Pathophysiology Of Asthma

Front 1

what is the CNS mechanism of asthma? (3)

Back 1

1.allergen-induced immunological response
2.abnormal ANS regulation
3.imbalance b/t excitatory (bronchocontraction) and inhibitory (bronchodilation) neural input allowing mast cells to interact w/ ANS

Front 2

what are 4 airway characteristics of asthma?

Back 2

1. bronchial hyperreactivity
2. airway inflammation
3. hypertrophy of smooth muscle
4. reversible expiratory airflow obstruction

Front 3

is asthma obstructive or restrictive? -and- is asthma irreversible or reversible?

Back 3

expiratory obstruction of airflow; reversible

Front 4

age incidence in children & adults?

Back 4

children < 5; adults > 40, smokers w/ emphysema or chronic bronchitis

Front 5

what endothelium and cardiac disorders associated w/ asthma?

Back 5

subendothelial fibrosis & cardiac toxicity due to treatments

Front 6

explain allergen-induced immunologic rxn associated w/ asthma.

Back 6

1. antigen exposure
2. synthesis & secretion of
IgE antibodies
3. release of histamine,
interleukins, tumor necrosis factor,leukotrienes, prostaglandins, & platelet-activating factor from mast cells
4. airway inflammation, contraction, and hyperreactivit
5. eosinophils infiltrate airways hrs after allergen exposure
6. further release of chemical mediators

Front 7

what are the 3 classic manifestations of asthma?

Back 7

1. wheezing
2. coughing w/ copious yellow sputum
3. dyspnea

Front 8

reason for wheezing?

Back 8

turbulent airflow thru narrowed airways

Front 9

during wheezing, what is an omnious sign?

Back 9

it abruptly stops = complete obstruction of airways

Front 10

what could single monophasic wheezing that's consistent represent?

Back 10

focal airway obstruction (e.g. foreign body aspiration, neoplasm, etc.) and not asthma

Front 11

can coughing be the only symptom of asthma?

Back 11

yes

Front 12

what is dyspnea dependent on?

Back 12

obstruction of the airflow

Front 13

what other pathologic state can dyspnea mimic?

Back 13

angina pectoris

Front 14

what's the typcial functional exhaled volume of asthmatic patient?

Back 14

< 35% normal

Front 15

during severe attacks how much can FRC increase?

Back 15

1-2 liters

Front 16

what happens w/ TLC during asthma attack?

Back 16

usually remains normal

Front 17

how long can residual anomalies of PFTs persist following an attack? are symptoms present?

Back 17

several days after attack; no symptoms present

Front 18

are FVC increased or reduced? why?

Back 18

reduced; because airways close prematurely toward end of maximal expiration

Front 19

what do abg's reflect with mild asthma?

Back 19

normal abgs

Front 20

what do abg's reflect with moderate asthma? why?

Back 20

hypocarbia & respiratory alkalosis; because of initial hyperventilation

Front 21

what do abg's reflect with severe asthma? why?

Back 21

hypercarbia; common cause is muscle fatigue

Front 22

what happens with your v/q & o2 in severe asthma?

Back 22

severe v/q mismatch and decreased o2

Front 23

name 3 diagnostic tests for asthma.

Back 23

cxr, ekg, & bronchodilator responsiveness

Front 24

what does cxr show w/ asthma?

Back 24

hyperinflation of lungs

Front 25

what does ekg show w/ asthma?

Back 25

right heart failure & ventricular irritability during acute attack

Front 26

what is benefit of bronchodilator responsiveness test?

Back 26

provides supportive evidence when asthma suspected

Front 27

what does bronchodilator responsiveness test show w/ asthma?

Back 27

=/> 15% increase in airflow

Front 28

why would you get false (+) or false (-) w/ bronchodilator responsiveness test?

Back 28

because of the episodic nature of the disease

Front 29

name 10 differential dx for asthma.

Back 29

1. tracheobronchitis
2. sarcoidosis
3. RA
4. CA
5. croup & other upper airway diseases
6. hx of intubation
7. hx of trauma
8. hx of surgery
9. chf
10. pulmonary edema

Front 30

name 5 different types of asthma.

Back 30

1. allergen-induced
2. excercise-induced
3. aspirin-induced
4. occupational
5. infectious

Front 31

Which asthma type is this?
1. IgE mediated
2. most common
3. allergic rhinitis or dermatitis (may be present)
4. genetic
5. release of mediators

Back 31

allergen induced asthma

Front 32

what's the physiology behind exercised-induced asthma?

Back 32

changes in heat & water in tracheobrachial tree during humidification of large volumes of air

Front 33

what's another name for exercised-induced asthma?

Back 33

"thermal induced-asthma"

Front 34

who most commonly suffers from exercise-induced asthma? and why?

Back 34

children & young adults b/c of high levels of physical activity

Front 35

what drugs should sufferers of aspirin-induced asthma stay away from?

Back 35

ASA, NSAIDS (especially tordal)

Front 36

what physical feature is often seen with suffers of aspirin-induced asthma?

Back 36

nasal polyps

Front 37

what's the underlying cause of aspirin-induced asthma?

Back 37

1. blockage of cyclooxygenase-mediated conversion of arachidonic acid to prostaglandins

2. formation of leukotrienes

Front 38

how many agents have been noted for occupational asthma?

Back 38

250 different agents

Front 39

what are the 2 types of occupational asthma?

Back 39

IgE dependent and non-IgE dependent

Front 40

what's the difference b/t the 2 types of occupational asthma?

Back 40

IgE dependent: longer latency periods b/t exposure & symptoms

non-IgE: brief intervals b/t exposure & symptoms

Front 41

what are 3 common agents that cause occupational asthma?

Back 41

chlorine
ammonia
latex

Front 42

what's the underlying cause of infectious asthma?

Back 42

acute inflammatory disease secondary to viruses, bacteria, or mycoplasma organisms

Front 43

what were the past therapies for the prevention and control of asthma?

Back 43

bronchodilators

Front 44

what was the problem w/ using bronchodilators for prevention and control of asthma?

Back 44

mask underlying inflammatory process by relieving symptoms but allowing continued exposure to allergens

Front 45

what happens initially w/ ABGs after tx w/ bronchodilators? and what's the cause?

Back 45

PaO2 initially decreases

2nd to relief of vasoconstriction in poorly ventilated areas

Front 46

why is the initially drop in PaO2 w/ bronchodilator tx tolerated?

Back 46

due to greatly enhanced airflow

Front 47

what is the current preferred first line tx for asthma?

Back 47

corticosteriods

Front 48

what caused the switch from bronchodilators to steriods for prevention and control of asthma?

Back 48

asthma now recongnized as chronic inflammatory process

Front 49

why do bronchodilators work for asthma?

Back 49

beta-agonist causing dilation of bronchial smooth muscles

Front 50

what are 2 current uses for bronchodilators?

Back 50

1. prevention of exercise-induced asthma

2. relief of symptoms when anti-inflammatory therapy is insufficient

Front 51

what should happen to FEV after drug treatment for asthma?

Back 51

FEV should return to 50% normal

Front 52

name 6 drug therapies for asthma.

Back 52

1. anti-inflammatories
2. cromolyn
3. leukotriene inhibitors
4. bronchodilators
5. anticholinergics
6. methylxanthines

Front 53

what drug therapy is most effective at controlling chronic symptoms of asthma?

Back 53

corticosteriods

Front 54

via which route are corticosteriods typically administered?

Back 54

inhaled

Front 55

how long does it generally take for inhaled corticosteriods to take effect?

Back 55

several months after tx airway hyperresponsiveness is reduced

Front 56

what drug regimen is associated w/ decreased risk of death from asthma?

Back 56

regular low-dose inhaled steriods

Front 57

name some drugs w/in the inhaled steriod class for tx of asthma.

Back 57

beclomethasone
budesonide
fluisolide
fluticasone
triamcinolone

Front 58

are inhaled steriods water soluble or lipid soluable? and what's the advantage of this property?

Back 58

highly lipophilic

allows for rapid entery into airway cells

Front 59

what's the mechanism of action of inhaled steriods?

Back 59

inhibts gene transcription for cytokines during asthmatic inflammation

Front 60

how much of the inhaled steriod is swallowed? and is this a problem?

Back 60

most (~80%)

no, b/c the drug is still systemically absorbed following the first pass effect

Front 61

what are 4 side effects of inhaled corticosteriods?

Back 61

1. hoarseness
2. candidiasis (elderly)
3. glossitis
4. pharyngitis

Front 62

do inhaled steriods effect metabolism? or pituitary-adrenal function?

Back 62

no evidence

little to no effect even at high doses

Front 63

how does cromolyn work?

Back 63

inhibits release of chemical mediators from mast cells

Front 64

what the disadvantage of cromolyn?

Back 64

not effective once bronchospasm is present

Front 65

in relation to anti-inflammatory therapy: how are leukotriene inhibitors used?

Back 65

with or substituted for anti-inflammatory therapy

Front 66

which types of asthma do leukotrienes play a role in?

Back 66

aspirin induced
excercise induced
allergen induced

Front 67

how do bronchodilators work?

Back 67

a. stimulate beta 2 receptors
b. increase cAMP
c. tracheobronchial smooth muscle relaxation

Front 68

r/t steriod therapy: how are bronchodilators typically used?

Back 68

in combination w/ steriods

Front 69

which bronchodilator is most selective beta 2 agonist?

Back 69

albuterol

Front 70

name 5 side effects of bronchodilators.

Back 70

1. SNS stimualtion
2. tachycardia
3. cardiac dysrhythmias
4. intracellular shift of K
(hypokalemia)
5. down regulation

Front 71

how do anticholinergics work in the tx of asthma?

Back 71

blocks muscarinic receptors in airway smooth muscle decreasing vagal tone

Front 72

which respiratory disease process are anticholinergics more effective in ?

Back 72

COPD

Front 73

give an example of an anticholinergic for tx of asthma.

Back 73

ipratropium (Isuprel)

Front 74

give 2 examples of methylxanthines for tx of asthma.

Back 74

aminophylline
theophylline

Front 75

what are the potency level effects of methylxanthines control?

Back 75

modest anti-inflam

bronchodilator effects < beta 2 agonist

Front 76

what measurements are important during tx w/ methylxanthines?

Back 76

blood therapeutic levels

Front 77

what is status asthmaticus?

Back 77

un-resolved life-threatening bronchospasm

Front 78

what are 4 effective tx of status asthmaticus?

Back 78

1. repeated doses of inhaled beta 2 agonists

2. iv corticosteriods

3. supplemental oxygen to keep sat > 95%

4. broad-spectrum antibiotics

Front 79

give 2 examples of IV corticosteriods.

Back 79

cortisol
methylprednisolone

Front 80

what ABG parameter warrants tracheal intubation and mechanical ventilation during status asthmaticus?

Back 80

PaCO2 > 50 due to resp fatigue despite aggressive treatment

Front 81

are low or high peak pressure needed for intubated status asthmaticus patients? why?

Back 81

high peak pressures

in order to deliver adequate TV despite bronchocontriction

Front 82

what's the disadvantage of OR vents when managing status asthmaticus patients?

Back 82

too much compressible volume wasted on circuit to deliver adequate TV w/ such high pressure

Front 83

what's the benefit of high gas flows w/ status asthmaticus patients?

Back 83

shorter inspiratory time

greater exhalation time

lower PEEP

Front 84

is hypercarbia positive or negative w/ status asthmaticus patients? why?

Back 84

positive

can reduce barotrauma

Front 85

when is general anesthesia required for production of bronchodilation? and what inhalational agents are beneficial?

Back 85

very ill patients

halothane, enflurane, isoflurane

Front 86

name 6 preop evaluation goals for anesthesia mgmt of asthma patients.

Back 86

1. plan that prevents/blunts obstruction of airflow
2. h&p
3. understand: disease & effectiveness of tx
4. listen to pt's lungs
5. PFT (before & after bronchodilator therapy), ABGs, CXR

Front 87

what 5 drug types may be given to an asthma patient preop? and what concerns are present?

Back 87

1. opioids (watch
ventilatory effects)
2. anticholinergics (watch
for increased viscosity
of secretions)
3. H2 receptor antagonists
(watch for
bronchoconstriction due
to blocked
bronchodilating effects
of H2)
4. bronchodilators (should
be continued up to
induction)
5. corticosteriods
(supplementation may be
needed for larger
surgeries, esp w/
possibility of adrenal
suppresion by drugs used
to tx asthma)

Front 88

what's the effect of ASA, NSAIDS, etc during postoperative period?

Back 88

ASA, NSAIDS may produce adverse effects (asthma attack) in pts w/ asthma so use w/ caution

Front 89

what's the #1 goal of induction and maintenance for asthma pts?

Back 89

depress airway reflexes w/ anesthetic drugs to avoid bronchoconstriction in response to mechanical stimulation

Front 90

name one factor that would precipitate bronchospasms during intubation.

Back 90

inadequate depth of anesthesia to suppress airway reflexes

Front 91

what is an alternative to intubating? why?

Back 91

regional anesthesia

will avoid intubation & instrumentation of airway

Front 92

what's the + or - benefits of propofol w/ asthma pts?

Back 92

+ = bronchodilating effects

- = use only if hemodynamics are stable

Front 93

what's the + or - benefits of ketamine w/ asthma pts?

Back 93

+ = sympathomimetic effects for those actively wheezing

- = do not use in increased ICP, etc.

Front 94

what's the + or - benefits of thiopental w/ asthma pts?

Back 94

+ = doesn't cause bronchospasms

- = doesn't suppress airway reflexes enough for instrumentation which may acutally trigger bronchospasms

Front 95

what is metabisulfates and their significance to asthma pts?

Back 95

preservative found in generic propofol

may cause bronchospasm

Front 96

which volatile gas is the most effective bronchodilator? and at what MAC?

Back 96

halothane

MAC < 1.7

Front 97

which 2 volatile agents are less pungent? which 2 are more pungent? and why is this important?

Back 97

halothane & sevoflurane < isoflurane & desflurane

less pungent = less coughing and bronchospasms

Front 98

what's the importance of lidocaine for induction in asthmatics? and when should it be given?

Back 98

blunts airway relexes

1-3 minutes prior to DVL & intubation

Front 99

why is albuterol so important during intubation/maintenance phase?

Back 99

it's most effective at blunting airway responsiveness to intubation

Front 100

which NMBA is best for asthma pts?

Back 100

anyone that is less likely to cause histamine release

Front 101

what is the effect of atricurium on histamine release & the airway of asthma pts?

Back 101

large increases in histamine release

severe broncospasms following administration

Front 102

what is the effect of sux on histamine release & the airway of asthma pts?

Back 102

mild increases in histamine

there's been no evidence of increased airway resistance w/ sux

Front 103

what effect can anticholinesterase drugs have on the airway of asthma pts? and what's the underlying cause?

Back 103

bronchospasms of smooth muscles of airway

due to stimulation of postganglionic cholinergic receptors in airway smooth muscles

Front 104

what blunts the effects of anticholinesterase drugs on the smooth muscles of the airway?

Back 104

anticholinergic drugs given w/ them during reversal of NMBAs

Front 105

name 5 facts for ventilatory managments during surgery on asthma pts.

Back 105

1. slow inspiratory flow
(for optimal V/Q ratios)
2. allow sufficient time for
exhalation (to prevent
air trapping)
3. avoid PEEP (it can impair
adeq exhalation along w/
narrowed airways)
4. humidification (to reduce
transmucosal heat loss
that can trigger
bronchospasm)
5. maintain hydration w/
liberal IV fluids (aid in
expulsion of secretions)

Front 106

what are 2 possible extubation plans for asthma pts?

Back 106

1. deep extubation (b/c airway reflexes are still suppressed)

2. awake extubation (but continuous lidocaine 1-3 mg/kg/hr to minimized airway stimulation may be needed)

Front 107

what's important to note regarding the admin of ASA, NSAIDS, etc in asthma pts postop?

Back 107

use caution b/c adverse asthma attacks are possible

Front 108

name 4 ways to manage intraop bronchospasms in asthma pts.

Back 108

1. bronchospasm NOT due to
acute asthma exacerbation
will respond to deepening
of anesthesia with
volatile agents OR NMBAs
2. bronchospasm due to acute
asthma exacerbation will
respond to deepening of
anesthesia with volatile
agents but NOT NMBAs
3. beta 2 agonists, i.e.
albuterol, thru T-
connector (for
bronchospasms after
deepened anesthesia)
4. corticosteriod therapy
(for bronchospasms after
deepening of anesthesia &
bronchodilators)

Front 109

does albuterol have a synergistic or additive effect w/ volatile agents?

Back 109

additive

Front 110

what's the onset of therapeutic action for corticosteriod theraphy?

Back 110

at least 3-4 hrs after administration

Front 111

what is the conflict regarding emergency surgery and asthma pts?

Back 111

conflict b/t airway protection from aspiration & production of bronchospasms w/ awake intubation

Front 112

compare the use of bronchodilator therapy and regional anesthesia for EMERGENCY surgery in asthma pts.

Back 112

bronchodilator therapy - insufficient time for benefit

regional anesthesia - may be best option if possible for superficial or extremity injuries