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From Flashcardlet > Respiratory > Flashcards

Respiratory Flashcards

1
Q

Define hypoxia

A

Decrease in level of oxygen supplied to tissues

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2
Q

Define hypoxemia

A

Inadequate oxygenation of arterial blood and is defined as PaO2<80 mm Hg (at sea level)

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3
Q

DO2 =

A

CO x CaO2

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4
Q

List 5 causes of hypoxemia

A 
Hypoventilation
VQ mismatch
Diffusion impairment
Decreased FiO2
Intrapulmonary shunt
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5
Q

Which of the 5 causes of hypoxemia do not respond to oxygen supplementation?

A

Intrapulmonary shunt

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6
Q

When is supplemental oxygen indicated?

A

SpO2< 93%

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7
Q

Arterial oxygen content formula

A

[1.34 (ml O2/g) x SaO2 (%) x Hb (g/dL)] + [0.003 (ml O2/dl/mmHg) x PaO2 (mm Hg)]

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8
Q

Risks of using non-humidified oxygen:

A
  1. Drying and dehydration of nasal mucosa
  2. Respiratory epithelial degeneration
  3. Impaired mucociliary clearance
  4. Increased risk of infection
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9
Q

What is hyperbaric oxygen

A

100% oxygen under supraatmospheric pressures (>760 mm Hg) to increase the percent dissolved oxygen in bloodstream by 10-20%

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10
Q

Phases of oxygen toxicity

A
  1. Initiation: 24-72h of exposure to 100% O2; ROS damage
  2. Inflammatory phase: pulmonary epithelial lining destroyed and inflammatory cells recruited, massive release of inflammatory mediators results in increased tissue permeability and pulmonary edema
  3. Destruction: severe local destruction, many die
  4. Proliferation: type 2 pneumocytes and monocytes recruited
  5. Fibrosis: collagen deposition and interstitial fibrosis
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11
Q

Correlation b/t PaO2 and SaO2

A 
PaO2 500 = 100% SaO2
PaO2 125 = 99% SaO2
PaO2 100 = 98% SaO2
PaO2 80 (hypoxemia) = <90%

P50 PaO2 29, SaO2 50

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12
Q

Primary physiologic cause of hypoxemia.

A

Low FiO2
Global hypoventilation
Venous admixture

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13
Q

Causes of venous admixture

A

Low V/Q region
Atelectasis (no V/Q)
Diffusion defects
Right to left shunts (PDA, VSD, intrapulmonary AV shunt)

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14
Q

Thickness of an alveolar wall

A

0.3 um

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15
Q

What is the smallest airway without aveoli?

A

terminal bronchioles

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16
Q

Conducting ariways end with…

A

terminal bronchioles

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17
Q

What is anatomic dead space?

A

Airway w/o alveoli - ends at terminal bronchioles

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18
Q

Define acinus

A

portion of lung distal to terminal bronchiole

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19
Q

External intercostal muscles aid in..

A

Inhalation

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20
Q

Internal intercostal muscles aid in…

A

Forced exhalation

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21
Q

Where does the velocity of gas decrease the most in the?

A

terminal bronchioles (so inhaled particles end up here most)

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22
Q

Weibel diagram

A

Conducting zone = trachea –> bronchi –> bronchioles –> terminal bronchioles

Transitional and respiratory zone –> respiratory bronchioles –> alevolar ducts –> alveolar sac

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23
Q

Respiratory capillary diameter

A

7-10 um

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24
Q

How long does an RBC spend in the capillary network?

A

0.75 s

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25
Q

Bronchial circulation supplies.

A

Conducting zone (trachea to terminal bronchioles)

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26
Q

Surface area of the lungs

A

50-100 meters squared

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27
Q

aveoli in lung

A

500 million

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28
Q

Alveoli diameter

A

0.3 mm

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29
Q

Function of surfactant

A

Decrease surface tension in alveoli

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30
Q

When oxygen moves from the thin side of the blood-gas barrier from the alveolar gas to hemoglobin of the RBC, it traverses the following layers in order:

A

Surfactant, epithelial cell, interstitium, endothelial cell, plasma, red cell membrane

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31
Q

What is the PO2 of inspired gas at Mt. Everest (barometric pressure of 247 mm Hg)?

A

247-47 (water vapor) x 0.21 = 42 mm Hg

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32
Q

What is the predominant mode of gas flow in the alveolar ducts?

A

Difffusion

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33
Q

Define tidal volume

A

volume inspired normally

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34
Q

Devine vital capacity

A

Max inspiration and max expiration = inspiratory reserve volume + tidal volume + expiratory reserve volume

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35
Q

Residual volume

A

gas that remained in lung after maximal expiration

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36
Q

Functional residual capacity

A

volume of gas in lung after a normal expiration = expiratory reserve volume + residual volume

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37
Q

Inspiratory capacity

A

Tidal volume + inspiratory reserve volume

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38
Q

What does Boyle’s law state?

A

Pressure x volume is constant (at constant temperature)

PV = K

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39
Q

What is alveolar ventilation?

A

Volume of fresh gas entering the respiratory zone each minute; (tidal volume - dead space) x resp freq

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40
Q

How can you increase alveolar ventilation?

A

increased tidal volume or respiratory frequency

Increasing tidal volume more effective b/c reduces proportion of each breath occupied by anatomic dead space

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41
Q

What is the alveolar ventilation equation?

A

VA = (VCO2/PCO2) x K

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42
Q

What is anatomic dead space?

A

Volume of the conducting airways

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43
Q

What is the Bohr equation?

A

VD/VT = (PACO2-PECO2)/PACO2

VD = dead space
VT = tidal volume
A = alveolar
E = mixed expired

Bohr eqn: AEA (my initials:)

All of the expired CO2 comes from the alveolar gas and none from the dead space. MEASURES PHYSIOLOGIC DEAD SPACE

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44
Q

What is the normal ratio of dead space:tidal volume during resting breathing?

A

0.2-0.35

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45
Q

What is physiologic dead space?

A

Volume of gas that does not eliminate CO2

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46
Q

T/F. Anatomic dead space increases with many lung diseases

A

F - physiologic dead space increases

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47
Q

T/F. Upper regions of the lung ventilate better than lower regions.

A

F - Lower regions ventilate better than upper zones

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48
Q

What lung volumes cannot be measured with a simple spirometer?

A

total lung capacity, functional residual capacity, residual volume

They can be measured with helium dilution or body plethysomograph

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49
Q

T/F. The concentration of CO2 (and therefore its partial pressure) in alveolar gas and arterial blood is inversely related to the alveolar ventilation.

A

T

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50
Q

What does Fick’s law state regarding diffuson?

A

The rate of transfer of a gas through a sheet of tissue is proportional to the tissue area and the difference in gas partial pressure between the two sides, and inversely proportional to the tissue thickness

Diffusion rate proportional to partial pressure difference

Diffusion rate proportional to solubility of gas in tissue and inversely propotional to its molecular weight

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51
Q

CO2 diffuses ____ times more rapidly than O2 because it ha a higher _____

A

20 x

solubility

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52
Q

Transfer of carbon monoxide is….

A

diffusion limited b/t the amt of CO that gets into blood limited by diffusive properties and not amt of blood available

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53
Q

What gas is perfusion limited?

A

nitrous oxide (doesn’t bind with Hbg so partial pressure rises rapidly in blood, so blood flow depends on uptake)

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54
Q

T/F. Under resting conditions, the capillary PO2 virtually reaches that of alveolar gas when red cell is 1/3rd the way along the capillary.

A

T

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55
Q

Diffusion process challenged by:

A

exercise, alveolar hypoxia, thickening of the blood-gas barrier

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56
Q

Normal diffusing capacity

A

25 ml/min/mmHg

carbon monoxide used to determine

Formula = VCO2/PACO2

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57
Q

T/F. Oxygen transfer is normally diffusion limited.

A

F - Perfusion limited

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58
Q

Under what circumstances does oxygen transfer become diffusion limited?

A

Intense exercise, thickened blood-gas barrier, alveolar hypoxia

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59
Q

What is transmural pressure?

A

Pressure difference between the inside and outside of capillaries

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60
Q

What is normal pulmonary vascular resistance?

A

1.7 mm Hg/L/min

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61
Q

What are the two mechanisms for why an increase in pulmonary arterial venous or arterial pressure causes the pulmonary vascular resistance to fall?

A

Recruitment (opening of previously closed) and distension (increase caliber of vessels)

Recruitment more with increase in arterial pressure
Distention more with increase in venous pressure

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62
Q

What is hypoxic pulmonary vasoconstriction?

A

Contraction of smooth muscle in the walls of the small arterioles in the hypoxic region. PAO2 of pulmonary gas determines this reaction. When PAO2 < 70 mm Hg, marked vasoconstriction occurs.

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63
Q

What is the primary constituent of pulmonary surfactant?

A

dipamlitoyl phosphatidylcholine

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64
Q

Ratio of total systemic vascular resistance to pulmonary vascular resistance

A

10:1

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65
Q

What two wave wavelengths do pulse oximeters use?

A

660 and 940 mm

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66
Q

What are the 4 causes of venous admixture?

A

low VQ regions, small airway and alveolar collapse (atelectasis), diffusion defects, anatomic right to left shunts

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67
Q

T/F Cats have a right shift oxygemoglobin dissociation curve compared to dogs

A

T

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68
Q

What are examples of diffusion defects for venous admixture?

A

Oxygen toxicity, smoke inhalation, ARDS

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69
Q

T/F. Oxygen concentration is lower at higher altitudes

A

F - Still 21%, barometric pressure is lower so PatmO2 is lower

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70
Q

What gas is highest in the alveoli?

A

nitrogen (560 mm Hg)

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71
Q

T/F. Hypoventilation is a cause of hypoxemia in patients breathing room air but not in patients breathing enriched oxygen mixtures

A

T - With 100% oxygen, nitrogen is decreases to nearly 0 and oxygen increases to 665, alveolar CO2 could theoretically rise to 550 mm Hg before the alveolar oxygen decreased to a level that would lead to hypoxemia (PaO2 <80)

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72
Q

What is the difference between a physiologic shunt and a true or anatomic shunt?

A

physiologic: blood flowing past nonfxnal alveoli
true: blood completely bypasses alveoli (be they fxnal or not)

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73
Q

What cell proliferation is responsible for diffusion defect?

A

cuboidal, type 2 pneumocytes (normal is flat type 1)

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74
Q

What is the normal A-a gradient?

A

20 mm Hg = venous admixture

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75
Q

What is minute ventilation?

A

TV x RR

alveolar and dead space ventilation

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76
Q

What are causes of hypercapnia?

A

hypoventilation, increase in dead space ventilation, increased CO2 production, increased inspired CO2

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77
Q

Fowler’s method measures what?

A

Anatomic dead space

Measures concentration of a tracer gas (nitrogen) over time

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78
Q

Bohr’s method measures what?

A

Physiologic dead space

Volume of lung that does not eliminate CO2

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79
Q

What is the conclusion from the alveolar ventilation equation (VA = (VCO2/PaCO2) x K)

A

The only physiologic reason for increased PaCO2 is level of alveolar ventilation that is inadequate for the amount of CO2 produced by tissues

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80
Q

Normal dog PaCO2

A

30-42 mm Hg

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81
Q

Normal cat PaCO2

A

25-36 mm Hg

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82
Q

Venous CO2 is usually ___ higher than arterial CO2

A

3-6 mm Hg

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83
Q

What are the 3 neurons involved in the respiratory control center in medulla and pons?

A
  1. medullary respiratory center
  2. apneustic center
  3. pneumotaxic center
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84
Q

The medullary respiratory center is split into ….

A

Dorsal and ventral respiratory group

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85
Q

What is special about the dorsal respiratory group?

A

Located in region of nucleus tractus solitarius, where visceral afferents from cranial nerves IX and X terminate

responsible primarily for INSPIRATION (intrinsic periodic firing)

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86
Q

What are the 4 nuclei in the ventral respiratory group of the medullary resp center?

A
  1. Nucleus retrroambiguus
  2. Nucleus para-ambiguus
  3. Nucleus retrofacialis
  4. pre-Botzinger complex
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87
Q

What is the job of the ventral resp group of medullary resp center?

A

Controls voluntary forced exhalation and acts to increase the force of inspiration

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88
Q

What does the apneustic center do?

A

coordinates the speed of inhalation and exhalation; can be over ridden by pneumotaxic center

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89
Q

Where is the apneustic center?

A

lower (ventral) pons

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90
Q

Where is the pneumotaxic center and what does it do?

A

upper (dorsal) pons

Sends inhibitory impulses to the inspiratory center, terminating inspiration, and regulates inspiratory volume and RR

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91
Q

The descending automatic pathways (in anterolateral white matter of cord) are where…

A

paramedian reticular formation of the medullary and pontine tegmentum and laterally in the high cervical cord in close proximity with the spinothalamic tract

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92
Q

The descending voluntary pathways are where…

A

associated with the corticospinal tracts in brainstem and upper cervical cord

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93
Q

Phrenic motor neurons are where?

A

C3-C5

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94
Q

Intercostal motor neurons were where?

A

T2-12

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95
Q

Where are central chemoreceptors found?

A

medulla

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96
Q

Where are peripheral chemoreceptors found?

A

carotid and aortic bodies

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97
Q

Central chemoreceptors responsible for ___% of resp response to CO2

A

85%

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98
Q

What happens to CO2 that diffuses into brain?

A

Hydrated to carbonic acid –> dissociates to H+ and HCO3-; so the H+ is what actually stimulates respiration

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99
Q

Peripheral chemoreceptors respond to these 4 things to increase ventilation

A

Decreased pH, decreased PaO2, increased PaCO2, hypoperfusion

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100
Q

Peripheral chemoreceptors are exclusively responsible for the increased ventilation secondary to _____

A

hypoxemia

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101
Q

What is the Hering-Breuer inflation reflex?

A

pulmonary stretch receptors in SM respond to excessive stretch with large inspiration by sending action potentials thru large myelinated fibers of the vagus nerve to inspiratory area of medualla and apneustic center in pons; inhibits inspiratory discharge

main effect = slowing respiratory frequency by increasing expiratory time

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102
Q

Where are “irritant receptors” and what do they do?

A

Between airway epithelial cells, stimulated by noxious gases, cold, and inhaled dust; send AP via vagus causing BRONCHOCONSTRICTION AND INCREASED RR

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103
Q

What are “J” receptors and what do they do?

A

juxtacapillary receptors in alveolar walls close to capillaries

respond rapidly to chemicals in pulm circulation, distension of capillary walls, and accumulation of interstitial fluid to cause rapid, shallow breathing

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104
Q

How are arterial baroreceptors involved in ventilation?

A

Low blood pressure - hyperventilation

Large increase BP - hypoventilation

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105
Q

Strength of muscle contraction to inspire must overcome two main sources of impedance:

A
  1. elastic recoil of lungs and chest wall

2. resistance to gas flow (upper airways)

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106
Q

Carbon dioxide narcosis

A

PaCO2 > 90mmHg

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107
Q

What accounts for the normal v-a CO2 difference?

A

10% dissolved CO2 and 90% bound CO2 in RBC as bicarbonate from tissues back to lungs

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108
Q

What 3 things affect venous CO2?

A

PaCO2, de novo tissue CO2 production, tissue blood flow

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109
Q

What does Henry’s law say?

A

The amount of dissolved gas if proportional to the partial pressure

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110
Q

What is oxygen capacity?

A

Maximum number of O2 that can combine with Hb

Normal is 20.8 ml O2/dL blood

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111
Q

What is oxygen saturation?

A

Percentage of available binding sites that have oxygen attached.

O2 combined with Hb / O2 capacity x 100

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112
Q

What are the conformational changes to hemoglobin in respect to oxygenation of Hb?

A

R (relaxed) state with oxygenated

T (tense) state when deoxygenated

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113
Q

What shifts the oxygen dissociation curve to the right?

A

Increased temperature, 2,3-DPG, PCO2, hydrogen ions

Remember exercising muscle is hot, acidotic, hypercarbic and needs more oxygen in tissues

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114
Q

T/F. A right shift on the oxygen dissociation curve means the affinity of oxygen to hemoglobin is stronger.

A

F - means it is weaker so more O2 can be unloaded to tissues for the same given PO2

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115
Q

What is 2,3 DPG?

A

2,3-diphosphoglycerate = end product of red cell metabolism. This increased in chronic hypoxia and high altitudes. In stored RBC, 2,3-DPG reduced, so may not be that great at offloading oxygen.

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116
Q

A small addition of carbon monoxide to blood causes a left or right shift to O2 dissociation curve?

A

Left

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117
Q

Carbon monoxide affinity for Hb is ___ times greater than oxygen’s affinity for Hb

A

240

Means same amt of CO with bind with Hb when partial pressure of CO is 240 times lower than oxygen’s PP

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118
Q

What is the Bohr effect?

A

The effect of pCO2 shifting curve to right because of it’s action on H+ ions

119
Q

Where is carbonic anhydrase highest?

A

RBC

120
Q

What is the chloride shift?

A

In the RBC, CO2 + H2O –> carbonic acid –> HCO3 and H. The bicarb diffuses out, but H can’t b/c cell membrane impermeable to + cations; so ensure a happy RBC, chloride shifts in to make it a neutral ground again

Gibbs-Donnan equilibrium

121
Q

What is the Haldane effect?

A

Deoxygenated blood increases its ability to carry CO2…..why….because reduce Hb is less acidic and can take on a proton; so reduced Hb in periphery makes it easier to load CO2, and oxygenation in the lungs, makes it easier to unload CO2

122
Q

How is CO2 removed from tissues?

A

10% dissolved, 60% HCO3, 30% carbaminoHb

123
Q

Normally PETCO2 underestimates PaCO2 by __ mm Hg

A

2-6

124
Q

What are the 3 mechanisms for oxygen induced hypercapnia in patients with chronic hypoventilation?

A
  1. Depression of formerly hypoxic-driven peripheral chemoreceptors causing worsening of hypovenilation
  2. Relief of hypoxic pulmonary vasoconstriction in poorly ventilated lung regions that further reduces the ability of these units to eliminate CO2 as local perfusion increases w/o increase in ventilation
  3. Better saturation of Hgb so that previously buffered protons on deoxyhemoglobin are released with subsequent generation of CO2 from stores (Haldane effect)
125
Q

List respiratory stimulants

A

Doxopram, theophylline/aminophylline, caffeine, progesterone

126
Q

What is orthopnea?

A

Extension of the head and neck while breathing

127
Q

Where is 80% of the resistance to airflow during inspiration in the dog?

A

nose

128
Q

Nasal turbinates protruding into the nasopharynx has been documented in __% of dogs with BAS, with the ___% being in Pugs.

A

20%, 80%

129
Q

___ % of dogs with BAS has some degree of bronchoscopically detectable collapse or stenosis and that worsened degree of bronchial collapse was associated with ______ collapse.

A

87%, laryngeal

130
Q

Esophagitis, gastritis, reflux, hiatal hernia, and pyloric stenosis reported in ____ % of dogs with BAS.

A

80% - worsened their resp signs

131
Q

T/F. cTnI increased and CRP and haptoglobin normal in BAS dogs

A

T

132
Q

What is the most important part of BAS surgery?

A

A good nose job!!! Imparts the most airway resistance.

133
Q

T/F Tracheal hypoplasia and bronchial collapse means outcome worse with BAS surgical treatment.

A

F

134
Q

What is the surgical procedure to fix a collapsed larynx?

A

Cricoarytenoid lateralization combined with thyroarytenoid caudolateralization (arytenoid laryngoplasty)

135
Q

Which cell makes surfactant?

A

type 2 pneumocyte

136
Q

What is the main substance of surfactant?

A

Dipalmitoyl phosphatidylcholine

137
Q

___% of cats with nasopharyngeal disease have polyps.

A

28%

138
Q

Traction avulsion of NP polyps in cats ass’d with ___% recurrence.

A

40-50%, esp if from auditory canal

139
Q

If NP polyp from auditory tube or middle ear dz present, recommendation should be…

A

VBO

140
Q

Horner’s syndrome VBO vs. traction avulsion

A

57% vs. 43%

141
Q

Larynx accounts for ___% of resistance to airflow during nasal breathing

A

6

142
Q

Causes of lar par

A

congenital denvervation, traumatic, iatrogenic, idiopathic, neoplastic, diffuse NM dz (MG and hypoT4)

143
Q

Breeds associated with congenital lar par

A

Bouvier des Flandres, Rotties, Dalmations, Siberian Huskies (and mixes), Bull Terriers, Pyrenean Mountain Dogs, Leonbergers

144
Q

T/F. Liquid phase esophagram better predicts post op aspiration than neuro status with lar par.

A

T

145
Q

What are surgical techniques to fix lar par

A
  1. widen dorsal glottis (unilateral or bilateral arytenoid lateralization)
  2. widen ventral glottis (focal fold resection, partial laryngectomy, modified castellated laryngofissure)
  3. widen both (castellated laryngofissue and bilateral arytenoid lateralization)
146
Q

Incidence of aspiration after lar par sx

A

8-33%

147
Q

T/F. Cats with lar par are older or younger than dogs.

A

Older (8-16y)

148
Q

Radiographs misdiagnosed the location of tracheal collapse in ___% of dogs, and failed to diagnose tracheal collapse in ___% of dogs when compared to fluorscopy.

A

44%, 8%

149
Q

___% of dogs with cervical tracheal collapse also had concurrent bronchial collapse.

A

83%

150
Q

Lar par diagnosed in ___% of dogs with tracheal collapse.

A

30% (vet surg, 1982)

151
Q

Pathogens that can be cultured from normal dog lungs

A

Pasteurella, Staph, Strept, Klebsiella

152
Q

Most common isolated bacteria from dogs with tracheal collapse.

A

Pseudomonas, Pasteurella, E.coli, Staph

153
Q

T/F Bronchoscopic removal of trach foreign bodies has better success in cats vs dogs

A

F. Dogs 86%, cats 40%

154
Q

Most common nasal tumors in dogs vs. cats.

A

Dogs - carcinoma/sarcoma, cats- LSA

155
Q

Most common laryngeal tumor in dogs?

A

osteochondroma (usually young dogs < 2y)

156
Q

Most common laryngeal tumor in cats?

A

LSA

157
Q

Median age of laryngeal tumors?

A

9 y (exception, dogs osteochondroma < 2 y)

158
Q

Sleep study in Bulldogs showed what?

A

5 bulldogs had SpO2<90% during 32% of time in REM, no control had this. Mean REM sleep SpO2 Bulldogs (78+/-5%) and controls (95 +/-2%)

159
Q

What is a staphlectomy?

A

Resection of the soft palate

160
Q

Laryngeal collapse in BDs has been correlated with the severity of ____.

A

Bronchial collapse.

161
Q

__ % of BDs had GI abnormalites (endoscopic and biopsies)

A

97%

162
Q

What is the Precision Flow?

A

Device that provides high flow (40 L/min) of humidified, warmed oxygen to help support airway patency

163
Q

What was the conclusion of the NTT study in brachycephalics?

A

5 dogs w/o NTT oxygen developed resp distress, no dog with NTT oxygen developed resp distress; 4 dogs with NTT had to have it removed d/t vomiting, regurg, or coughing

164
Q

T/F BDs have lower PaO2 and higher PaCO2

A

T

165
Q

What kind of endotracheal tube has been assc’d with tearing of the dorsal tracheal membrane in cats?

A

low volume,high pressure cuffs

166
Q

How much of the trachea can be resected in dogs?

A

20% yound dog, 25-50% older dog

167
Q

What is the most appropriate way to re-anastomose tracheal rings from traumatic trachea tears in medium to large dogs?

A

Split cartilage technique - tracheal cartilage at the proximal and distal ends of the anastomosis is split circumferentially using an 11 blade, then prepalced sutures (8-12 of them) with 3/0 or 4/0 monofilament material around the opposite cartilage halves and thru the dorsal tracheal membrane on either side of the anastomosis; less risk of luminal stenosis than annular ligament and cartilage technique; doesn’t work in small patients

168
Q

What is the most appropriate sx technique to re-anastomose the trachea in smaller animals?

A

cartilage technique; resect annular ligament on each side and suture the two cartilages together with preplaced sutures

split cartilage technique doesn’t work b/c cartilages fragment due to size

169
Q

In cats with trach tears secondary to intubation, where was the most common site?

A

Thoracic inlet on the dorsolateral aspect of the trachea at the jxn of the tracheal rings and trachealis muscle

170
Q

Surgical approach for an intrathoracic tracheal tear?

A

Right lateral thoracotomy (3rd-4th intercostal space)

171
Q

Minimum volume of air in high volume, low pressure cuff to create an airtight seal in cats.

A

0-3 mm

172
Q

Cuff pressures (measured with pressure manometer attached to endotrach cuff) should be kept within ___ and ____ mm Hg to provide sufficient seal without compromising tracheal mucosal perfusion.

A

20-30 mm Hg

173
Q

Most common parasite to cause allergic response in canine lungs?

A

Toxocara canis

174
Q

T/F. Strongyloides stercoralis migrates through cat lungs only, not dogs.

A

F - both

175
Q

List 4 primary lung parasites

A 
Paragonimus kellicotti (both)
Aelurostrongylus abstrusus (cats only)
Capillaria aerophila (both)
Filaroides hirthi (dogs only)
176
Q

What is canine allergic bronchitis (eosinophilic bronchopneumopathy)

A

a. Eosinophilic infiltration of lung and bronchial mucosa
b. Younger (3.3 +/- 2y)
c. Siberian Huskies and Alaskan malamutes overrepresented
d. Prominent bronchointerstitial pattern on rads
i. 40% alveolar pattern d/t secondary pneumonia
ii. 26% bronchiectasis
e. Peripheral eosinophilia 60%
f. BAL cytology
i. >50% eos in 87% dogs
ii. 20-50% eos in 13% dogs

177
Q

What is PIE (pulm infiltrates with eos)

A

a. Type I hypersensitivity
b. Possible stimuli: pulmonary or migrating parasites, HWD, drugs, inhaled allergens
c. 65% d/t HWD
d. Pulmonary parenchymal dz – signs rapid, shallow breathing, cyanosis
e. Rads: diffuse interstitial, bronchial, or alveolar pattern +/- hilar lymphadenopathy
f. Cytology: predominance eos in airways

178
Q

What are the two classes of bronchodilators?

A 
Methylxanthines (aminophylline, theophylline)
B2 agonists (albuterol, terbutalline)
179
Q

What is the reflection coefficient (sigma)

A

relative permeability of the membrane to protein; 1 = 100% impermeable so the protein is 100% reflected

180
Q

What is the filtration coefficient (K)

A

measure of the overall flow from the vasculature of specific tissues and is dependent on capillary surface area and hydraulic conductivity

181
Q

What are the two types of pulmonary edema?

A

High-pressure edema

Increased permeability edema

182
Q

T/F. The filtration coefficient is reduced when increased permeability edema

A

F - reflection coefficient reduced, memebrane more permeable to protein

183
Q

Pulmonary edema fluid is largely cleared by…

A

Bronchial circulation

184
Q

____ % of cats with left sided CHF have no cardiac auscultable abnormalities

A

20

185
Q

What are risk factors for ALI/ARDS (Dorothoy Russell Havemeyer)

A 
inflammation
infection
sepsis
SIRS
severe trauma (long bone fx, head injury, pulm contusion)
multiple transfusions
smoke inhalation
submersion injury
aspiration of stomach contents
ingestion of drugs and toxins
186
Q

What are some causes of increased permeability edema?

A

ALI/ARDS
PTE
VALI
inhaled toxins (hydrocarbons)

187
Q

What are causes of mixed high-pressure and increased permeability edema?

A

neurogenic pulmonary edema (seizure, shock, TBI)

negative pressure pulmonary edema (airway obst)

188
Q

Particle smaller than __ microns bypass the upper resp tract defenses and are deposited in the alveoli.

A

3 um

189
Q

What antibiotics penetrate the lung tissue?

A

chloramphenicol, doxycycline, enrofloxacin, TMS, clindamycin

190
Q

What are the risks/benefits or using bronchodilators to treat pneumonia?

A

Risks: suppress cough, worsen VQ mismatch, spread exudates to other areas of lung

Benefits: increase airflow, improve mucokinetics, methylxanthings may increase speed of mucociliary transpor, inhibit degranulation of mast cells, and decrease microvascular permeability and lead; aminophylline is also a resp stimulant and increases strength of diaphragmatic contraction

191
Q

How does NAC fxn as a mucolytic?

A

Breaks disulfide bonds in thick airway mucus; inhaled can cause bronchoconstriction in pets

192
Q

Nebulizer particle size has to be < or = to…

A

3 microns

193
Q

___ % of cats have no signs of pneumonia

A

36%

194
Q

____% of dogs with pneumonia have concurrent predisposing disorder

A

36-57%

195
Q

___% of cats with pneumonia cough; compared with ___% of dogs

A

8%, 47%

196
Q

What should be done after a lung aspirate?

A

Place patient on aspirate side down for 30-60 min

197
Q

Common bacteria in pneumonia?

A

Pasteurella (22-28%), E.coli (17-46%), Staph (10-16%), Strept (14-21%), Bordetella (49%, mostly puppies), anaerobic (10-20%), mycoplasma (sole inf 8%, mixed 62%)

198
Q

What is the cause of an emerging a syndrome of acute, hemorrhagic, fatal pneumonia in dogs from shelters?

A

Strept equi subspp zooepidemicus (Lancefield Group C)

199
Q

List the criteria for ALI/ARDS accoring to the Dorothy Russell Havameyer criteria.

A
  1. Acute onset
  2. Risk factors
  3. Evidence of increased transcapillary leak w/o increased pulm cap pressure pressure
  4. Evidence inefficient gas exchange
  5. Diffuse pulmonary inflammation (optional)
200
Q

List the risk factors for Vet ALI and ARDS.

A 
Inflammation
Infection
Sepsis
SIRS
Trauma (long bone fx, pulmonary contusions, head trauma)
Multiple transfusions
Smoke inhalation
Near-drowning
Aspiration stomach contents
Drugs/toxins
201
Q

Kelmer, JAVMA, 2009. What were the findings from the study on nasal catheter ETCO2 compared with PaCO2 in critically ill dogs?

A

Mean diff 3.95 +/- 4.9 w/o supplemental oxygen

Mean diff 6.87 +/- 6.4 w/ supplemental oxygen

Mean diff w/ resp disease (9+/-5) much higher than w/o resp disease (3+/-3)

Good correlation (r=0.833)

Cath size, ventilatory status, and outcome no sig assc’d with diff b/t ET and Pa CO2

202
Q

Kogan, JAVMA, 2008. Which breed were more likely to have aspiration pneumonia?

A

Goldens, Cockers, English Springers, Pugs

203
Q

Rice, Chest, 2007. SF ratio of <200 (ARDS)

A

85, 85

204
Q

Rice, Chest, 2007. FS ratio of < 315 was ___ senstiive and __ specific for detecting PF < 300 (ALI)

A

91%, 56%

205
Q

Aspiration pneumonitis can be caused by inhalation of the following…

A

gastric contents, freshwater, saltwater, hydrocarbons

206
Q

Severity of injury after aspiration of gastric content depends on…

A

pH, volume, osmolality, presence of particulate matter

207
Q

What percent of aspiration pneumonia cases reported to be complications of anesthesia?

A

5-26%

208
Q

What is the most common risk factor for aspiration pneumonia?

A

GI disorders (60%), followed by neuro (18%), laryngeal dz (13%)

209
Q

Reported survival rate after aspiration pneumonia?

A

77-82%

210
Q

Effect of pH on severity of lung injury after aspiration?

A

2.4 minimal unless particulate matter present

211
Q

What is the biphasic pathogenesis of acid-induced lung injury?

A

Initial (peaks at 1-2 h): caustic effects of acid damage bronchial and alveolar epithelium and pulm cap endothelium, stimulates substance P immunoreactive neurons involved in control of bronchial SM tone and vascular permeability. Stimulation of subP neurons induces tachykinin, peuropeptidase release, causing neurogenic inflammation, bronchoconstriction, vasodilation, and increased vascular permeability. Histologically, epithelial and endothelial degeneration, type I cell necrosis, intraalveolar hemorrhage.

Second (4-6h): larger inc pulm cap permeability and protein extravasation, edema, VQ mismatch, reduced compliance, chemotactic mediates (IL-8, TNF-alpha, macrophage inflammatory protein 2) attracts neutrophils which increase ROS, proteinases, and complement proteins. Complement induced mast cell release can cause damage to contralateral lung.

212
Q

T/F - Particular matter (w/o acid) aspiration causes severe pulmonary edema.

A

F - inflammation, no edema

213
Q

Sensitivity of TTW to diagnose bacterial pneumonia.

A

45-70%

214
Q

Thoracic trauma reported in ___ % dogs and ___% cats that sustain limb fractures from road accidents.

A

34-57%, 17%

215
Q

What is the spalling effect in relation to pulmonary contusions?

A

A shearing or bursting phenomenon that occurs at gas-liquid interfaces and may disrupt the alveolus at the point of initial contact with shock wave.

216
Q

What is the inertial effect in relation to pulmonary contusions?

A

Occurs when low-density alveolar tissue is stripped from heavier hilar structures as they accelerate at different rates resulting in both mechanical tearing and laceration of the lungs

217
Q

What is the implosion effect relating to pulmonary contusions?

A

Rebound or overexpansion of gas bubbles after a pressure wave passes, which can lead to tearing of pulmonary parenchyma from excess distension

218
Q

What does Henry’s Law say?

A

The amount of gas which dissolves in a unit volume of a liquid at a given temperature is directly proportional to the partial pressure of the gas in the equilibrium phase

CO2:O2 = 24:1

Solubility coefficient

219
Q

Rate of oxygen diffusion dependent on…

A

FiO2, alveolar ventilation, pulmonary capillary blood flow, oxygenation of hemoglobin

220
Q

Factors that cause contraction and increase in RV pressure:

A

Noradrenaline, adrenaline

dopamine, PGF2alpha, TXA2, histamine (H1), serotonin, angiotensin II

221
Q

Factors that cause dilation and decrease RV pressure.

A

isoproterenol, aminophylline, ganglion blcokers, PGE1, PGI2, histamine (H2), acetylcholine, bradykinin

222
Q

What causes the normal physiological shunt?

A

Coronary blood enters LV via thebesian veins; some bronchial artery blood enters the pulmonary veins

223
Q

What can increase the A-a gradient?

A 
Pulmonary collapse/consolidation
Neoplasia
Infection
Alveolar destruction
Drugs
Hormones
Extrapulmonary shunting
venous admixture
alveolar PAO2
Cardiac output
Oxygen consumpation
Anemia
P50 dissociation curve
Alveolar ventilation
224
Q

What is the Bohr effect?

A

Increased CO2 produces a pH independent shift of curve to right with decreased affinity for oxygen

225
Q

T/F Normal adult hemoglobin has iron in the ferrous state Fe++

A

T

If oxidized to Fe+++ forms metHb

226
Q

How do you treat methemoglobinemia?

A

methylene blue

227
Q

What is the Haldane effect?

A

Deoxy Hb is more basic than oxy Hb and accepts H+ more readily

so…reducing the PO2 and Hb saturation increases the CO2 carrying capacity of the blood

228
Q

What causes reduced compliance of lungs with pleural space disease?

A

reduced FRC which forces lung to operate on a less compliant portion of the compliance curve

229
Q

Sigrist, JVECC, 2011. Pleural space disease was significnantly associated with what type of breathing pattern?

A

Costoabdominal breathing (exaggerated abd component) and asynchronous breathing (outward mvmt chest and inward mvmt abd during inspiration)

230
Q

Sigrist, JVECC, 2011. Asynchronous breathing was * assc’d with…in cats.

A

Pleural effusion and chest wall localization

231
Q

Sigrist, JVECC, 2011. Inspiratory dyspnea (prolonged insp, short exp) was associated with upper airway dz in bth dogs and cats.

A

F - only dogs

232
Q

In dogs, what muscles elevate the ribs during inspiration?

A

External intercostals and the internal intercartilagenous intercostal muscles

233
Q

Sigrist, JVECC, 2011. Animals (dogs and cats) with pleural space disease showed predominantly ______ breathing. SE and SP for animals with pleural space dz showing an asynchronous or inverse breathing type in combination with decreased lung sounds on auscultation was ___ and ____, respectively.

A

asynchronous, 99%, 40%

234
Q

What is the expected compensatory response in PaCO2 from metabolic acidosis?

A

Decrease in PaCO2 by 0.7 mm Hg per every 1 mEq/L decrease in plasma bicarb

235
Q

Hypoxemia becomes the primary stimulation for ventilation when the PaO2 drops below…

A

50 mm Hg

236
Q

Causes of hypoglycemia in animals (can cause diminished resp muscle fxn):

A 
Excess insulin (iatrogenic, insulinoma)
Severe liver dz (PSS, glycogen storage, failure)
Insulinlike hormone secreting tumors (hepatic carcinoma, HSA, leiomyoma)
Metabolic dz (Addisons, GH deficiency)
Neonatal and juvenile hypoglycemia
Toxicosis (xylitol, ethanol)
Sepsis
Pregnancy toxemia
Polycythemia
Hunting dog hypoglycemia
237
Q

How do you reverse nondepolarizing paralytic agents (atracurium, vecuronium, pancuronium)?

A

Wait - 30-45 minutes; or…give anticholinesterase (edrophoium, physostigmine, neostigmine) and an anticholinergic (atropine, glyco)

238
Q

What are the 3 types of ventilator breaths?

A

Spontaneous: patient determines RR and TV
Assisted: patient determines RR, machine sets TV
Controlled: machine sets RR and TV

239
Q

How is PEEP helpful?

A

recruiting previously collapsed alveoli, preventing further alveolar collapse, reducing ventilator induced lung injury

240
Q

List some differentials for patient-ventilator asynchrony.

A

hypoxemia, hypercapnia, pneumothorax, hyperthermia inappropriate ventilator settings, full urinary bladder or colon, inadequate depth of anesthesia

241
Q

What are some indications of pneumothorax in the PPV patient?

A

Rapidly climbing PCO2, falling PaO2, decreased compliance

242
Q

List ddx of decreases in oxygenation in the PPV patient.

A

Loss of O2 supply, machine or circuit malfxn, worsening of underlying lung dz, new lung dz (pneumothorax, VAP, VALI, ARDS)

243
Q

List ddx of hypercapnia in the PPV patient.

A
  1. pneumothorax
  2. bronchoconstriction
  3. ET or TT obstruction
  4. Vent circuit issues (leak, exhale obstruction)
  5. Increased dead space (pulm)
  6. Inadequate vent settings
244
Q

List endotracheal techniques

A 
Laryngoscopic
Fiberoptic-assisted
Digital palpation
Nasal intubation
Retrograde intubation
Transillumination
Surgical technique (cricothyroidotomy)
Cricoid pressure
245
Q

What is a needle cricothyroidotomy?

A

Pass large bore catheter thru cricothyroid membrane to supply oxygen until can get a tube in; jet ventilation indication

246
Q

Complications of endotracheal intubation.

A 
kinking of tube
pressure induced tracheal necrosis
bronchial intubation
increased ICP
increased IOP
hypertension
tachycardia
247
Q

Indications for temp trach.

A

UA obstruction
oral/pharyngeal sx
long term ventilation
removal of tracheal FBs

248
Q

How big should trach tube be?

A

As big as will fit in trachea, measure on lateral cervical radiograph

249
Q

Describe the surgical technique for temp trach

A

GA, orotrach tube in place, dorsal recumbency, ventral cervical midline incision from cricoid cartilage to sternum, separate sternohyoid muscles along midline with blunt dissection and retract laterally, remove pertracheal connect tissue, transverse, vertical or box trach

250
Q

What needs to be avoided for temp trach?

A

recurrent laryngeal and tracheal blood supply

251
Q

Where do you make incision for transverse temp trach?

A

3-5 trach rings

252
Q

How is vertical temp trach done?

A

vertical incision thru 2-4 trach rings

253
Q

Trach tube care protocol

A
  1. Clean inner canula
  2. Humidify airway for 20 minutes before suctioning
  3. Always preoxygenate
  4. Sterile technique for suctioning, circular motion
  5. 100% O2 x 3 min after suction
  6. Suction 2-4 times (patient dependent)
  7. Replace cannula (q24h)
  8. Clean incision and ensure ties secure
254
Q

How is cyproheptadine thought to be helpful in feline asthma?

A

serotonin receptor antagoist that inhibits feline airway smooth muscle contraction

255
Q

Define spalling effect (pulm contusion).

A

lung injured directly by increase pressure, a shearing or bursting phenomenon that occurs at gas liguid interfaces and may disrupt alveolus at point of initial contact with shock waves

256
Q

Define inertial effec (pulm contusion)

A

occurs whn low density alveolar tissue stripped from heavier hilar structures as the accelerate at different rates

257
Q

Define implosion effect (pulm contusion)

A

Rebound or overexpansion of gas bubbles after a pressure wave passes, can lead to tearing of the pulm parenchyma fro excess distension

258
Q

Angiostrongylus vasorum

A

middle aged dog, parasitic infection, causes hemoptysis and pulm hemorrhage

259
Q

Define volutrauma

A

alveolar overdistension

260
Q

Define barotrauma

A

mechanical disruption of pulmonary tissues as result of pressure

261
Q

Define atelectrauma

A

Repetitive alveolar opening and collapse of alveoli

262
Q

Difference b/t VILI and VALI

A

Induced vs associated

VILI based on histopath, research setting

VALI clinical syndrome, live patients

263
Q

Why start heparin 3-4 d before warfarin?

A

Avoid hypercoagulable state thru inactivation of protein C with warfarin therapy

264
Q

Carboxyhemoglobin shifts OD curve to….

A

left

265
Q

Binding affinity of CO to Hgb

A

240X greater than oxygen

266
Q

3 possible outcomes from CO poisoning

A
  1. Complete recovery with transient hearing loss
  2. Recovery with permanent CNS effects
  3. Death
267
Q

Hydrogen cyanide gas effects

A

nonirritant but interferes with utilization of oxygen by cellular cytochrome oxidase, causing histotoxic hypoxia

268
Q

What gases can be inhaled during fire?

A

CO
Short-chain aldehydes (convert to acid in resp tract - oxides of sulfur and nitrogen)
Water soluble (ammonia, HCl)
benzene (from plastics)

269
Q

What reduces lung compliance from smoke inhalation?

A

alveolar atelectasis

pulmonary edema

270
Q

DDx for hyperemia in smoke inhalation

A
  1. carboxyHgb
  2. cyanide toxicosis
  3. systemic vasodilation
  4. local vasodilation from mucosal injury
271
Q

Reduction in a-v oxygen gradient may be suggestive of… (in smoke inhalation)

A

HCN toxicity

272
Q

Excessively high plasma lactate levels at admission are a sensitive indicator of ___ toxicity in humans (smoke inhalation)

A

HCN

273
Q

The half life of CO is about ___ minutes in patients with normal respiraotry exchange on room air, but is reduced to ___ to ___ minutes with an FiO2 of 100%

A

250 minutes

25-150 minutes

274
Q

How do you treat HCN toxicity?

A

IV sodium nitrite followed by IV sodium THIOSULFATE

Sodium nitrite may not be great for smoke inhalation b/c causes methemoglobinemia which will worsen O2 carrying capacity

275
Q

3 mechanisms for atelectasis

A

compression, oxygen adsorption, depletion of surfactant

276
Q

What is the primary collapsing force on the alveoli?

A

surface tension

277
Q

What are the four opposing distending forces of the alveoli?

A

transpulmonary pressure
tethering effect of surrounding structures
surfactant
gaseous nitrogen skeleton

278
Q

Why does adsorption atelectasis occur more rapidly in patients breathing oxygen enriched air?

A

Nitrogen skeleton is diminished or absent; the nitrogen skeleton usually provides support preventing collapse

279
Q

What lung lobes are thought to be more at risk of atelectasis based on higher pleural surface to volume ratio?

A

right middle, left upper lobe

280
Q

VAP definition

A

Pneumonia developed > 48 h after initiation of IPPV

281
Q

Sumner, JVECC, 2011. Deep oral swabs for pneumonia….findings.

A

No good for puppy pneumonia, community acquired pneumonia, 40-50% agreement with hospital acquired pneumonia.

282
Q

Compliance equals =

A

change in volume over change in pressure

283
Q

What are the 4 types of PV dyssynchrony?

A

trigger
flow
cycle (breath termination)
expiratory

284
Q

List the 4 types of hypoxia

A

hypoxic, anemic, stagnant, histotoxic

285
Q

Canine influenza strain

A

H3N8 - Greyhounds - Florida

Diagnosis difficult b/t viral shedding peaks during incubation 2-5 days, but when dogs become sick, not enough time for antibodies and viral isolation may be minimal b/c shedding decreased at this time

286
Q

Sepsis and SIRS cats, JAVMA, 2011, DeClue, findings:

A
  1. Sepsis: high bands, eosinopenia, hyponatremia, hypochloremia, hypoalbuminemia, hypocalcemia, hyperbilirubinemia
  2. When sepsis/SIRS compared = only * diff were bands and albumin
  3. Cats with sepsis * higher TNF than healthy cats and more likely to have detectable IL-6 than SIRS or healthy cats
  4. CXCL-8 not detectable in most cats
  5. No diff in mortality b/t sepsis or SIRS
  6. Variables correlated with nonsurvival in sepsis: IL-1B, IL-6, chloride
  7. Cats with SIRS had higher ALP
  8. # SIRS criteria fulfilled not associated with outcome
287
Q

DeClue, What mediators prominent in early vs. maintenance inflammatory phase?

A

TNF-a and IL-1B (early)

IL-6 and CXCL-8 (maintenance)

288
Q

SIRS criteria cats.

A

T103.5
HR 225
RR >40
WBC 19.5, or >5% bands

289
Q

Effect of oxyglobin in hypotensive cats, JAVMA, 2011, Wehausen.

A

SAP increased >80 mm Hg in 75% cats; increased >20 mm Hg above baseline in 29/33 cats, mean SAP during CRI 92

290
Q

Adverse effects oxyglobin hypotensive cats, JAVMA, 2011

A

respiratory changes, vomiting, pigmented urine (30/33 cats)

291
Q

Was NT-proBNP able to differentiate b/t CHF and nonCHF for moderate to severe pleural effusion in cats? Hassdenteufel, JVECC, 2013

A

Yes, cutoff 258 pmol/L

292
Q

What is airway pressure release ventilation?

A

Open lung ventilation, high CPAP maintained and patient allowed to breath spontaneously

293
Q

Most common causes of pneumomediastinum in cats (most common to least common)?

JVECC, 2013

A
  1. Endotracheal intubation and PPV
  2. Spontaneous
  3. Trauma
  4. Tracheal FB

50% had pneumothorax and pneumoretroperitoneum

22% had pleural effusion

From Flashcardlet (19 decks)

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