 receptors in the airway smooth muscle is coupled to what proteins?

A

Gs protein

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4
Q

activation of the B2 receptors turns on the Gs protein, and this activates what?

A

adenylate cyclase

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5
Q

what does adenylate cyclase activate?

A

cAMP

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6
Q

What type of messenger is cAMP?

A

2nd messenger

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7
Q

along with protein kinase A, cAMP reduces what?

A

Ca+2 release from the sarcoplasmic reticulum

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8
Q

What does a reduction in Ca+2 from the SR ultimately cause?

A

reduction in muscle contraction and promotion of bronchodilation

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9
Q

when is the bronchodilation pathway by catecholamines turned off?

A

when phosphodiesterase 3 deactivates cAMP by converting it to AMP

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10
Q

What does NO do to smooth muscle?

A

it is a potent smooth muscle relaxant

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11
Q

Phospholipase C
Leukotrienes
Inositol triphosphate
These are all chemicals that do what to the airway?

A

increased airway resistance

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12
Q

Beta 2 agonists MOA?

A

B2 stimulation which increases cAMP and causes a decrease in Ca+2 (leading to bronchodilation)

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13
Q

name some Beta 2 agonists?

A

albuterol
salmeterol
metaproterenol

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14
Q

Anticholinergics MOA?

A

M3 antagonism leading to decreased IP3 which causes decreased Ca+2 (bronchodilation)

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15
Q

Name some anticholinergics?

A

atropine
glycopyrrolate
ipratropium

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16
Q

Corticosteroids (inhaled) MOA?

A

stimulates intracellular steroid receptors and regulates inflammatory protein synthesis which causes a decrease in airway inflammation and a decrease in airway hyper responsiveness

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17
Q

Cromolyn MOA?

A

Stabilizes mast cell membranes which decreases mediator release and provides prophylaxis for 1-2 hours

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18
Q

Leukotriene Modifiers MOA?

A

Inhibits 5 lipoxygenase enzyme which decreases leukotriene synthesis

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19
Q

Examples of Leukotriene modifiers?

A

zileuton
Montelukast
pranlukast
zafirlukast

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20
Q

Methylaxanthines MOA?

A

Inhibits phosphodiesterase leading to a decrease in cAMP

Releases endogenous catecholamines

Inhibits adenosine receptors

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21
Q

What volumes do pulmonary function tests measure?

A

static lung volumes

dynamic lung volumes

diffusing capacity

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22
Q

What is static lung volume?

A

how much the air the lungs can hold at a single point in time

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23
Q

what is dynamic lung volumes?

A

how quickly air can be moved in and out of the lungs over time

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24
Q

what is diffusing capacity?

A

How well the lungs can transfer gas across the alveolocapillary membrane

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25
What are the static lung volumes?
How much air the lungs can hold at a single point in time ``` TLC FRC IRV ERV RV IC Vt VC ```
26
Which lung volumes provide an assessment of airway resistance and lung recoil?
dynamic lung volumes
27
What is FEV1?
Forced expiratory volume in 1 second. volume of air that can be exhaled in one second.
28
What is the normal value for FEV1
> 80% predicted value
29
Which dynamic lung volumes are effort dependent?
FEV1 | FVC
30
This dynamic volume takes age into account and it declines with age?
FEV1
31
What is forced vital capacity (FVC)?
Volume of air that can be exhaled after a deep inhalation
32
What is the normal value of FVC for male and female?
``` Male = 4.8 L Female = 3.7 L ```
33
What is the normal value of FEVI to FVC?
75 - 80%
34
Which dynamic volume measures airflow in the middle of expiration?
Forced expiratory flow at 25-75% vital capacity
35
Which pulmonary function test is the best test of airflow in the small airways?
Forced expiratory flow at 25-75% vital capacity
36
What is a normal value for forced expiratory flow at 25-75% vital capacity?
100 +/- 25% predicted value
37
What is Maximum voluntary ventilation (MVV)?
Maximum amount of air that can be inhaled and exhaled over 1 minute
38
which pulmonary function test is the best test of endurance?
MVV
39
What is the normal value of MVV for males and females?
``` Males = 140-180 L Females = 80-120 L ```
40
What is the abbreviation for Diffusing capacity for carbon monoxide?
DLCO or Dlco
41
Which test tests the lung's ability to exchange gas?
Diffusing capacity for carbon monoxide test
42
Volume of carbon monoxide that can transverse the aleveolarcapillary membrane per a given alveolar partial pressure of CO describes?
Diffusing capacity for carbon monoxide
43
What do flow volume loops allow you to do?
differentiate between obstructive and restrictive respiratory disease
44
On a flow-volume loop between what two points does inhalation occur?
inhalation occurs between residual volume and lung capacity
45
on a flow volume loop where is flow zero?
flow is zero at the line that traverses the loop which is also at end inspiration.
46
When does flow occur on a flow volume loop?
flow occurs at inspiration and expiration
47
on a flow volume loop in what direction does volume become more positive?
volume becomes more positive from right to left
48
Why does the flow volume loop never get to zero?
Residual volume is greater than zero, so the loop never gets to zero (the x axis)
49
What is the max volume the lungs can hold on the flow volume loop (and real life)?
Total lung capacity
50
What lung volume represents the width of the flow volume loop (x axis)
Vital capacity
51
Factors that have NOT been shown to increase the risk of postoperative pulmonary complications for non thoracic surgery are? (3)
mild / moderate asthma arterial blood gas analysis pulmonary function testing
52
What are the is the best way to reverse anesthesia induced atelectasis?
Alveolar recruitment maneuvers (ARM's) This includes increasing peak airway pressure to 30 cm H20 for initial reopening, and increasing the PIP to 40 cm H20 for eight seconds which appears to reverse anesthesia-induced atelectasis almost completely
53
Does the application of PEEP reverse atelectasis?
Yes, but only partially
54
When should you apply PEEP to reverse atelectasis?
only after ARM have been used in an effort to prevent open airways from collapsing again, then apply PEEP
55
What can help prevent atelectasis that is not ARM or PEEP?
Mixing air with oxygen also helps prevent atelectasis
56
Lower than normal values for DLCO tell you what?
lower values correlate with a significant reduction in diffusing capacity
57
Does asthma affect tests of gas exchange such as DLCO?
NO, asthma affects airway diameter, but not alveolocapillary interface itself. This would affect tests of pulmonary mechanics (FEV1, MMF, etc), but not DLCO.
58
Explain the pathophysiology of chronic bronchitis?
Caused by inflammation and mucus production that reduces airway diameter
59
Explain the pathophysiology of emphysema?
caused by a reduction in the surface area of the alveolocapillary interface and loss of elastic recoil
60
Who are the pink puffers?
patient with emphysema
61
Who are the blue bloaters?
patient with chronic bronchitis
62
Tell me about the blood gases/labs of a person with chronic bronchitis?
Chronically low Pa02 They tend to retain CO2 They have polycythemia as their RBC have increased to try and compensate for the chronically low PaCO2
63
Tell me about the blood gases/labs of a person with emphysema?
Generally has a normal (or slightly reduced) Pa02. The PaCO2 is usually normal or decreased due to hyperventilation.
64
As a result of pulmonary hypertension the patient with chronic bronchitis may have this complication?
Cor Pulmonale
65
If a patient has Cor pulmonale then you want to avoid any anesthetic management that would increase PVR, this would include avoiding what?
hypoxia acidosis hypercarbia (any drug that causes respiratory depression can cause hypercarbia) hypothermia nitrous oxide vasoconstrictors conditions that increase SNS tone ketamine (maybe)
66
If you have a fixed PVR what can cause profound hypotension?
A decrease in SVR
67
Cor pulmonale is right sided heart failure that results from pulmonary hypertension. This creates a back pressure on the venous circulation that leads to?
jugular venous distension hepatomegaly lower extremity edema
68
Is increased PAOP consistent with RV failure?
NO, it is consistent with LV failure
69
If an area is ventilated but not perfused this increases what?
dead space
70
If an area is perfused but not ventilated this increases what?
shunt
71
If a patient has a pulmonary embolism will their EtCO2 increase or decrease?
Decrease (because it is diluted from a mixture of gas from perfused alveoli and alveoli lacking perfusion)
72
Why do you apply positive end-expiratory pressure for a patient who has just aspirated gastric contents?
Atelectasis increases pulmonary shunt, PEEP is indicated to reduce shunt (hypoxemia is the hallmark sign of aspiration pneumonitis)
73
What drug reduces free radical production, inhibits neutrophil chemotaxis, minimizes reperfusion injury, and improves outcomes in patients with aspiration pneumonitis?
Lidocaine
74
What is the best ventilatory strategy for restrictive lung diseases?
You want to reduce the risk of barotrauma, you accomplish this with small tidal volumes (6ml/kg IBW) and faster respiratory rate (14-18). Maintain PIP of less than 30 cm H20.
75
What are the five causes of hypoxemia?
``` high altitude hypoventilation diffusion defect V/Q mismatch Right to left shunt ```
76
High-altitude: A-a gradient? 02 helpful? Examples?
Normal Yes low barometric pressure
77
Hypoventilation: A-a gradient? 02 helpful? Examples?
normal yes low PA02, opioid overdose
78
Diffusion defect: A-a gradient? 02 helpful? Examples?
Increased Yes Pulmonary fibrosis,
79
V/Q mismatch: A-a gradient? 02 helpful? Examples?
increased yes dead space, shunt
80
Right to left shunt: A-a gradient? 02 helpful? Examples?
increased no (if shunt > apprx. 30%) VSD, TOF, Eisenmenger syndrome
81
Negative pressure pulmonary edema is an example of which type of restrictive lung dz?
acute intrinsic
82
example of chronic intrinsic restrictive lung dz?
pulmonary fibrosis
83
What percentage of cisatracurium and atracurium are metabolized by Hofmann elimination?
100% of Nimbex 33% atracurium
84
What effect does acidosis have on NMB?
Acidosis impairs the ability of the body's enzymatic systems to function properly. Acidosis perpetuates NMB and decreases the efficacy of anticholinesterase.
85
Hypoxemia during OLV is the result of what?
intrapulmonary shunt
86
Strategies for reversing hypoxemia during OLV?
Increase FI02 100% Check DLT position with FOB Apply CPAP 10 H20 to the non-dependent lung Apply PEEP 5-10 cm H20 to the dependent lung Ligate or clamp the pulmonary artery or the non-dependent lung (not always possible) Resume two-lung ventilation
87
EtCO2 capnography is typically a reliable indicator of Tracheal intubation but what times can it give you a false-negative result?
cardiac arrest severe bronchospasm complete ETT obstruction equipment malfunction