Pulmonary Flashcards
1
Q
Air confined to conducting airways. Mouth & nose –> terminal bronchioles
A
Anatomic dead space
2
Q
Alveoli that are ventilated but not perfused
A
alveolar dead space
3
Q
Anatomic + Alveolar dead space
A
Physiologic dead space
4
Q
Calculate physiologic dead space by comparing ratio of CO2 in arterial blood and exhaled gas
A
(Bohr equation)
5
Q
Bohr equation
A
Vd/Vt = (PaCo2 - PeCo2) / PaCO2
6
Q
alveoli that are ventilated but not perfused
A
alveolar dead space
7
Q
What is lung compliance?
A
change in volume / change in pressure
how easy it is to stretch something.
8
Q
Change in lung volume per unit of pressure change within lung when air is not moving
A
static compliance
9
Q
Change in lung volume per unit of pressure change within lung during air movement
A
Dynamic Compliance
10
Q
disease that causes increase in pulmonary complicance (Greater change in volume for a given pressure)
A
emphysema
11
Q
Disease that cause Decrease in pulmonary compliance (hard to inflate)
A
Fibrosis
Obesity
Vascular engorgement
Edema
ARDS
External compression
12
Q
increase in airway resistance (Factors that oppose inflation to lungs)
A
Static elastic recoil of lungs
Frictional resistance of lung tissues
Resistance to airflow
13
Q
volume of air remaining in the lungs after max expiration?
A
Residual volume
14
Q
max volume of air expired from the resting end expiratory volume
A
expiratory reserve volume
15
Q
max volume of air inspired from the resting end-inspirated level
A
Inspiratory reserve volume
16
Q
max volume of air inspired from end expiratory level
A
Inspiratory capacity
17
Q
max volume of air expired from the max inspiratory level
A
vital capacity
18
Q
volume of air remaining in lung after expiration
A
Functional residual capacity
19
Q
volume above residual volume where small airway close
A
closing volume
20
Q
absolute volume of gas in lung when small airways close.
A
closing capacity
21
Q
positions that increase dead space
A
Sitting position
neck extension
22
Q
increase volume of conducting zone
reduce pulmonary blood flow effect on dead space
A
increase dead space
23
Q
anything that reduces volume of the conducting zone or increases pulmonary blood flow. effect on dead space
A
decreases dead space
24
Q
if dead space increases, what changes to compensate?
A
TV, RR, minute ventilation to maintain constant PaCO2
25
positions that decrease dead space
Neck flexion
trendelenburg
supine
26
Blood gas values that cause pulmonary vasoconstriction to shunt blood to areas with more O2
Low PO2 & High CO2 (acidosis)
27
What causes Pulmonary vasodilation to pick up more O2
High PO2
Low CO2
28
Physiologic shunt
ARDS, pneumonia
29
Anatomic shunt
cardiac anatomy: TOF, CAVC, HLHS
Oxygen will not reverse this shunt.
30
what is the difference between PAO2 and PaO2 called?
A-a Gradient
31
3 Reasons A-a gradient isn't zero
Thebesian veins
bronchiolar veins
pleural veins
32
High A-a gradient
Shunt
V/Q mismatch
Diffusion defect
33
typical liters of ventilation per min
4L/min
34
typical liters of perfusion per min
5L/min
35
Typical V/Q ratio
0.8
36
37
simple definition of shunt
perfused but not ventilated
38
simple definition of dead space
ventilated but not perfused
39
PA>Pa>Pv
Zone 1
apex
dead space
lowest blood flow
V > Q
40
Pa>PA>Pv
Zone 2
Middle lobe
waterfall
medium blood flow
41
Pa > Pv > PA
Zone 3
Highest blood flow
V < Q
shunt
Base of lung
42
conducting zone
no gas exchange
43
Respiratory Zone
Gas exchange with the blood
Pulmonary circulation, not bronchial circulation
44
Type I pneumocytes
structural cells
45
Type 2 pneumocytes
produce surfactant
46
Type 3 pneumocytes
macrophages
47
Many things that Increase Dead Space
Facemask
heat & moisture exchanger
PPV
Anticholinergics
old age
Neck extension
decreased cardiac output
COPD
48
Decreased Dead Space
ETT
LMA,
Tracheostomy
neck flexion
49
conducting zone
upper airway to terminal bronchioles
50
Inspiration spontaneous breathing pressure and volume:
pressure decreases
volume increases
51
Anatomy of spontaneous breathing
External intercostals & diaphragm contract
Parietal & visceral pleura get pulled outward
52
Expiration spontaneous breathing pressure and volume
1 volume decreases
2 intra pleural and intraalveolar pressure increases
53
What values cause pulmonary vasoconstriction
Low oxygen
high carbon dioxide
acidosis
54
pulmonary vasodilation
High oxygen
low carbon dioxide
55
where does gas exchange occur?
across the flat epithelium of type 1 pneumocytes by diffusion
56
High O2 concentration in lungs
Higher affinity for hemoglobin binding
Loading of O2
57
PaO2 when hemoglobin is 50% saturated with oxygen
P50
Normal P50 = about 27 mmHg
58
Low O2 concentration in tissues
Low affinity for hgb binding
Unloading of O2
59
Oxyhem DIssociation Curcve Right Shift
release O2
MORE O2 TO THE TISSUES
LOWER P50
60
Causes of Right shift
Oxyhemoglobin curve
hypercapnia
hyperthermia
acidosis
Increased 2,3 DPG
61
Oxyhem DIssociation Curcve Left Shift
Love to hold O2
LESS O2 TO THE TISSUES
HIGHER P50
62
Causes of Left shift 02 dissociation curve
Hypocapnia
hypothermia
Alkalosis
Decrease 2,3 DPG
Hemoglobinopathies
Hgb F
63
The CO2 dissociation curve is much __________ and _____________
than is that for O2 dissociation curve
steeper and linear
64
Describes the relationship between PCo2 and total CO2 concentration in the blood
CO2 Dissociation Curve
65
CO2 curve right shift
releases co2
66
CO2 curve Left Shift
picking up CO2
67
Hypoxic
68
Where is central control located?
Brainstem (medulla/pons)
Cortex
Limbic System
Hypothalamus
69
Center of inspiration
Pacemaker of normal rhythmic breathing
Dorsal Respiratory Group
70
Holds most neurons in nucleus of the tractus solitarius (NTS)
dorsal portion of the medulla
71
Sensory termination of glossopharyngeal &
vagus nerve
NTS
72
transmits information to NTS
1. Peripheral chemoreceptors
2. Baroreceptors
3. Receptors in liver, pancreas, GI tract
4. Receptors in lungs
73
Contains neurons controlling chiefly expiration & activated
during forceful breathing
Ventral Respiratory Group
74
Pneumotaxic Center location
Pons
75
Apneustic Center Location
pons
76
Inhibitits apneustic center for inspiration
Fine tunes respiratory pattern
Controls respiratory rate and depth of breathing
Pneumotaxic Center inhibits the dorsal group
77
Stimulates inspiratory center (dorsal group)
apneustic center
78
center inhibited by J receptors
Apneustic center
apneustic doesn't love to jam
79
where are central chemoreceptors located
The ventral respiratory center in the medulla
80
central chemoreceptors respond to
changes in pH in CSF, which in turn are caused by diffusion of CO2 from brain capillaries
81
peripheral chemoreceptors respond to
reduced PO2 and increases in PCO2 and H+ concentration
82
where are peripheral chemoceptors located
carotid bodies
Transverse aortic arch
83
what do the carotid bodies respoond to
mainly PaO2, but also CO2 & pH (H+)
84
what does the peropheral chemoreceptors detect?
mainly O2, but also CO2, pH (H+) changes
85
what does central chemoreceptors detect?
High H+
High CO2
86
peripheral chemoreceptor whos Afferent nerve --> vagus nerve --> dorsal medullary respiratory area
Aortic bodies
87
Afferent nerve fibers pass through Hering’s nerves --> glossopharyngeal nerve
--> dorsal respiratory area of the medulla
Carotid bodies
88
Reflex where Sensory nerves within the lungs discharge in response to lung distension (stretch)
Hering-Breuer Reflex
89
increase in expiratory time & slows respiratory rate, switches off inspiratory ramp
stops overinflation
Hering-Breuer inflation reflex
90
increased ventilation when lungs deflated abnormally, such as in pneumothorax, or it may have a role in the periodic spontaneous deep breaths (sighs) that help to prevent atelectasis
prevents atelectesis by stimulating a deep breath
Hering-Breuer deflation reflex
91
location of J receptors
alveolar walls close to capillaries
92
what do J receptors look like
Endings of unmyelinated C fibers
93
What causes Stimulation of J receptors
rapid, shallow breathing or complete apnea
94
Associated with: pulmonary edema, pulmonary embolism, CHF, interstitial lung disease
"Jam" Traffic
J receptors
95
where do irritant receptor impulses go
Impulses travel up the vagus in myelinated
fibers
96
Reflex of irritant receptor
bronchoconstriction hyperpnea
97
hypoxic ventilatory response
PaO2 less than 60 triggered in carotid body chemoreceptor to increase minute ventilation
98
What impairs hypoxic ventilatory response
Anesthetics
Carotid endardarectomy
99
In what way does carotid endarterectomy shift CO2 curve?
Left shift
100
T or F ? Bilateral carotid endarterectomy would result in significant impairment of the hypoxic drive.
True
101
Actional potential along Hering's nerve stimulates central controller to increase minute ventilation
Hypoxic Ventilatory Response
102
involuntary ventilation
medulla
pons
103
voluntary breathing
cortex
104
Values that inhibits respiration
low h+ (alkalosis)
low PaCO2
105
What effect does PaO2 <60 have on the body?
overcomes respiratory inhibition
(low H and Low PaCO2) in peripheral chemo receptors (Glomus cells)
106
the rate of diffusion of a gas through a tissue sheet is proportional to the area of the sheet and the partial pressure difference across it, and inversely proportional to the thickness of the sheet
Ficks Law
107
How does Hypoxic Pulmonary Vasoconstriction effect blood flow
Reduces the blood flow to poorly ventilated regions of the lung
108
The PO2 of the alveolar gas, not the pulmonary arterial blood, chiefly determines the response.
This response does NOT depend on central nervous connections.
HPV (HYPOXIC PULMONARY VASOCONSTRICTION)
109
This protective mechanism causes vasoconstriction in poorly ventilated areas of the lung to stop shunting.
Often, during atelectasis or one-lung ventilation
hypoxic pulmonary vasoconstriction
110
5 causes of hypoxemia
1 Atmosphere (high altitude)
2. Hypoventilation
3. Diffusion limitation
4. Ventilation-perfusion inequality
5. Shunt
111
Impaired movement of oxygen from alveoli to pulmonary vasculature
Diffusion Limitation
INCREASED A-a gradient
112
causes of diffusion limitation
Thickening of alveolar capillary
Pulmonary fibrosis
Emphysema
Interstitial lung disease
113
two causes of hypercapnia
hypoventilation
Vq mismatch
114
The maximum amount of hemoglobin that can be bound
O2 capacity
115
Most CO2 in the blood is in the form of what?
Bicarbonate
116
preset inspi pressure over predetemined time
Pressure Control Ventilation
117
Mode on vent where Inspiratory pressure varies based on compliane
volume control ventilation
118
Inspiratory flow starts high then decreased
pressure control
119
inspiratory flow is held constant
Volume control
120
7 vent modes that can be used on a spontanously breathign patient
AC
APRV
BIPAP
CPAP
Manual
PSV/PSV pro
SIMV
121
Bicarbonate leaves RBC and chloride
enters to maintain neutrality
Hamburger shift
122
what transports CO2
1 Bicarbonate ions (70-90%)
2 Dissolved in plasma (5-10%)
3 Carbamino compounds: combined
with amino acids (5-20%)
123
CO2 combines with H2O to form
carbonic Acid H2CO3
124
Carbonic Acid H2CO3 dissolved into
bicarbonate (HCO3) and hydrogen
125
The effect that says that oxygen causes hemoglobin to RELEASE CO2
Haldane Effect
Describes CO2 carriage
126
Effects that says CO2 and hydrogen ions cause conformational change in Hgb that favors release of oxygen
Bohr Effect
describes OXYGEN carriage
127
calculates physiological dead space
Bohr Equation = Vd/Vt
128
what does bohr equation compare to
PP of CO2 in blood vs PP of CO2 in exhaled gas
129
what is the normal Vd/Vt ratio?
150mL/450mL= 33%
130
In the presence of oxygenated hemoglobin, the CO2 curve shift to the ________.
right
131
in the presence of deoxygenated hemoglobin, the CO2 curce shifts to the __________.
left
132
Hypercapnia AKA Hypercarbia
PaCo2 >45
increase in SNS response --> Increase BP
133
What happens during a laryngospasm?
iSLN is stimulated (vagus)
lateral cricoarytenoids adduct
thyroarytenoids lengthen
These muscles close the glottis by adducting the vocal cords.
