Exam 2 Flashcards
How much blood enters the lungs from the right ventricle? A. 25% B. 66% C. 100% D. 0%
C. 100%
How big is a pulmonary?
A. Diameter of 1 RBC (10ums)
B. Diameter of human hair (17- 180um)
A. Diameter of 1 RBC (10ums)
Look at the slides 5-13/1
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What are the 5 predisposing factors for decreasing functional residual capacity?
– Positional changes. – Fasting. – Rumen or gastrointestinal distention. – Species. – Pregnancy.
What the mechanisms that can decrease functional residual capacity? (3)
– Atelectasis (lung collapse).
– Increased thoracic or abdominal blood volume
– Loss of diaphragm tone at end exhalation.
Look at slide 15/1
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KNOW THESE 4
What are the four types of hypoxia?
(WILL BE ON EXAM, KNOW/MEMORIZE THEM!!!!!!!!!!)
– Hypoxic hypoxia.
– Anemic hypoxia.
– Circulatory hypoxia.
– Histotoxic hypoxia
What is the definition of hypoxia?
Abnormally low partial pressure of O2 in tissues. From low oxygen delivery (D02)= CO x CaCO.
What is the definition of hypoxemia?
Abnormally low partial pressure of 02 in arterial blood (Pa02< 60mmHg)
What are the five causes of hypoxemia?(All are assoc. w/ hypoxic hypoxia)
– Hypoventilation – low fractional inspired oxygen concentration – ventilation perfusion mismatch – anatomical shunt – diffusion impairment
What can cause hypoventilation? (4)
*inverse relationship between Va and PaCO2
– anesthetics which depresses Central Drive – damage to chest wall – paralysis of respiratory muscles – high resistance to breathing (slide 17/1)
What is apparatus dead space? What is the issue this?
Apparatus dead space is the space that is taken by the breathing apparatus and doesn’t reach the animal. The issue is that you need to calculate for apparatus densities when figuring out the tidal volume for an animal so it gets full ventilation.
How do you minimize the apparatus dead space?
Can cut the tube
What is functional residual capacity?
Volume of gas remaining in lungs after normal expiration.
Do all patients that hypoventilate become hypoxic?
No
What is hypoventilation?
When you slow/stop breathing.
With a perfusion mismatch in zone one, what would you expect to see? (3)
*collapse
- Alveolar dead space
ventilation
- Lung is ventilated but not perfused
- Normally small component in awake healthy animals
With a perfusion mismatch in zone two and three, what would you expect to see?
*2:waterfall 3:Distention
- Vertical perfusion
gradient
What would you not expect to see with a low V/Q or inadequate ventilation?
A. Dead space ventilation with extremely low V/Q (shunt)
B. Pulmonary edema
C. Pneumonia
D. Atelectasis
E. Expect to see all of the above
E. Expect to see all of the above
What would you not expect to see with a high V/Q or inadequate ventilation? A. Poor pulmonary perfusion B. Pulmonary thromboembolism C. Expect to see all of the above. D. Wouldn't see any of the above. 
C. Expect to see all of the above.
What does V/Q inequality impair the lung from doing?
It impairs uptake or elimination of all gases by the lung.
Why can your CO2 be easier corrected by increasing ventilation versus your PO2?
CO2 is 20 times more soluble than O2
What is an anatomical shunt, and how does it play a role in hypoxia?
It is an abnormal vascular connection between the small pulmonary artery and vein. This causes a direct addition of venous blood to atrial blood across a defect between the right and left side.
These animals respond poorly to added inspired O2.
Hypoxemia due to an anatomical shunt is more severe when moving from which side to which side?
When moving from right to left.
*It is more common to see a left to right shunt
Fick’s Law of diffusion 31/1.
.
What can cause diffusion impairment that will lead to hypoxia?(3)
Pulmonary fibrosis, decrease in RBCs transit time through capillary (intense exercise), thickening of blood–gas interface (smoke inhalation, oxygen toxicity).
What is an example of low partial pressure of inspired oxygen? (Think going to Colorado to play a sport)
Altitude sickness (33/1)
What are the two causes of low partial pressure of inspired oxygen?
How does the body try to compensate?(34/1)
Causes:
- High altitude
- Oxygen supply to breathing circuit of anesthesia machine is interrupted
Compensations
- Change in p50 of oxygen dissociation curve
- Shift to the left
- Increase affinity of O2 to Hb
- Hyperventilation (Decreased H+)
- Low 2,3 DPG
P(A-a)O2 mmHg >30mmHg=?
P(A-a)O2 mmHg<20mmHg=?
Look at slide 18/1 notetaker notes.
> 30=Ventilation: perfusion inequality
<20=hypoventilation
Look at slide 36/1Notetaker notes
.
Which of the following is false about brachycephalic syndrome?
A. They have high resistance to breathing.
B. Respiratory muscle fatigue due to hyperventilation (does not maintain a normal PaO2)
C. Hypoxia and Hypercapnia with decompensation may happen
D. Get respiratory arrest
E. All of the above are correct.
B. Respiratory muscle fatigue due to hyperventilation (does not maintain a normal PaO2)
*it does maintain normal PaO2
What is the best way to prevent an animal with brachycephalic syndrome from needing CPR?
Prevent excitement (this is done by minimal restraint and possible sedatives)
What is the biggest issue involving equine postoperative obstructions?
Resistance to breathing due to being obligate nasal breathers.
What is laryngeal paralysis?
Denervation of recurrent laryngeal nerve
What are the causes of laryngeal paralysis?(7)(not a big deal)
Idiopathic, trauma, neuromuscular disease, neoplasia, hypothyroidism, neuro/myopathy, congenital.
How does laryngeal paralysis cause respiratory disease? (3) (these are important)
- increase upper airway resistance
- Increased inspiratory effort
- Dyspnea, syncope, hypoxia
What are you more likely to see in the upper respiratory issue, increased inspiratory prolongation/effort or expiratory prolongation/effort?
increased inspiratory prolongation/effort
How does the radius of the airway affect the work of breathing? (IMPORTANT WILL BE ON EXAM)
Decreasing radius will increase airway resistance requiring a more negative intraplueral pressure to be generated. This will increase the work of breathing.
If you have a high Reynolds number what is the breathing considered to be?
More turbulent. This also increases the work of breathing
What is heliox?
Mixture of oxygen and helium. Creates lower Reynolds number and thus turbulent flow.
What type of airflow (Turbulent or laminar) will a tracheal collapse cause?
Will this increase or decrease work of breathing? (48-52/1)
Turbulent
increase work of breathing
Define atelectasis.
In what type of patients is this an important cause of hypoxemia?
Airless or partly airless state of long leading to alveolar collapse.
Critically ill patients
What is the primary cause for lung collapse (atelectasis)?
Surface tension
What are the four forces that oppose surface tension?
Transpulmonary pressure, tethering affect of surrounding structures, surfactant, gaseous nitrogen skeleton
Look at slides 56-58/1
What can lead to atelectasis? (7)(think about lung collapse.)
Compression, airway obstruction, alveolar fluid accumulation, alveolar trauma, compromise of palm. perfusion, & absorption atelectasis.
What are the causes of atelectasis? (4) (59-62/1)
– inadequate expansion
– anesthesia
– anatomic predisposition
– extramural airway compression
What animal is it common to see inadequate expansion?
Large animals
What are the three examples of extramural airway compression?
Masses, pleural space disease, diaphragmatic hernia
What is pleural space disease?
It is a potential space formed by a parietal and visceral pleura.
What are the four things associated with pleural space diseases?
Pleural effusion, pneumothorax, diaphragmatic hernia, neoplasia
What is pulmonary edema?
Accumulation of extra vascular fluid within the pulmonary parenchyma or alveoli.
What are two things that can cause pulmonary edema?(67/1)
High-pressure edema and increased permeability edema.
What is the definition of pruritus/itch?(slide 4/2)
Unpleasant sensation stimulating the desire to itch.
True or false: axons that mediate the sensation of pain or itch are myelinated axons (C fibers).
False. The axons are unmyelinated.
Where are the cell bodies for itch located? (Pick specific ganglia) (5/2)
Cell bodies for itch are located in the dorsal root ganglia of spinal nerves & the trigeminal (Gasserian) ganglion of CN V.
Which of the below is responsible for receiving incoming action potentials and transmitting them to the brain?
A. Trigeminal ganglia on
B. Spinothalamic tract neurons in the dorsal horn
C. Dorsal root ganglia
D. Primary somatosensory cortex
B. Spinothalamic tract neurons in the dorsal horn
Which of the following is false referring to itch neurons.
A. they intersect or intercommunication with other morons especially those that mediate pain.
B. Pain often inhibits itch.
C. Opioid pain-relievers can cause pruritus.
D. Noxious temperature changes, both cold and hot, modulate itch perception. (bathing in hot water alleviates poison ivy itch)
E. All of the above are true
E. All of the above are true
Look at slide 8/2
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What are the four things pruritus results from?(9/2)(all are diseases)
Skin disease, systemic disease, neuropathic disease, psychogenic disease.
What are typical things that your owners will see with pruritus? (6)
Biting, licking, chewing, scratching, gnawing, rubbing.
Look at slide 11/2
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What are the trigger factors for pruritus?(9)
Which is the most common?
Allergens, bacteria, yeast, food, irritants, psyche, temperature, humidity, hormones.
Allergens
Define threshold (involving itch).(KNOW slide 13/2)
Patients can tolerate a certain load of sensations or pruritic stimuli without becoming itchy.
True or false: the threshold is the same for everyone.
False. Threshold varies among individuals.
What are the 3 general causes of pruritus in dogs?(KNOW)
Allergy, ectoparasites, infections.
What are the four allergy related causes of pruritus in a dog?
Flea allergy, atopic dermatitis, cutaneous adverse food reaction, insect bite hypersensitivity/contact dermatitis
What are the five ectoparasite related causes of pruritus in a dog?
sarcoptes, demodex, cheyletiella, lice, chiggers
What are the three infectious causes of pruritus in a dog?(slide 18/2)
Pyoderma, yeast, dermatophytes.
What are the six questions you would ask to characterize pruritus?
- What body sites?
- Any seasonality?
- How intense?
- Which came first: the itch or the skin lesion?
- Age of onset?
- Any helpful treatments?
Name cause of pruritis/itch at sites. (specific) 1.Caudal dorsum, 2. Elbows & ears, 3. feet licking/chewing.
Look at slide 21-23/2
CD=flea allergy
EE=Sarcoptes
FL/C=food allergy or atopy
What are the three diseases that are the most severe when it comes to pruritus?(Slide 22/2)
Scabies, flea allergy, food allergy
How is feline pruritus different from canine pruritus?(4)
– Owner might not recognize the problem.
– Body localization is not as distinctive.
– skin lesions are different
– Rarely: excoriation, lichenification, hyperpigmentation