final review Flashcards
(114 cards)
1
Q
Where is the larynx located at birth? Adult?
A
Birth - C3-C4
Adult - Anterior C3-C6
(between pharynx and trachea)
2
Q
What is normal A-O extension?
A
35 degrees
3
Q
Name the Mallampati classes
A
Class. 1: full view of uvula and tonsillar pillars, soft palate
Class. 2: partial view of uvula or uvular base, partial view of tonsils, soft palate
Class. 3: soft palate only
Class. 4: hard palate only
4
Q
Airway Innervation
Sphenopalatine ganglion
A
Middle division CN 5
nasal mucosa, superior pharnx, uvula, tonsils
5
Q
Airway Innervation
Glossopharyngeal nerve
A
CN 9
(lingual back 1/3, pharyngeal, tonsillar nerves)
oral pharynx, supraglottic region
6
Q
Airway Innervation
Internal branch Superior Laryngeal nerve
A
CN 10
mucus membrane above the VC’s, glottis
7
Q
Airway Innervation
Recurrent Laryngeal nerve
A
CN 10
Trachea below vocal cords
8
Q
The SLN splits into what two nerves?
A
Internal SLN
External SLN
9
Q
Internal SLN provides ______ to supraglottic & ventricle compartment,
A
Sensation
10
Q
What does stimulation of the internal SLN cause?
A
Laryngospasms
11
Q
External SLN provides _____ innervation of cricothyroid muscle
A
Motor
12
Q
Vagus Nerve is CN ___, the LEFT RLN passes at the ________, provides _______ information to the infraglottis, and provides _____ innervation to all larynx muscles except _______
A
10 aortic arch sensory motor cricothyroid muscle
13
Q
Stimulation of the RLN causes
A
abduction of the VC
14
Q
Damage to the RLN causes
A
VC adduction
15
Q
How is a Childs larynx different than an adults?
A
A Childs larynx is cone shapes narrowing inferiorly
16
Q
The trachea is a flexible cylindrical tube supported by 20-25 ______ cartilages
A
C-shaped
17
Q
The carina (level T5-7) divides into 2 bronchi @ _____ from teeth
A
25cm
18
Q
Bronchials have ____ smooth muscle
A
thick O
19
Q
__________ transmits motor stimulation to diaphragm
A
Phrenic nerve (C 3,4,5)
20
Q
Intercostal nerves (T 1-11) send signals to the ____________
A
external intercostal muscles
21
Q
The act of inhaling is what type of ventilation?
A
negative pressure ventilation
lungs expand passively as pleural pressure falls
22
Q
How does the diaphragm move with inspiration and expiration?
A
inspiration - diaphragm moves down
Expiration - diaphragm moves up
23
Q
Explain Tidal Volume
A
volume of air inspired/expired during normal breathing (~500ml)
24
Q
Explain Inspiratory Reserve Volume
A
Maximum volume of air inspired from resting end-inspiratory level
25
Explain Expiratory Reserve Volume
maximum air expired from resting end-expiratory
26
Explain Residual Volume
Volume of air remaining in the lungs after maximum expiration (~1200)
27
Explain Inspiratory Capacity
maximum volume of air inspired from end-expiratory
28
Explain Vital Capacity
Maximum volume of air expired from maximum inspiratory level
29
Explain Functional Residual Capacity
volume of air remaining in lungs at end-expiratory
30
Explain Total Lung Capacity
volume of air in lungs after maximal inspiration
31
Remember: A capacity is always a sum of certain lung volumes.
What is FRC?
FRC = ERV + RV
2.5L
32
REMEMBER: Spirometry cannot measure ___________ thus ____________ and ____________ cannot be determined using spirometry alone.
Residual Volume (RV)
Functional Residual Capacity (FRC) and Total Lung Capacity (TLC)
33
How can FRC and TLC be measured? (3)
1) Helium dilution
2) Nitrogen washout
3) body plethysmography
34
In flow volume loops, where is the inspiration and expiration?
inspiration bottom half
| expiration top half
35
What are some functions are surfactant?
Lowers surface tension of alveoli & lung
Promotes stability of alveoli
Prevents transudation of fluid into alveoli
36
Pousilles law, Radius is to the 4th power.
* **reducing r by 16% will _________
* **reducing r by 50% will _________
double the R
increase R 16-fold
(major site of resistance is medium sized bronchi - 7th division)
37
```
Pressures
RA
RV
PA
Pulm Capillaries
LA
LV
Aorta
```
```
RA 3-5
RV 25/0
PA 25/8 (mean 14)
Pulm Capillaries 10.4
LA 8
LV 120
Aorta 120/80 (mean 90)
```
38
What are 2 mechanisms that decrease PVR?
recruitment - opening of previously closed vessels
| Distention - increase caliber of vessels
39
What is capillary volume at rest? maximal volume?
rest - 70 ml (1 ml/kg body weight) normal volume at rest
maximal - 200 ml
40
normal alveolar PO2
| normal alveolar PCO2
100
| 40
41
Inspired air PO2/PCO2
PO2 150/PCO2 0
42
Venous blood PO2/PCO2
PO2 40/PCO2 45
43
Pulmonary blood flow:
| Explain zone 1
@ Apex
PA>Pa>PV (Alveolar pressure collapses both artery & vein)
ventilated but not blood flow = no gas exchange
44
Pulmonary blood flow:
| Explain zone 2
Middle
Pa>PA>PV (intermittent opens with systole, closes with diastole)
45
Pulmonary blood flow:
| Explain zone 3
Base
Pa>PV>PA
Most ideal (optimum gas exchange and blood flow)
You can convert entire lung to zone 3 with exercise
46
Using positive pressure ventilation increases zone
2
47
V/Q mismatch improves as you move
down the lung
48
PVR: vasoconstrictors
reduced PAO2
Increased PCO2
Histamine
Thromboxane A2
49
PVR: vasodilation
Increased PAO2
Nitric Oxide
Prostacycline
50
Explain hypoxic pulmonary ventilation
HPV is produced by alveolar hypoxia
Localized response of the pulmonary arterioles
Shift of flow to better ventilated pulmonary regions - balances V/Q ratio
opposite reaction than systemic circulation to hypoxia
51
normal CO2 production at rest
200ml/min.
52
Normal PO2 at rest
250 ml/min
53
When is alveolar air expired?
at the end of exhalation
1st - dead space
2nd - mixed dead space and alveolar air
3rd - alveolar air
54
What is Ficks Law?
What is normal Oxygen consumption
method of determining CO, blood flow throw lungs/min
VO2 @ rest = 300ml/min
55
normal V/Q ratio
Ventilation 4L/min / Perfusion 5L/min
or 0.8
56
What is a shunt
perfused but not ventilated
Blood is being shunted from pulmonary artery to pulmonary vein without participating in gas exchange in lungs
57
In a physiologic shunt, V/Q is ____ normal
below
58
In dead space, VQ is ______ than normal
greater
59
Dead space =
ventilated but not perfused
When physiologic dead space is great much of work of breathing is wasted effort because ventilated air does not reach blood
60
What is rough rule sats and PAO2
PaO2: 40,50,60 for Sat.: 70,80,90
61
What is mixed venous blood in PA?
| What is the HB P50 point
40
| 27
62
explain HBG-O2 affinity when shifted to left and right
left - Hb has higher affinity for O2
| Right shift - Hb has less affinity for O2
63
Causes of a right shift
```
Acidosis (High H) (Bohr effect)
High PaCO2
Fever (High temp)
High 2,3 DPG
High metabolism
Exercise
```
(H’s!!!)
64
Causes of a left shift
```
ALkolosis (low H)
Low PaCo2
Hypothermia (coLd)
Low 2,3 DPG
methnomoglobin
```
(L’s)
65
O2 content in the blood is the sum of O2 carried on ____ and dissolved in _____
HGB
| plasma
66
What is the equation for O2 content?
CaO2 = (SO2 * [Hb] * 1.31) + (PO2 * 0.003)
67
Most CO2 is transported as
bicarb (70%)
68
The dorsal respiratory group (DRG) controls _____ & ______. The _____ & _____ deliver sensory information to the DRG. The DRG receives signals from 3 sources:
inspiratory and expiratory
Vagal (X) & Glossopharyngeal (IX)
Peripheral chemoreceptors
Baroreceptors
Lung receptors
69
The Chemo-sensitive area of the brainstem located on the ________. It responds to changes in
ventral medulla surface
PCO2 or H ion concentration
70
CO2 is highly permeable to the BBB so blood and brain concentrations are
equal
71
Release of H ions in the brain stimulates
respiratory center activity
72
Pco2 changes rapidly cause change in rate of pulmonary ventilation. Drastic increase in _____ caused by increase in Pco2
ventilation
73
Peripheral chemoreceptors are located in _____ & _____
carotid and aortic bodies
74
In peripheral chemoreceptors, ______ nerve fibers pass via _____ to act on DRG
afferent
CN IX
75
In peripheral chemoreceptors, aortic bodies from _____ to DRG
CN X
76
Peripheral chemoreceptors are stimulated by ______. Impulse rate is sensitive to drops in PaO2 from a range of ___ mmHg to ___ mmHg (hypoxia)
hypoxemia
60 to 30
77
High Risk PFT results (4)
FEV1 < 2L
FEV1/FVC < 0.5
VC < 15cc/Kg in adult & < 10cc/Kg in child
VC < 40 to 50% than predicted
78
```
Intubation Criteria:
Mechanics - 3
Oxygenation - 2
Ventilation - 2
Clinical - 6
```
Mechanics: RR>35, VC <15cc/Kg in adult or <10cc/Kg in child, MIF more neg. than -20cmH2O
Oxygenation: PaO2 < 70mmHg on FiO2 of 40%, A-a gradient > 350mmHg on 100% O2
Ventilation: PaCO2 > 55 (except in chronic hypercarbia), Vd/Vt > 0.6 (remember normal dead space is 30%)
Clinical: airway burn, chemical burn, epiglottitis, mental status change, rapidly deteriorating pulmonary status, fatigue
79
Extubation criteria
VSS, awake & alert, resp. rate < 30
ABG on FiO2 of 40% PaO2 >70 and PaCO2 <55
MIF is more negative than -20cm H2O
Vital capacity (VC) > 15cc/Kg
80
Normal ABG values
```
pH: 7.35 – 7.45
PCO2: 35 – 45 mmHg
PO2: 75 – 105 mmHg
Bicarbonate: 20 – 26 mmoles/L
Base excess: -3 to +3 mmoles/L
```
81
*Rule: an increase of PCO2 by 10 mmHg causes a _____ in pH by ___, likewise, a decrease of PCO2 by 10 mmHg will _____ pH by ______
decrease 0.08
increase 0.08
(opposites)
82
What is an A-a gradient, what is a rough rule for measurement
a measure of efficiency of lung
| age/3
83
What is the treatment for an large A-a gradient
Tx is supplemental O2, adjust ventilation, tx atelectasis, add PEEP, TREAT UNDERLYING CAUSE
84
Rule: a decrease in bicarb by 10 mmoles _______ the pH by 0.15, likewise, an increase in bicarb. By 10 mmoles ______ pH by 0.15
decrease 0.15
increase 0.15
(same)
85
What is Total body bicarb. deficit =
What do you replace?
(base deficit * wt in Kg * 0.4), in mEq/L, usually replace ½ of deficit
86
T/F: Pulse Ox is mandatory intraoperative monitor
true
87
What is infrared and red light in pulse ox
infrared - 940nm, oxyhemoglobin absorbs more of this light, corresponds to 100% sat
red - 660nm, deoxyhemoglobin absorbs more of this light, corresponds to 50% sats
88
Carboxyhemoglobin (COHb) – from CO poisoning is viewed as oxyhemoglobin by pulse ox. and shows a SpO2 of ____, this is an overestimation of the true oxygenation, co-oximeter used to distinguish between the two
100%
89
Causes of methemoglobin
nitrates, nitrites, sulfonamides, benzocaine (hurricane spray), nitroglycerine (NTG), nitroprusside (SNP)
90
methemoglobin absorbs equally at both wavelengths, 1:1, shows a SpO2 of
85%
91
How os methemoglobin treated
low dose methylene blue or ascorbic acid
92
Does fetal HGB and bilirubin affect pulse ox?
no
93
```
Capnography:
AB
BC
CD
DE
What is D?
```
```
AB - begin. exhalation (dead space gas)
BC - exhale dead space and alveolar gas
CD - alveolar plateau
DE - inspiration
What is D? - highest CO2
```
94
In the awake and lateral position, the dependent lung is
better perfused and ventilated
95
What are some things that favors the upper lung?
Positive pressure ventilation
Muscle paralysis
Rigid bean bag
open PTX of upper lung
96
Factors that inhibit HPV
hypocapnea,
Vasodilators: nitroglycerin (NTG), nitroprusside (SNP), b-adrenegic agonists (dobutamine), calcium channel blockers
inhalation agents
97
Hypoxia during one lung ventilation
* FIO2 of 0.8 to 1.0
* Check tidal volumes – want 10cc/Kg, suction ETT
* Fiberoptic scope to ensure proper ETT placement
* Adjust RR to keep PaCO2 at 40mmHg
* Add 5cm H2O CPAP to nondependent lung – warn surgeon
* Add 5cm H2O PEEP to dependent lung – tx’s atelectasis but may increase vascular resistance
Increase both CPAP and PEEP slowly
* Ask surgeon to clamp or ligate nondependent PA
* Return to two lung ventilation always an option
98
What triggers MH?
```
Inhalation agents (not N2O)
succs
```
99
The ________ receptor (Ca release channel) fails in the sarcoplasmic reticulum leading to decreased ___ reuptake from within the cell (myocyte) causing a 500-fold increase in intracellular Ca, leading to sustained muscle contraction, glycolysis, and heat production.
ryanodyne
Ca
100
Abnormal _________ coupling results in prolonged and irreversible muscle contracture.
excitation-contraction
101
Most sensitive sign of MH
| Most specific sign of MH
```
Unexplained Tachycardia
Increasing EtCO2 (2-3X)
```
102
Other intra-op signs of MH
decrease in SaO2 & SpO2,
rigidity despite muscle relaxant onboard, dysrhythmias,
tachypnea,
cyanosis,
sweating,
unstable BP,
mottling of skin,
trismus (masseter spasm) after succinylcholine,
darkening of blood in surgical field, decreased mixed venous saturation,
cola-colored urine,
heating and exhaustion of CO2 absorber, hyperthermia
103
Labs for MH
initial metabolic acidosis then a combined metabolic & respiratory acidosis, hyperkalemia,
hypercalcemia,
hyperphosphatemia,
creatinine kinase (CK) > 1000 IU, myoglobinuria,
hypoxemia
104
Factors that increase MAC
```
Age: term infant to 6 months of age has the highest MAC requirement****
Hyperthermia
Chronic EtOH abuse***
Hypernatremia
Drugs that increase CNS catecholamines
```
105
Factors that decrease MAC
```
Hypothermia: for every 1 deg. C drop in body temp – MAC decreases 2 to 5%
Preop medications
IV anesthetics, opioids
Neonate/Premature infants
Elderly
Pregnancy***
Acute EtOH ingestion
Lithium
Cardiopulmonary bypass (CPB)
Hyponatremia
Alpha 2 agonists
Calcium channel blockers
Severe hypoxemia – PaO2 < 38 mmHg
```
106
Factors that have no effect on MAC
```
Thyroid gland dysfunction
Duration of anesthesia
Gender
Hyper/hypokalemia
Hyper/hypocarbia
```
107
What is the second gas effect
The ability of a large volume uptake of a first gas (N2O) to accelerate the rate of rise of the alveolar partial pressure of a concurrently administered companion gas (agent) thus speeding induction
108
What is diffusion hypoxia
This results from the dilution of alveolar O2 concentration by a large amount of N2O “outgasing” or leaving the pulmonary capillary blood at the conclusion of N2O administration
Rapid desaturation can be seen, especially with a concurrently decreased FRC: pregnancy, obesity, children
109
How do you avoid diffusion hypoxia?
Don’t extubate while on 70% N2O
Avoided by administering 100% O2 following N2O use
110
Nicotine stimulates _____ ______ – catecholamines released from adrenal medulla – increasing HR, BP, and SVR – persists ___ minutes after last cigarette
sympathetic ganglia
| 30
111
If pt is a smoker, Pre-O2 well and avoid instrumentation of airway until
deep level of anesthesia
112
Advise stopping at least ___ hours prior to surgery
12
113
Cessation of > __ weeks will reduce post-op pulmonary complications
8
114
In COPD patients to avoid bronchospasm, what should you do?
avoid *histamine releasing drugs
Pentothal (STP), Morphine (MSO4), Atracurium, Mivacurium, Neostigmine
Tx with nebulized albuterol especially before extubation
