Chest Flashcards
Which is false for ventilation?
A. Elastance is the degree to which the lung can return to its dimensions (recoil) after removal of the distending forces of inspiration
B Compliance is a measure of lung distensibility and is the reciprocal of elastance
C Alveolar surface tension is low due to surfactant produced by type I alveolar cells which lowers surface tension, prevents collapse of small alveoli, and reduces work to inflate lungs.
D Contributors to inspiratory airway resistance during normal respiration include the nares (79% of total resistance during inspiration), larynx (6%), and small airways (15%).
C type II
What is false regarding transport of gas?
A Oxygen is transported in a dissolved state or with hemoglobin (Hb), the amount of dissolved oxygen is not sufficient to maintain adequate peripheral tissue oxygenation.
B One gram of pure Hb can combine with 1.39 mL of O2, normal blood has ~ 15 g of Hb/100 mL.
C O2-Hb dissociation curve (sigmoid form), the steep part of the curve means that the peripheral tissues can withdraw a large amount of oxygen for only a small decrease in capillary oxygen partial pressure
D The oxygen dissociation curve can be shifted to the left with acidosis and increased temperature, 2,3-diphosphoglycerate in red blood cells (RBCs), and CO2
A majority Hg bound (98.5%)
B equivalent to 20.8 ml of oxygen/100ml of blood
C flat upper means decrease in partial pressure O2 will have little effect > 80 mmHg
ANSWER
D false b/c shift RIGHT
Which of the following is true regarding CO2 in the body?
a. Approximately 10% of arterial CO2 is carried in the blood in the dissolved form
b. Approximately 20% of CO2 is carried as bicarbonate
c. The majority of CO2 is carried as carbamino compounds (primarily hemoglobin)
d. The Haldane effect refers to the effect of changes in oxyhemoglobin saturation on CO2 content in relation to PCO2
D true
A 5% dissolved
B majority in bicarb
C 20% of excreted CO2 as carbamino compound
5% dissociated
True or false HIGH V/Q mismatch is seen with atelectasis, pneumonia, and severe pulmonary edema?
False – this describes low V/Q; high is seen with PTE
What are 5 causes hypoxemia?
hypoventilation, low FiO2, diffusion impariement, V/Q mismatch, shunting
Which is true?
A The right cranial lung lobe projects further cranial than the left
B The diaphragm crura arise from tendons from L3
C The skin of the dorsolateral thorax is supplied by the costal arteries
D Ribs 1-9 articulate with the sternum
D true
A left is further cranial
B L4 diaphragmatic crura
C. skin thoracodorsal a
Which is true?
A The latissimus dorsi pulls the shoulder dorsally.
B The scalenus inserts on the 6th rib.
C Branches of the internal thoracic artery and vein perforate between the right and left deep pectoral muscle.
D The internal thoracic artery travels caudal to the transverse thoracic muscles.
C true
A caudally
B 5th
D internal thoracic a. is dorsal to transverse thoracic m.
What is true thoracic wall?
A Brachiocephalic arteries give rise directly to the internal thoracic arteries
B Subclavian veins drain into the cranial vena cava
C The internal thoracic artery will be avoided if an incision stops at the lateral aspect of the transverse thoracic muscle
D Intercostal arteries are all branches from the aorta
C true
A subclavian –> internal thoracic
B. brachicephalic veins —> Cr VC
D first 3 or 4 branches come from thoracic vertebral artery
Pick the true.
A. A transdiaphragmatic approach give you best access to the right ventricle
B A left intercostal approach allows visualization of left side of the left side of the heart, the azygous vein, and the right ventricular outflow tract and pulmonary artery
C The vena cava can be identified from a right lateral, ventral, and left lateral approach
D In a dog with PRAA, a right intercostal approach is best
C true
A left ventricle
B right thoracotomy: azygous
right ventricular outflow and pulmonary artery are Left (plus a ventral approach)
D PRAA left intercostal best
(typically sx of esophagus and trachea from the right)
T/F: When the thoracic volume is less than V(0), a net inward passive recoil of the thoracic wall is created.
false: OUTWARD
V(0) is when the passive elastic structures of the thoracic wall are relaxed, so less volume brings everything in, and it wants to expand back out to normal
Which of the following is true regarding the thoracic duct and thymus?
A. The thoracic duct travels dorsolateral to the on the left in dogs and on the right in cats
B. It crosses to the right in dogs at the 5th or 6th thoracic vertebrae
C. The thymus continues to grow until 7-8 months of age, at which time it begins to involute
D. The thymus is derived from the third pharyngeal pouch
A caudal thorax: right in dogs and left in cats
B crosses left at T5/6
C grows until 4-5 mo of age, then involutes
D TRUE
Which of the following is false regarding the anatomy of the pleural space?
A. The normal pleural space is lined by a single layer of mesothelial cells
B. Pleural fluid is normally 0.1ml/kg in dogs and 0.3ml/kg in cats
C. The parietal pleura consists of two portions, the costal and mediastinal
D. The plica vena cavae is a thin reflection of pleura onto the caudal vena cava
C* Three portions, costal, mediastinal and diaphragmatic
True or false: the volume of air remaining in the lungs at the end of normal exhalation is known as functional residual capacity. This represents the point at which all forces, including collapse of the lungs, expansion of the chest cavity as in passive equilibrium.
True
When sanguineous pleural effusion is iatrogenic from a lateral thoracotomy approach what is/are the possible source (s)?
intercostal, internal thoracic a
What are the protein contents and cell counts for exudate, modified transudate and transudate?
E: >3 g/dL; >7000 cell/uL
MT: >2 but ≤5 g/dL; >1500 but ≤7000 cell/uL
T: ≤2.5 g/dL; ≤ 1500 cell/uL
Definitive diagnosis of chyle is made by comparing serum ______ and _______ concentrations with those of the effusion.
triglyceride and cholesterol
T/F With chyle, triglyceride concentration is lower and cholesterol higher in the effusate compared with serum.
False; TG HIGHER and cholesterol lower
Intrapleural volumes of air up to __ mL/kg cause no clinical signs in healthy dogs and resorb spontaneously within approximately __ weeks.
45 ml/kg
2 weeks
Radiography is a sensitive diagnosing pleural fluid even when volumes are small: as little as ____ mL of fluid in a dog and ___ mL in a cat.
dog 100
cat 50 ml
What type of muscle is the trachealis muscle and what does it connect?
transversely orientated smooth m
external surfaces of tracheal rings
What is the main innervation of the trachea mucosa and trachealis m?
right vagus and recurrent laryngeal nerve
What is the typical mucociliary flow rate? What hinders speed and efficacy?
10-15 mm/min in dogs
increasing particle size, escalating mucus viscosity
True or false: The Intercostal veins drain into the azygous, except for 1st 3 intercostal spaces, which go to costocervical vein
false: only 1st –> costocervical, rest azygous.
costocervical trunk –> first intercostal a –> 1st 3 intercostal spaces
aorta –> rest of intercostal arteries
Find the false
A Respiratory tree: Trachea -> mainstem bronchi -> lobar bronchi ->segmental bronchi -> subsegmental bronchi -> terminal bronchioles -> respiratory bronchioles -> alveolar ducts -> alveolar sacs -> pulmonary alveoli
B Arterial supply to bronchus is bronchial arteries from bronchoesophageal artery
C Right lung is divided into: Right cranial, Right middle, Right caudal and Accessory lung lobe
D Left lung, left cranial and caudal, caudal has cranial and caudal segments
D Left lung: left cranial (cranial and cd. segments) and caudal
Where does CO2 affect ventilation?
central chemoreceptors on medulla
peripheral receptors in carotid and aortic bodies
What are (4) causes of hypoxemia responsive to supplemental O2?
hypoventilation, low FiO2, diffusion impairment (very)
+ increased V/Q
When to provide supplemental oxygen?
arterial saturation < 93-95%
and/or PA-aO2 gradient > 20 mm Hg
What is the peak inspiratory pleural pressure in anesthetized dogs
-7 to -14.3 cm H2O
What agent is used in ether clearance test to evaluate for chylous effusion?
potassium hydroxide alkalinizes samples
What is the width to height ratio of the canine trachea
normal = 1:1
Tracheal size does NOT increase proportionately with the size of the dog
What percentage of adult trachea can you remove? juvenile trachea?
50-58% adult tracheal length
20-25% of length in puppies
juvenile trachea withstands only 60% of the force of adult trachea
What level of tension is tolerated by the trachea
> 7.5N stenosis invariably results;
7.2N-21.4N (720- 2140 g) did NOT produce tracheal avulsion even though tension relieving sutures not used in sheep tracheas
what percent luminal stenosis (trachea) produces clinical signs?
50-75%
What are the partial pressures of oxygen in the nasal cavity? arteries? veins? intracelluar fluid?
N 160mm Hg A 90-95 mmHg V 40 mm Hg I 10 mm Hg LARGE gradient
what are the pressure gradients for CO2 in alveolar air? arteries? veins? Tissues?
Al 40 mm Hg Ar 40 mm Hg V 46 mm hg T 50 mm Hg small gradient
What is normal V/Q?
0.8-0.9 (a little more perfused than ventilated)
What is hypoxic pulmonary vasoconstriction?
diverts blood away from under ventilated areas in conscious animals
What are the effects of PTE on ventilation?
hypoxemia, hypocapnia, increased alveolar-arterial gradient on room air
What is the side effect of PEEP on physiology of respiration/CV (4)?
hyperinflation –> inc vagal tone –> slower heart rate
decreased venous return
increase in right ventricular afterload (pulmonary vascular resistance)
decrease LV afterload (pressure differential, body still atmospheric)
What is difference between IPPV and PEEP?
IPPV is conventional positive ventilation, PEEP maintains + presssure in expiration
what should the I:E ratio be when ventilating?
< 1:2
inspiratory time = 1- 1.5 sec
If alveolar ventilation decreases by 50% then PaCO2 ___
increases by 2x
PaCO2 and Va are directly and inversely related
True/false: Pulmonary ventilation = minute ventilation
false: a large portion of inspired air fills respiratory passage
minute ventilation = tidal volume x resp rate
In what direction does fluid flow in the pleura space?
•Pleural fluid production is favored
•Absorption of fluid across parietal and visceral pleura
oParietal → space → visceral pleural lymphatics and capillaries
What is a breathing pattern characterized by cycling between hyper and hypo ventilation?
Cheyne-stokes
What is a deep and labored breathing that is a form of hyperventilation?
Kussmal respiration
What breathing pattern is caused by damage to pons or upper medulla and results in a hold at end inhalation?
Apneustic respiration
where do arteries and veins lie in relation to bronchi
pulmonary arteries = cranial dorsal aspect
Pulmonary veins = caudoventral
how many ribs can you safely remove?
6
what are some products of the thymus?
thymosin, thymic humoral factor, thymopoietin, thymostimulin and thymulin involved in T-cell enhancement and maturation of immature T-cells
Fick’s law = Rate of transfer of a gas through a sheet of tissue is proportional to the …
SA available for diffusion
Diffusion coefficient of the gas
Difference in gas partial pressure
• Inversely proportional to the tissue thickness
Starling law=
differences of pressure on net filtration
K x {[(HPc parietal -HPc visceral)]
What muscles can be activated to aide the diaphragm in inspiration?
“external intercostal, sternocleidomastoid, scalenus, and ventral serratus muscles are used to pull the ribs in a rostral direction and pull the lungs outward”
