Respiratory Flashcards
1
Q
What are the two conformations of hemoglobin?
A
T-State: Low oxygen affinity
R-State: High oxygen affinity
2
Q
What stabilizes hemoglobin into the T-state?
A
- H+
- CO2
- 2,3-DPG
*Due to products of processes occurring in the tissues → in the tissues we want to offload oxygen (low affinity)
3
Q
What stabilizes hemoglobin in the R-state?
A
- O2
2. CO
4
Q
What happens in carbon monoxide poisoning?
A
The R-form of hemoglobin is stabilized. CO binds to hemoglobin with a higher affinity than oxygen
5
Q
How does the O2-hemoglobin curve shift in acidemia
A
Right
6
Q
How does the O2-hemoglobin curve shift with increased CO2 concentrations?
A
Right
7
Q
How does the O2-hemoglobin curve shift in decreased temperatures?
A
Left
8
Q
How does the O2-hemoglobin curve shift in increased 2,3-DPG?
A
Right
9
Q
What is the Bohr effect?
A
The effect of CO2 and H+ on the affinity of hemoglobin for O2
- Increased CO2 and H+ → decreases affinity/promotes offloading
- Decreasing CO2 and H+ → increases affinity/enhances loading
10
Q
How does the O2-hemoglobin curve shift at the pulmonary capillary bed?
A
Left
- Decreased p50
- Increased O2 affinity and uptake
11
Q
What forms does CO2 exist in the blood?
A
- HCO3 - 70%
- Hemoglobin - 23%
- Dissolved in plasma (pCO2) - 7%
12
Q
How does CO2 interact with the red blood cells?
A
It is brought into the red blood cell and interacts with carbonic anhydrase → ultimately results in the dissociation of carbonic acid into H+ and HCO3 → HCO3 diffuses out of the red blood cell and Cl shifts in (Chloride shift)
13
Q
What is the Haldane effect?
A
O2 + hemoglobin = stronger acid
- Less tendency to combine with CO2 to form carbaminohemoglobin
- Release an excess of H2 ions
14
Q
What is the difference between the Bohr and Haldane effects?
A
- Bohr → increase in CO2 in blood causes O2 to be displaced from oxygen (tissues)
- Haldane → binding of O2 with hemoglobin causes CO2 to be displaced from the hemoglobin (lungs)
15
Q
What determines the excretion of CO2?
A
Minute ventilation (TV x RR)
16
Q
What are the regulators of respiration (what and where)?
A
- Central chemoreceptors - CO2
- 2/3 of CO2 regulation (slow) - Peripheral chemoreceptors - CO2
- 1/3 of CO2 regulation (fast)
17
Q
Where are the peripheral chemoreceptors?
A
Aortic and carotid bodies
18
Q
How do peripheral chemoreceptors detect decreases in PO2? What happens when decreased PO2 detected?
A
Glomus cells → O2 sensitive K channels
Decreased O2 → K efflux → calcium influx → depolarization → dopamine release → respiratory stimulation via cranial nerve IX
19
Q
Why does CO2 have a more potent effect in stimulating the central chemoreceptor neurons than hydrogen ions?
A
The blood brain barrier is not very permeable to hydrogen ions, but CO2 passes easily through the BBB
20
Q
Where are the central chemoreceptors located?
A
Chemosensitive area bilaterally of the medulla oblongata
21
Q
How do the central chemoreceptors work?
A
Excited more easily by hydrogen ions → problem because H does not easily pass the BBB
CO2 passes through the BBB and interacts with carbonic anhydrase to form H+ and HCO2 → the H+ then interacts with the central chemoreceptor
22
Q
Where is the respiratory center located?
A
Bilaterally in the medulla oblongata and the pons
23
Q
What are the different groups in the respiratory center? What do they control?
A
- Dorsal respiratory group → Inspiration
- Ventral respiratory group → Expiration (and inspiration), inactive during normal quiet respiration
- Pneumotaxic center → rate and depth of breathing, the inspiratory “off-switch”
24
Q
What disease is associated with dysfunctional cilia?
A
Primary cilia dyskinesia (PCD)
25
What breed is predisposed to primary cilia dyskinesia?
Bichon Frise
*Old English Sheepdogs, Alaskan malamutes and English pointers can also be affected
26
What are the clinical signs associated with primary cilia dyskinesia?
1. Nasal discharge
2. Recurrent respiratory infections
3. Male infertility
4. Hydrocephalus
5. Sinus inversus
27
What is the cause of primary cilia dyskinesia?
Mutation in microtubule conformations
28
Parasympathetic ACh causes what effect in the lung?
BronchoCONSTRICTION
29
Sympathetic Epi/Norepi causes what effect in the lung? Via which receptor?
BronchoDILATION
| - B2 adrenergic receptors
30
What is the most common form of canine fungal rhinitis? How is this treated?
Aspergillus
Tx: Clotrimazole infusion
31
What is the most common form of feline fungal rhinitis? How is this treated
Cryptococcus
Tx: Fluconazole
32
What compose the conducting airways?
Trachea and bronchi
*Anatomic dead space
33
What are the basal cells in the respiratory epithelium?
1. Lie underneath the columnar cells
2. Stem cell producing new epithelial and goblet cells
3. ABSENT in bronchioles and beyond
34
What cells secrete secrete surfactant?
Type II alveolar epithelial cell (granular pneumocytes)
35
Which alveolar epithelial cells are most abundant?
Type 1 - 95%
| Type 2 - 5%
36
What are the roles of type 1 alveolar epithelial cells (pneumocytes)
1. Line alveoli
2. Function in gas exchange
3. Do not divide in vivo
*Exposed to the highest concentration of oxygen - can. have oxygen toxicity damage
37
What are the roles of type 2 alveolar epithelial cells (pneumocytes)
1. Stem cells from which type 1 cells arise
2. No gas exchange
3. Produces/Stores surfactant in the cytoplasm
4. Resistant to oxygen toxicity damage
38
What is surfactant composed of?
1. 80% phospholipids
2. 5-10% neutral lipids
3. 8-10% proteins
39
What muscle(s) plays a role in the process of inspiration?
1. Diaphragm → contracts and flattens, causes intrapleural space to become more negative
2. External intercostals → make diaphragm contraction more efficient, little role at rest, greater role during exercise
40
What muscle(s) plays a role in the process of expiration?
* Typically a passive process*
1. Abdominal muscles push diaphragm up → increase the intrapleural pressure
2. Internal intercostals → oppose action of external intercostals, pull ribcage down and in
3. Accessory muscles → laryngeal muscles, act as "breaks"
41
What components determine lung compliance?
1. Elastic forces of the lung → 1/3, composed of elastin and collagen fibers
2. Elastic forces caused by surface tension of the fluid that lines the inside of the alveoli → 2/3, surfactant
42
What decreases lung compliance?
1. High lung volume
2. Surfactant deficiency
3. Pulmonary edema
4. Atelectasis or alveolar collapse
5. Pulmonary fibrosis
6. Smooth muscle constriction in the small airways (asthma)
43
What increases lung compliance?
1. Age
2. Emphysema
3. Body size
44
Which breed is predisposed to idiopathic pulmonary fibrosis?
Westies!
45
What is tidal volume?
Volume of air inspired or expired with each normal breath
10-15 ml/kg
46
What is the inspiratory reserve volume?
The extra volume of air that can be inspired OVER the normal tidal volume
47
What is the inspiratory capacity?
Tidal volume + inspiratory reserve volume
The total amount of air that an individual can breathe in
48
What is the expiratory reserve volume?
The extra volume of air that can be expelled by an active expiratory effort AFTER passive expiration
49
What is the the residual volume?
The volume of air remaining in the lungs after the most forceful expiration
50
What is the functional residual capacity?
Expiratory reserve volume + residual reserve volume
The amount of air that remains in the lungs at the end of normal expiration
51
What is the vital capacity?
Tidal volume + inspiratory reserve volume + expiratory reserve volume
The maximum amount of air an individual can expel from the lungs after filling the lungs to the maximum extent and then expiring to a maximum extent
52
What is the total lung capacity?
Vital capacity + residual volume
The maximum amount of air the lungs can be expanded with the greatest amount of effort
53
What factors affect diffusion in the lung?
1. Thickness of membranes
2. Surface area
3. Diffusion coefficient of gas
4. Partial pressure difference
54
What happens to the blood vessel if the concentration of O2 in an alveoli decreases?
1. Adjacent blood vessels constrict → increase vascular resistance
2. Distributes blood flow to where the lungs are better aerated
55
What occurs to V/Q in the following scenarios?
1. Without ventilation
2. Without perfusion
1. V/Q = 0
| 2. V/Q = infinity
56
What diseases can lead to a low V/Q (poor ventilation, decreased PaO2)
1. Chronic bronchitis
2. Asthma
3. Pulmonary edema
*Ventral lungs have slightly lower V/Q
57
What diseases can lead to a high V/Q (poor perfusion, increased PaCO2)
1. Pulmonary thromboembolism
| * Dorsal lungs have high V/Q
58
Which intestinal worms have pulmonary migration?
1. Ancylostoma
| 2. Toxocara
59
How do you treat intestinal worm associated pulmonary disease?
1. Glucocorticoids
| 2. Fenbendazole - 2 doses, 2 weeks apart
60
Lung worms are (easy/difficult) to diagnose based on fecal flotation or sedimentation. Why?
1. Difficult
2. Intermittent shedding
*Treat with empiric fenbendazole if suspected
61
What is the most common feline lungworm? Where (geographically) is it most prevalent?
1. Aelurostrongylus
| 2. Southern US
62
Where do Aelurostrongylus reside in the lungs?
Terminal bronchioles and alveoli
63
How are Aelurostrongylus transmitted?
1. Fecal-oral transmission
* They are coughed up and then passed in the feces
2. Eating encysted larvae in the tissue of mice and birds
64
What are the clinical signs associated with Aelurostrongylus infection?
1. Mild
2. Severe
1. Typically asymptomatic - Hard to differentiate from feline lower airway disease!
2. Severe eosinophilic bronchopneumonia with bronchointerstitial to alveolar infiltrates
65
How is Aelurostrongylus diagnosed?
BAL or Baerman
66
How do you treat an Aelurostrongylus infection?
1. Fenbendazole or macrocyclic lactone
2. Anti-inflammatory glucocorticoids
3. Bronchodilators
67
What are the lung flukes? Where are they present geographically?
1. Paragonimus kellicoti and westermani
| 2. Great Lakes, midwest, and South
68
What do paragonimus sp. cause in the lungs of dogs and cats?
Cysts
69
What clinical signs are common with paragonimus sp.
1. Eosinophilic pleurites and cough (common)
2. Nodules, bullae, and atelectasis can occur in the RIGHT MIDDLE LUNG LOBE
3. Hemoptysis and pneumothorax can occur when adults emerge
70
How are paragonimus sp. diagnosed?
1. Ova often present on BAL
| 2. Intermittently present on sedimentation
71
How are animals infected with paragonimus sp.?
Eating raw crabs or crayfish
72
How are paragonimus sp. treated?
Fenbendazole or praziquantel
73
What are the canine lungworms?
1. Filaroides hirthi and milksi
| 2. Crenosoma vulpis
74
What population acquires filaroides spp.?
Research colonies
75
Adult filaroides live in which part of the lung?
Terminal bronchioles and alveoli
76
How are filaroides sp. treated?
Fenbendazole or ivermectin
77
Where is crenosoma vulpis located geographically?
1. Northeastern US
| 2. Canada
78
Where are crenosoma vulpis adults located in the lung?
Terminal bronchioles and alveoli
79
How are crenosoma vulpis treated?
Fenbendazole or macrocyclic lactones
80
Where is angiostrongylus vasorum located geographically?
1. Canada
2. Europe
*"French heart worm"
81
Bacterial pneumonia is most commonly secondary to what?
1. Immune suppression
| 2. Aspiration
82
What are empiric therapy options for bacterial pneumonia?
1. Potentiated penicillin or 3rd gen cephalosporin
2. Fluoroquinolone
*Used in patients with disease too severe to wait for culture results
83
Cough suppressants are (indicated/contraindicated) in bacterial pneumonia
contraindicated
84
What are causes of fungal pneumonia?
1. Histoplasmosis
2. Blastomycosis
3. Coccidiomycosis
4. Aspergillosis
85
How is fungal pneumonia diagnosed?
1. Urine antigen testing
| 2*. Cytology is possible for pulmonary aspergillosis
86
How is fungal pneumonia treated?
1. Histo, blasto, cocci: Itraconazole
2. Asper: Itraconazole (pulmonary) or voriconazole (systemic)
*Pulmonary aspergillosis may require a lung lobectomy
87
What can cause pulmonary edema (general)?
1. Increased hydrostatic pressure
2. Decreased oncotic pressure
3. Failure of lymphatic drainage
4. Increased vascular permeability
88
What is the mechanism behind cardiogenic pulmonary edema?
Increased hydrostatic pressure from heart failure related fluid overload
89
What kind of fluid is associated with heart failure?
Modified transudate with low protein
90
How is cardiogenic pulmonary edema treated?
1. Diuretics
2. Reduction in after load
3. +/- positive inotropes
91
What is the mechanism behind non-cardiogenic pulmonary edema?
Vascular permeability increases due to lung injury - the fluid is relatively protein rich
92
What are causes of non-cardiogenic pulmonary edema
1. Neurogenic
2. Respiratory obstruction (lar par, brachycephalic airway, and pneumothorax)
3. Acute lung injury or ARDS secondary to severe systemic inflammation
4. Direct pulmonary injury
5. Severe hypoalbuminemia
93
What kind of heart rhythm is associated with:
1. Cardiogenic pulmonary edema
2. Non-cardiogenic pulmonary edema
1. Sinus tachycardia
| 2. High vagal tone and sinus arrhythmia
94
What is a finding on the CBCs of dogs with idiopathic eosinophilic pneumonia/bronchitis?
1. 50% have eosinophilia
95
How is idiopathic eosinophilic pneumonia treated in the dog?
Steroids
96
What is the prognosis of eosinophilic pneumonia/bronchitis?
Excellent
97
What causes lipid pneumonia?
Accumulation of lipid in the airways - often secondary to administration of petroleum medications used for the treatment of hairballs or constipation
98
Which secondary condition is often associated with pulmonary fibrosis? How is this treated?
1. Pulmonary hypertension
| 2. Sildenafil
99
What is the most common cause of pulmonary contusions?
1. Hit by car or bite wound
100
What is the most common (non-traumatic) cause of pulmonary contusions?
Rodenticide toxicity
101
What are causes of pulmonary hypertension?
1. Primary (Idiopathic)
2. Left heart failure
3. Pulmonary disease or hypoxia
4. Thromboembolic disease
5. Compressive mass lesions
102
How does chronic hypoxia cause pulmonary hypertension?
Causes inappropriate vasoconstriction
*Altitude, pulmonary fibrosis, chronic bronchitis, neoplasia
103
How is pulmonary hypertension diagnosed?
Tricuspid regurgitation velocity > 2.8
*Indicates pressure difference of >31
104
How is pulmonary hypertension treated? What is the mechanism behind this therapy?
Sildenafil
*Delays breakdown of cGMP → prolongs the vasodilatory effects of NO
105
What test has a high sensitivity for pulmonary thromboembolism?
1. Elevated D-dimer
106
What are the most common causes of noninfectious tracheitis?
1. Secondary - tracheal collapse, cardiac enlargement, oropharyngeal disease, prolonged barking
107
What is the treatment for noninfectious tracheitis?
1. Bronchodilators - theophylline or terbutaline
| 2. Cough suppressants - dextromethorphan, hydrocodone, butorphanol
108
What is the most common cause of canine respiratory disease complex?
1. Bordetella bronchiseptica with either canine parainfluenza or canine adenovirus
109
Where does osleuris osleuri reside in the dog?
*Tracheal worm - also called filaroides osleuri
| Lives in the proximal trachea and large bronchi
110
What kind of lesions does osleuris osleuri form in the dog?
Semi-circular mass like nodules along the inside of the trachea as they mature
111
What age of dog is osleuris osleuri infection most common?
Young dogs (<2 year)
112
How is osleuris osleuri treated?
1. Fenbendazole
| 2. Surgical removal of large nodules if breathing is inhibited
113
What is the underlying cause of tracheal hypoplasia? What kind of breed is this most common?
1. Congenital
| 2. Brachycephalic breeds
114
How is tracheal hypoplasia diagnosed?
Radiographs - tracheal lumen is less than 2x the width of the third rib
115
What is the prognosis for dogs with tracheal hypoplasia?
Guarded
116
What is a common sequelae to tracheal hypoplasia?
Bronchopneumonia
117
What else should you look for in dogs with tracheal hypoplasia?
Other congenital defects - e.g. cardiac defects
118
What are the causes of tracheal stenosis?
1. Congenital
| 2. Trauma/Tracheostomy
119
What is the underlying cause of congenital tracheal stenosis?
Absence of tracheal rings which leads to focal stenotic regions
120
Which direction is collapsing trachea most common?
Dorsoventral
121
What is the underlying cause of tracheal collapse?
1. Progressive cartilage destruction
| - Cartilagenous rings are hypocellular and have decreased glycosaminoglycans and glycoprotein levels
122
How does inspiratory/expiratory effort help distinguish location of collapsing trachea lesions?
1. Inspiratory effort → extrathoracic lesion
| 2. Expiratory effort → intrathoracic lesion
123
What is the definition of canine chronic bronchitis?
Inflammatory condition of the upper airway lasting for >2 months
124
What is the underlying type of inflammation in canine chronic bronchitis?
Neutrophilic or eosinophilic inflammation
| * Also have thickened smooth muscle layer and fibrosis/scarring of the lamina propria
125
Canine chronic bronchitis is most commonly seen in (small/large) breed dogs
Small
126
How is canine chronic bronchitis treated?
1. anti-inflammatory glucocorticoids
2. Bronchodilators
3. Cough suppressants at night
127
What is bronchiectasis?
Chronic changes to the structure of the airways due to destruction of connective tissue and muscle → leads to permanent dilation and destruction of mucociliary conduction
128
What causes bronchiectasis?
Secondary to:
1. Chronic bronchitis
2. Primary ciliary dyskinesia
3. Chronic exposure to inhaled irritants
129
How is bronchiectasis diagnosed?
Imaging (CT is best) → lack of appropriate taper at the periphery
130
How is bronchiectasis treated?
1. Often need chronic antibiotics due to damaged mucociliary apparatus
2. Nebulization/Coupage
3. Management of underlying chronic bronchitis (glucocorticoids)
4. AVOID antitussive medications
131
What type of hypersensitivity reaction is feline bronchial disease?
Type 1 due to inhaled allergens
132
Pneumomediastinum (does/does not) occur secondary to pneumothorax
Does not
133
Pneumothorax, subcutaneous emphysema, or pneumoretroperitoneum (can/can not) occur secondary to pneumomediastinum
Can
134
Non-neoplastic mediastinal masses are typically ____ in origin
Infectious
135
What clinical signs are associated with a space occupying mediastinal mass?
1. Horners syndrome
2. Edema of the head, neck, and forelimbs
3. Dyspnea or dysphagia
136
Flail chest (does/does not) cause hypoxemia
Does not
| *Associated contusions can though
137
What is the most common cause of a pyothorax in the dog? The cat?
1. Grass awns
| 2. Bite wounds
138
What % of patients with a pyothorax will have a fever?
30-50%
139
What kind of infection do dogs with pyothorax have? Cats?
1. Actinomyces or nocardia
* Nocardia is partially acid-fast staining
2. Pasturella
140
What is the treatment for pyothorax?
1. Medical management → Abx for 4-5 weeks (be sure to include anaerobic coverage)
2. Surgical management → in cases with a mass, foreign body, abscess, or lung lobe torsion. Also in cases where medical management fails to improve patient or if they worsen after 72 hours
141
What is the most common cause of chylothorax?
Idiopathic
142
What are the characteristics of the fluid in dogs with chylothorax?
1. Modified transudate or exudate
2. Small lymphocytes predominate
3. Pleural fluid triglycerides are higher than serum triglycerides
143
How is chylothorax treated?
1. Medical management - rutin, may take weeks to resolve
| 2. Surgical - ligate the thoracic duct
144
What is the success rate of thoracic duct ligation in the treatment of chylothorax?
30%
145
What % of idiopathic thoracic effusions resolve spontaneously?
40%
146
What % of traumatic chest injuries in dogs result in a pneumothorax?
50%
147
What is the major site of airway resistance?
Medium sized bronchi
| *Small airways do not have the largest resistance due to their parallel arrangement
148
Asthma
1. Obstructive/Restrictive Disease
2. Inspiration/Expiration Impaired
1. Obstructive
| 2. Expiration
149
Fibrosis
1. Obstructive/Restrictive Disease
2. Inspiration/Expiration Impaired
1. Restrictive
| 2. Inspiration
150
What is Fick's Law of Diffusion
Diffusion = (Pressure gradient x Surface Area x Solubility)/(Distance x MW^(1/2))
151
What is perfusion limited gas exchange?
* Illustrated by O2
- The gas equilibrates early along the length of the pulmonary capillary - the partial pressure of the gas in arterial blood becomes equal to the partial pressure in the alveolar air
- Diffusion of the gas can only be increased with increased blood flow
152
What is diffusion limited gas exchange?
* Illustrated by CO2
- The gas does not equilibrate by the time the blood reaches the end of the pulmonary capillary
- The partial pressure of the gas between alveolar air and pulmonary capillary blood is maintained - diffusion continues as long as the partial pressure gradient is maintained
153
What are the causes of hypoxemia? Which will not respond to oxygen therapy?
1. Hypoventilation (Decreased PAO2)
2. Diffusion Defect
3. V/Q Mismatch
4. Shunts
5. Low FiO2
*Shunt will not respond to 100% O2
154
What are the causes for hypoxia?
*Decreased O2 delivery to tissues
1. Decreased cardiac output
2. Hypoxemia
3. Anemia
4. CO poisoning
5. Cyanide poisoning
155
In what zone of the lung is blood flow the lowest? The highest?
1. Zone 1
| 2. Zone 3
156
How is hypoxia different in the lung compared to other tissues?
Lung hypoxia (alveolar) causes vasoconstriction to send blood to better aerated areas of the lung whereas it causes vasodilation in other tissues
157
What part of the lung has the highest ventilation?
1. The base
2. The apex is the lowest
*Due to the effects of gravity
158
Where is the V/Q ratio the highest? The lowest?
1. The apex
| 2. The base
159
PO2 and PCO2 are (highest/lowest) in which part of the lung?
1. Apex: PO2 is highest, PCO2 is lowest
- Due to higher V/Q, gas exchange is more efficient
2. Base: PO2 is lowest, PCO2 is highest
- Due to lower V/Q, gas exchange is less efficient
160
How are PO2 and PCO2 affected in airway obstruction?
V/Q = 0
| Will approach their values in mixed venous blood
161
How are PO2 and PCO2 affected in pulmonary embolism?
V/Q = infinity
| Will approach their values in inspired air
162
The dorsal respiratory group controls (inspiration/expiration)
Inspiration
| Generates a rhythm for breathing
163
The ventral respiratory group controls (inspiration/expiration)
Expiration
| *Not active during normal breathing
164
The pneumotaxic center (inhibits/stimulates) inspiration
inhibits
165
How are the following affected by high altitude?
1. Alveolar and arterial PO2
2. Acid/Base status
3. [Hemoglobin]
4. [2,3 DPG]
5. Right Ventricle
1. Alveolar PO2 is decreased, so arterial PO2 is also decreased
2. Respiratory alkalosis (hypoxemia stimulates peripheral chemoreceptors → hyperventilation)
3. Increased [hemoglobin] (hypoxemia stimulates EPO production)
4. Increased [2,3 DPG], HGB-O2 curve shifts right → facilitates O2 offloading
5. Right ventricle hypertrophy (due to increase in pulmonary vasoconstriction)
166
Which respiratory parasite can mimic asthma?
Aleurostrongylus
167
What is normal tidal volume?
10-15 ml/kg
168
Positive end-expiratory pressure (PEEP) will increase which lung volume?
Functional residual capacity
169
What is the major side effect of positive end expiratory pressure (PEEP)?
Increased thoracic pressure → decreased venous return
170
What is indicated by a PaO2 <65
1. Right to left shunt
| 2. SEVERE pulmonary disease → need for positive pressure ventilation
171
The A-a gradient should always be (number)
<10
| *Otherwise there is a V/Q mismatch
172
What does an increased A-a gradient indicate?
1. Shunt
2. V/Q Mismatch
3. Diffusion impairment
173
A low PaO2, high PCO2, and normal A-a gradient would indicate what?
Hypoventilation with normal lungs
174
The (PO2/PCO2) is the most important regulator of ventilation and most of the control is via the (peripheral/central) chemoreceptors
1. PCO2
| 2. Central
175
The (central/peripheral) chemoreceptors control most of the breathing and the (central/peripheral) chemoreceptors respond the fastest
1. Central
| 2. Peripheral
176
Which chemoreceptors can respond to hypoxia?
Peripheral
177
What are the best drugs to achieve effective concentrations in bronchial secretions?
1. Macrolides
2. Tetracyclines
3. Chloramphenicol
4. Fluoroquinolones
178
Abnormalities in which location will cause stertor?
Nose/nasopharynx
*Reverse sneezing is specific for the nasopharynx
179
Abnormalities in which location will cause stridor?
Larynx/trachea
180
Where do polyps arise in cats? dogs?
1. Eustachian tube or middle ear
| 2. Caudal nasal turbinates (consequence of chronic rhinitis)
181
Under diseased conditions, which portion of the airways give the highest resistance?
Smallest airways - due to smooth muscle contraction, congestion from edema or mucus
182
How does acetylcysteine break up mucus?
Breaks down disulfide bonds in mucus glycoproteins
183
Which breed is predisposed to bronchiectasis?
Cocker spaniels
184
Neutrophilic (+/- eosinophilic) infiltration of bronchial mucosa will result in production of what?
* Can occur in chronic bronchitis
1. Proteases
2. Elastases
3. Oxidizing products
185
What is a physical exam hallmark of chronic bronchitis?
Expiratory wheeze
186
What must be in the history for a cat to be diagnosed with chronic bronchitis?
DAILY cough
187
What is the primary mediator of feline mast cells?
Serotonin
*Important in feline asthma
188
Which bacteria that may be diagnosed on a BAL is not present in healthy cats?
Mycoplasma
189
How does mycoplasma increase bronchoconstriction/edema
Mycoplasma degrades endopeptidases → allows substance P to increase
190
Which lung lobe is most commonly torsed?
Right middle
191
What is Bernoulli's equation for use in calculating tricuspid regurgitation?
4xV^2 where V is the regurgitant jet
192
Which conditions will not respond to 100% oxygen supplementation?
1. Cyanide toxicity
2. Shunt
3. V/Q to infinity (ventilation but no perfusion)
193
How does the lung adapt to accommodate more blood during exercise?
1. Increases pulmonary blood flow (blood vessel dissension)
| 2. Decreases physiologic dead space (blood vessel recruitment)
194
How is bradykinin metabolized in the lung?
Degraded by ACE - 80%
195
How is serotonin metabolized in the lung?
There is uptake and storage - almost completely removed
196
How much norepinephrine is metabolized in the lung?
30% is removed
197
What happens to prostaglandins in the lung?
Prostaglandins E1, E2, F2α, and leukotrienes are inactivated
198
What is the mechanism behind cyanide toxicity?
Inhibits cytochrome C oxidase → prevents mitochondrial aerobic respiration (blocks the ETC)
199
What is the effect of cyanide toxicity on venous blood?
The venous O2 will increase (cherry red blood) due to the non-use of iron
200
How is cyanide toxicity treated?
1. Hydroxycobalamine
| 2. Nitrates/Thiocyanate
201
What substances are involved in pulmonary hypertension?
1. Decreased NO
2. Decreased prostacyclin
3. Increased endothelin-1
4. Increased thromboxane A2
5. Increased serotonin
202
What changes to epithelia are seen in bronchiectasis?
Squamous metaplasia and loss of pseudo stratified columnar epithelium
