Final Exam Review Flashcards
1
Q
Adult larynx anatomic location
A
Anterior to C3-C6
2
Q
At birth larynx anatomic location
A
C3-C4
3
Q
Larynx lies between ___ and ___
A
Pharynx and trachea
4
Q
Normal A-O extension
A
35 degrees
5
Q
Mallampati Classification
A
Pt sitting, neck extended, mouth fully opened, tongue protruded, no phonation
MP Classes 1-4
6
Q
MP Class 1
A
Full view of uvula and tonsillar pillars, soft palate
7
Q
MP Class 2
A
Partial view of uvula or uvular base, partial view of tonsils, soft palate
8
Q
MP Class 3
A
Soft palate only
9
Q
MP Class 4
A
Hard palate only
10
Q
Sphenopalatine ganglion—middle division of CN ___ and innervates what 4 structures?
A
Middle division of CN V
- Nasal mucosa
- Superior pharynx
- Uvula
- Tonsils
11
Q
Glossopharyngeal nerve innervation
A
CN IX
- Posterior 1/3 of tongue
- Pharyngeal, tonsillar nerves
- Oral pharynx
- Supraglottic region
12
Q
Internal branch of superior laryngeal nerve
A
CN X
- Mucus membrane above the vocal cords
- Glottis
13
Q
Recurrent laryngeal nerve
A
CN X
-Trachea below the vocal cords
14
Q
Superior laryngeal nerve is a branch of what cranial nerve?
A
Vagus nerve (CN X)
15
Q
The superior laryngeal nerve divides into what two nerves?
A
- Internal superior laryngeal nerve
- External superior laryngeal nerve
16
Q
Internal SLN
A
- Provides sensation to supraglottic and ventricle compartment
- Stimulation causes laryngospasm!
17
Q
Stimulation of internal SLN causes ___
A
LARYNGOSPASM
18
Q
External SLN provides ___ innervation to what muscle?
A
Motor innervation to cricothyroid muscle
19
Q
Recurrent laryngeal nerve is a branch of what cranial nerve?
A
Vagus nerve (CN X)
20
Q
Left RLN passes @ ___
A
Aortic arch
21
Q
Recurrent laryngeal nerve provides sensory innervation to ___
A
Infraglottis
22
Q
Recurrent laryngeal nerve provides motor innervation to all of the larynx except for the ___ muscle
A
Cricothyroid muscle
23
Q
Stimulation of the recurrent laryngeal nerve causes ___
A
Abduction of vocal cords
24
Q
Damage to the recurrent laryngeal nerve causes ___
A
Vocal cord adduction
25
What is the trachea?
Flexible cylindrical tube supported by 20-25 C-shaped cartilages
26
Diameter of the trachea
18-20 mm diameter
27
Length of trachea
12.5-18 cm length
28
Trachea extends from ___ to ___
C6 to T5
29
Where does the trachea divide into 2 bronchi?
At carina (level T5-T7); 25 cm from teeth
30
Inspiration is the ___ phase of breathing cycle
Active phase
31
What nerve transmits motor stimulation to diaphragm?
Phrenic nerve—C3, C4, C5
32
What nerves send signals to the external intercostal muscles?
Intercostal nerves (T1-T11)
33
The act of inhaling is ___
Negative-pressure ventilation
34
Transpulmonary pressure is the pressure difference between ___ and ___
Alveolar pressure and pleural pressure on outside of lungs
Alveoli tend to collapse together while the pleural pressure attempts to pull outward
35
What is recoil pressure?
The elastic forces which tend to collapse the lung during respiration
36
4 volumes of spirometry
- Tidal volume (TV)
- Inspiratory reserve volume (IRV)
- Expiratory reserve volume (ERV)
- Residual volume (RV)
37
Tidal volume (TV)
Amount of inspired air with a normal breath; amounts to about 500 ml in the avg adult male
38
Inspiratory reserve volume (IRV)
Extra volume of air that can be inspired over and above the normal tidal volume when the person inspires with full force; usually equals 3000 ml
39
Expiratory reserve volume (ERV)
Maximum extra volume of air that can be expired by forceful expiration after the end of a normal tidal expiration; about 1100 ml
40
Residual volume (RV)
Volume of air remaining in the lungs after the most forceful expiration; about 1200 ml
41
4 capacities of spirometry
- Inspiratory capacity (IC)
- Functional residual capacity (FRC)
- Vital capacity (VC)
- Total lung capacity (TLC)
42
Inspiratory capacity (IC) =
TV + IRV
The amount of air a person can breathe in, beginning at the normal expiratory level and distending the lungs to the maximum amount ~3500 ml
43
Functional residual capacity (FRC) =
ERV + RV
The amount of air that remains in the lungs at the end of normal expiration ~2300 ml
44
Vital capacity (VC) =
TV + IRV + ERV
The maximum amount of air a person can expel from the lungs after first filling the lungs to their maximum extent and then expiring to the maximum extent ~4600 ml
45
Total lung capacity (TLC) =
VC + RV
TV + IRV + ERV + RV
Max volume to which the lungs can be expanded with the greatest possible effort ~5800 ml
46
IC =
IRV + TV
47
FRC =
ERV + RV
48
VC =
IRV + ERV + TV
49
TLC =
IRV + TV + ERV + RV
50
TV ~
~500 ml
51
IRV ~
~3000 ml
52
ERV ~
~1100 ml
53
RV ~
~1200 ml
54
IC ~
~3500 ml
55
FRC ~
~2300 ml
56
VC ~
~4600 ml
57
TLC ~
~5800 ml
58
Spirometry cannot measure ___
Residual volume (RV)
Thus FRC and TLC cannot be determined using spirometry alone
59
FRC and TLC can be determined by ___, ___, and ___
- Helium dilution
- Nitrogen washout
- Body plethysmography
60
What are 3 main functions of surfactant?
- Lowers surface tension of alveoli and lung—increases compliance of lung; reduces work of breathing
- Promotes stability of alveoli—alveoli have tendency to collapse; surfactant reduces forces causing atelectasis
- Prevents transudation of fluid into alveoli—reduces surface hydrostatic pressure effects; prevents surface tension forces from drawing fluid into alveoli from capillary
61
What type of cells secrete surfactant?
Type II pneumocyte
Very important in neonates—maturation occurs at 24 weeks gestation
62
What forces air out of alveoli?
Elastic force caused by water tension attempts to force air out of alveoli
63
Poiseuille’s Law—reducing the radius by 16% will ___ the resistance
Double
64
Poiseuille’s Law—reducing the radius by 50% will increase resistance ___
16-fold (2^4)
65
If you double the radius, you reduce the resistance ___
16-fold (2^4)
66
Systemic circulation = ___ pressure, ___ flow, ___ resistance
High pressure, low flow, high resistance
67
Pulmonary circulation = ___ pressure, ___ flow, ___ resistance
Low pressure, high flow, low resistance
68
RA pressure
2-3 mm Hg
69
RV pressure
25 mm Hg
70
LA pressure
5-8 mm Hg
71
LV pressure
120 mm Hg
72
Mean pulmonary artery pressure
14-15 mm Hg
73
Mean systemic artery pressure
90-100 mm Hg (120/80)
74
Mean pulmonary capillary pressure
10-10.5 mm Hg
75
Mean systemic capillary pressure
20 mm Hg
76
What is recruitment?
Opening of previously closed vessels
77
What is distention?
Increase in caliber of vessels
78
What is the CHIEF mechanism for fall in pulmonary vascular resistance (PVR)?
Recruitment
However, both recruitment and distention are two mechanisms that decrease PVR
79
Increased CO ___ pulmonary vascular pressures but ___ pulmonary vascular resistance
Increases pulmonary vascular pressures but decreases pulmonary vascular resistance (occurs during periods of stress and increased tissue oxygen demand)
80
___% of alveolar surface area is covered by capillary bed
70-80%
Total capillary surface area almost equals alveolar surface area
81
Capillary volume increases by ___
Recruitment—opening closed segments
82
What is the normal capillary volume at rest?
70 ml (1 ml/kg body weight)
83
What is the maximal capillary anatomical volume?
200 ml
84
Distance RBCs have to travel through capillary network is ___
Small (600 to 800 micrometers)
85
Capillary network blood volume = ___ stroke volume
RV
86
Total blood volume from main pulmonary artery to left atrium is ___ ccs
500
87
Lung is ___% blood by weight
40-50%; this volume fraction > than any other organ
88
What is the capacitance reservoir for the left atrium?
The pulmonary vasculature—can act as a reservoir and alter its volume from 50 to 200% of resting volume
Can store blood in the lungs so that the LV doesn’t run dry as it pumps out to the systemic circulation
89
Inspired air O2/CO2 concentrations
PO2 150 mm Hg
| PCO2 0 mm Hg
90
RBC/alveolar O2/CO2 concentrations
```
PO2 = 100 mm Hg
PCO2 = 40 mm Hg
```
91
Deoxygenated blood O2/CO2 concentrations
```
PO2 = 40 mm Hg
PCO2 = 46 mm Hg
```
92
Lung Zone 1
alveolar flow > pulmonary artery pressure > pulmonary vein pressure
very negligible blood flow through this area of the lung; can ventilate it all day long, but it’s not doing any gas exchange
93
Lung Zone 2
pulmonary artery pressure > alveolar pressure > pulmonary vein pressure
might get intermittent flow/exchange through zone 2 with changes in systolic/diastolic pressure during inhalation/exhalation; not a lot of flow/exchange going on here
94
Lung Zone 3
pulmonary artery pressure > pulmonary vein pressure > alveolar pressure
maximizes both blood flow and gas exchange because you have uninterrupted alveolar interfaces
95
Blood vessels are more distended at the ___ of the lung
Base
96
___ resistance to flow in the base of the lung
Decreased
97
___ (higher/lower) blood flow at the base of the lung
Higher
98
Higher ___ pressures in apex of lung than capillary pressures
Higher alveolar pressures; causes decreased perfusion in apex of lung
99
What are 3 ways to expand zone 1?
- Decreased pulmonary artery pressure (i.e.: shock, hypovolemia)
- Increased alveolar pressure (i.e.: PEEP)
- Occlusion of blood vessels (i.e.: pulmonary embolism)
100
What are 2 ways to reduce zone 1?
- Increased pulmonary artery pressure (i.e.: infusion of fluid or blood)
- Reduced hydrostatic effect (i.e.: change patient position; standing to supine)
101
V/Q ratio is ___ in the upper lung
High
Because you have ventilation, but no perfusion
102
V/Q ratio is ___ in the lower lung
Low
Because you have good ventilation & perfusion in the bases of the lungs
103
What are 4 things that cause vasoconstriction of the pulmonary vasculature?
- Reduced PaO2
- Increased PCO2
- Thromboxane A2
- Histamine
104
What are 3 things that cause vasodilation of the pulmonary vasculature?
- Increased PaO2
- Prostacyclin
- Nitric oxide
105
High CO2 =
Vasoconstriction
Why we hyperventilate neurosurgery patients...because low CO2 = vasodilation
106
Thromboxane A2 is a ___
Potent vasoconstrictor
107
Thromboxane A2 is produced during...
Produced during acute lung tissue damage by
macrophage, leukocytes, and endothelial cells
Effect localized to injured region because half-time of thromboxane inactivation is only seconds
Body’s way of protecting itself when the lung is injured
108
Prostacyclin is a ___
Potent vasodilator
109
Prostacyclin inhibits ___
Platelet activation
110
Nitric oxide is a ___
Epithelial vasodilator
111
Nitric oxide has a ___ effect
Strictly localized effect (only works where it is produced)
112
Nitric oxide is produced from ___
L-arginine
113
How does nitric oxide cause vasodilation?
Nitric oxide activates guanylyl cyclase, which produces cyclic GMP...cyclic GMP causes smooth muscle relaxation
114
Nitric oxide is delivered via ___
Inhalation technique
115
Nitric oxide is very ___ at high concentrations
Toxic
116
Nitric oxide binds ___ to hemoglobin
Irreversibly
117
Nitric oxide binds to hemoglobin ___ x’s greater than oxygen
200,000x’s greater
118
Alveolar hypoxia produces ___
Hypoxic pulmonary vasoconstriction (HPV)
119
HPV is a ___ response
Localized response of pulmonary arterioles
120
HPV is caused by ___ and enhanced by ___ and ____
Hypoxia; enhanced by hypercapnia and acidosis
121
HPV is a mechanism of balancing ___ ratio
V/Q
122
HPV causes a shift of flow to ___
Better ventilated pulmonary regions
123
Normal alveolar PO2 is ___
100 mm Hg
124
Normal alveolar PCO2 is ___
40 mm Hg
125
Alveolar PCO2 ___ in proportion to CO2 excretion
Increases
126
As alveolar ventilation increases, PCO2 ___
Decreases (inverse relationship; O2 has direct relationship with alveolar ventilation)
127
Normal CO2 production at rest is ___
200 ml/min
128
Expired air is a combination of ___ air and ___ air
Dead space air and alveolar air
First portion of expired air = dead space air; consists of humidified air
Second portion of expired air = mixture of both dead space and alveolar air
129
Alveolar air is expired at the end of ___
Exhalation
130
What 4 factors affect diffusion? (according to Fick’s Law)
- Cross sectional area of membrane
- Partial pressure differences
- Gas coefficient
- Tissue thickness
Increase in:
-Cross sectional area
-Partial pressure difference (concentration gradient)
-Gas coefficient
INCREASE rate of diffusion; all are directly related to rate of diffusion
Tissue thickness is inversely related to rate of diffusion (thicker tissue = slower rate of diffusion)
131
V/Q is normal when...
Alveolar ventilation and blood flow are both normal
132
V/Q = zero
Ventilation = zero but perfusion is present (i.e.: complete airway obstruction)
133
V/Q = infinity
If ventilation is present but there is no perfusion (i.e.: pulmonary artery obstruction)
134
If V/Q ratio is zero or infinity, there is ___
No exchange of gases
135
Physiologic shunt—V/Q is ___
Below normal
136
Shunt =
Perfusion but no ventilation...blood is being shunted from pulmonary artery to pulmonary vein without participating in gas exchange
137
Shunted blood is not ___
Oxygenated
138
The greater the physiologic shunt, the greater the...
Amount of blood that fails to be oxygenated in the lungs
139
Physiologic dead space—V/Q is ___
Greater than normal
140
Dead space =
Ventilation but no perfusion...more available oxygen in alveoli than can be transported away by flowing blood
141
Physiologic dead space includes ___ and ___
- Wasted ventilation
| - Anatomical dead space
142
When physiologic dead space is great, much of the work of breathing is wasted effort because ___
Ventilated air does not reach blood
143
SaO2 100%, PaO2 ___
100+
144
SaO2 95%, PaO2 ___
75
145
SaO2 90%, PaO2 ___
60
146
SaO2 75%, PaO2 ___
40 (mixed venous blood in pulmonary artery)
147
SaO2 60%, PaO2 ___
30
148
SaO2 50%, PaO2 ___
27
149
Very rough rule—PaO2 40, 50, 60 for sat ___, ___, ___
70, 80, 90
150
Hemoglobin-oxygen equilibrium curve is affected in two ways:
- Shift in position (left or right)
| - Change in shape
151
What indicates a greater interference with O2 transport—a change in position or shape?
Change in shape
152
Change in shape of the HbO2 equilibrium curve is d/t change in ___
Hemoglobin
153
Right shift of Hb-O2 dissociation curve—Hb has ___ affinity for O2, ___ O2, saturation will be ___ for a given PO2
Hb has less affinity for O2, releases O2, saturation will be less for a given PO2
154
Left shift of Hb-O2 dissociation curve—Hb has ___ affinity for O2, ___ O2, saturation will be ___ for a given PO2
Hb has higher affinity for O2, binds O2, saturation will be higher for a given PO2
155
4 causes of right shift:
- Increased CO2
- Increased temp
- Decreased pH/increased H+
- Increased 2,3 DPG
156
3 causes of left shift:
- Increased pH
- Decreased temp
- Decreased 2,3 DPG
157
What is the Bohr effect?
Shift to the right d/t increase H+
158
What has the greatest effect on the Hb-O2 dissociation curve?
A change in shape (so a change in hemoglobin) has the greatest effect on the curve than does any shift change (right or left)
159
CaO2 =
O2 content in the blood...the sum of O2 carried on Hb and dissolved in plasma
160
Formula for CaO2 =
(SaO2 x Hb x 1.31) + (PO2 x 0.003)
161
1.31 =
ML of oxygen bound to one gram of hemoglobin
162
0.003 =
O2 dissolved in 100 ml plasma...very small amount of oxygen dissolved in plasma
163
Most CO2 is transported as ___
Bicarbonate (HCO3-)
164
DRG or VRG controls respiration?
DRG
165
What two cranial nerves deliver sensory information to the DRG?
- Glossopharyngeal (CN IX)
| - Vagus (CN X)
166
DRG receives signals from what 3 sources?
- Peripheral chemoreceptors
- Baroreceptors
- Lung receptors
167
VRG is ___ during normal respiration
Inactive; only becomes active during exercise
168
What is the chemosensitive area of the brainstem?
Highly sensitive area on ventral medulla surface; contains central chemoreceptors
169
Chemosensitive area of brainstem is responsive to changes in ___ or ___
Blood PCO2 or H+ ion concentration
170
Effect of CO2 on respiratory center activity
Increased CO2 = increased respiratory center activity
171
CO2 has potent direct effect via ___ on the chemosensitive area
H+
172
CO2 is highly permeable to blood-brain barrier, so blood and brain concentrations are ___
Equal
173
How does CO2 form H+ ions?
CO2 + water —> carbonic acid, dissociates into H+ and bicarbonate ions in medulla/CSF
Released H+ ions in brain stimulate respiratory center activity
174
CO2 diffuses ___ faster than oxygen does
20x’s faster
175
What has greater effect on alveolar ventilation—change in PCO2 or change in pH?
PCO2
176
Ventilation is greatly increased with blood PCO2 above ___
35 mm Hg—steep part of curve
177
Chemoreceptors are located in ___ and ___
Carotid and aorta
178
Peripheral chemoreceptors are stimulated by ___
Hypoxemia
179
Where are the carotid bodies located?
Bifurcations in common carotid
180
Carotid bodies innervation to DRG
CN IX (glossopharyngeal)
181
Where are the aortic bodies located?
Aortic arch
182
Aortic bodies innervation to DRG
CN X (vagus)
183
Central chemoreceptors are located in the ___
Chemosensitive area of brainstem
184
Peripheral chemoreceptors are located in ___ and ___
Carotid and aortic bodies
185
Stimulation of chemoreceptors is caused by ___
Decreased arterial oxygen content
186
Ventilation doubles when PaO2 falls below ___
60 mm Hg
187
High risk PFT results—FEV1 < ___
FEV1 < 2L
188
High risk PFT results—FEV1/FVC < ___
FEV1/FVC < 0.5
189
High risk PFT results—VC < ___ in adult; VC < ___ in child
VC < 15 cc/kg in adult; VC < 10 cc/kg in child
190
High risk PFT results—VC < ___
40 to 50% of predicted
191
Intubation criteria—mechanics: RR > ___, VC < ___, NIF ___
RR > 35
VC < 15 cc/kg adult or < 10 cc/kg child
NIF less negative than -20 cm H2O
192
Intubation criteria—PaO2 < ___ on FiO2 40%
PaO2 < 70 mm Hg on FiO2 40%
193
Intubation criteria—PaCO2 > ___
PaCO2 > 55 (except in chronic hypercarbia)
194
Intubation criteria—Vd/Vt > ___
Vd/Vt > 0.6 (remember, normal dead space is 30%)
195
Intubation criteria—clinical status (6)
- Airway burn
- Chemical burn
- Epiglottitis
- Mental status change
- Rapidly deteriorating pulmonary status
- Fatigue
196
Increase of PCO2 by 10 mm Hg causes a decrease in pH by ___
0.08
Likewise, a decrease of PCO2 by 10 mm Hg will increase pH by 0.08
So an acute increase in CO2 to 60 should cause a drop in pH to 7.24 (consider normal PCO2 is 40)
197
Hypoxemia =
Decrease PO2 in blood, < 75
198
Hypoxia =
A low O2 state
199
A-a gradient is a measure of ___
Efficiency of lung
200
How to calculate PaO2 (formula)
PaO2 = (PB - PH2O) x (FiO2) - (PaCO2/0.8)
```
PB = atmospheric pressure, 760 mm Hg
PH2O = vapor pressure, 47 mm Hg
```
201
Normal A-a is approximately ___
Age/3
202
A-a gradient is ___ during anesthesia and with intrinsic lung disease (i.e.: PTX, PE, shunt, V/Q mismatch, diffusion problems)
Widened
203
A-a gradient is normal with ___ or ___
Hypoventilation or low FiO2
204
Treatment of hypoxemia/hypoxia
TREAT UNDERLYING CAUSE!!!
205
A decrease in bicarbonate by 10 mmoles decreases pH by ___
0.15
An increase in bicarbonate by 10 mmoles increases pH by 0.15
A bicarbonate of 13 would result in a pH of 7.25 (consider normal bicarbonate is 23)
206
Total body bicarbonate deficit =
Base deficit x weight in kg x 0.4; in meq/L
Usually replace 1/2 bicarbonate deficit
207
Pulse ox is a ___ intraoperative monitor
Mandatory
208
940 nm =
Infrared light, oxyhemoglobin
209
660 nm =
Red light, deoxyhemoglobin
210
What 2 hemoglobin variants affect pulse oximetry?
Carboxyhemoglobin (COHb)
| Methemoglobin (MetHb)
211
Carboxyhemoglobin shows a SPO2 of ___
100%—overestimation of true oxygenation
212
What is used to distinguish between CO and oxygen levels?
Co-oximetry
213
Cyanosis is seen in methemoglobinemia when ___ of Hb is in methemoglobin form
15%
214
Methemoglobin shows a SPO2 of ___
85%
215
Treatment of methemoglobinemia
Methylene blue or ascorbic acid
216
What two things do NOT affect pulse oximetry?
Fetal hemoglobin and bilirubin
217
Capnography indicates ___ but does not reliably detect ___
Esophageal intubation; endobronchial intubation
218
What is the gold standard for tracheal intubation?
+ ETCO2
219
Capnometer
Measures CO2
220
Capnograph
Records and displays CO2
221
CO2 are depicted graphically as a ___
Capnogram
222
CO2 is recorded by a ___
Capnograph
223
CO2 is measured by a ___
Capnometer
224
What point on the capnograph is the recorded ETCO2?
D point
225
In the awake and lateral position, the ___ lung is better perfused and ventilated
Dependent
226
Under anesthesia with a decrease in FRC, the ___ lung ventilates more
Upper lung; creates a V/Q mismatch
227
What are 6 factors that inhibit hypoxic pulmonary vasoconstriction?
- Very high or very low PA pressures
- Hypocapnia
- High or very low mixed venous PO2
- Vasodilators—NTG, Nitroprusside (SNP), beta-adrenergic agonists (dobutamine), calcium channel blockers
- Pulmonary infections
- Inhalation agents
228
How does Hypocapnia affect HPV?
Inhibits HPV
229
How do vasodilators like NTG and Nitroprusside (SNP) affect HPV?
Inhibit HPV
230
How do inhalation agents affect HPV?
Inhibit HPV
231
What do you want to set the FiO2 for one lung ventilation?
80-100%
232
Tidal volumes for one lung ventilation
10cc/kg
233
What do you use to ensure proper ETT placement during one lung ventilation?
Fiber optic scope
234
Where do you want to keep PaCO2 during one lung ventilation?
Keep PaCO2 at 40 mm Hg
235
Add 5 cm H2O CPAP to ___ lung
Nondependent (upper) lung—warn surgeon
236
Add 5 cm H2O PEEP to ___ lung
Dependent lung—treats atelectasis but may increase vascular resistance
237
Increase both CPAP and PEEP ___ during one lung ventilation
Slowly
238
During apnea, PCO2 increases ___ mm Hg for the first minute and then ___ mm Hg for each additional minute of apnea
5 mm Hg for first minute; 3 mm Hg for each additional minute
Example: if PCO2 was 40, then after 10 minutes of apnea, the PCO2 will be 72.
239
Progressive respiratory acidosis limits hypoxia during one lung ventilation to ___ minutes
10-20 minutes
240
First most sensitive sign of MH =
Unexplained tachycardia
241
Most specific sign of MH =
Increasing ETCO2–hypercapnia 2-3x normal
242
Initial ABG for MH
Initial metabolic acidosis, then a combined metabolic and respiratory acidosis
243
Dantrolene dosage for MH
2.5 mg/kg every 5 minutes
244
Max dose of dantrolene for MH
10 mg/kg
245
After MH has subsided, continue to give how much dantrolene?
1 mg/kg every 6 hours for 72 hours
246
What should not be given to the MH patient while on dantrolene?
Calcium channel blockers—can cause life-threatening hyperkalemia/myocardial depression
247
Persistent ventricular arrhythmias during MH should be treated with ___
Procainamide...NOT calcium channel blockers
248
How does dantrolene work?
Muscle relaxant that works directly on the ryanodine receptor to prevent the release of calcium—it inhibits Ca release from the sarcoplasmic reticulum
249
What drugs cause MH?
All inhalation agents (except nitrous) and succs (depolarizing muscle relaxant)
250
Does propofol cause MH?
No!
251
Do non-depolarizing muscle relaxants cause MH?
No! Depolarizing muscle relaxant SUCCS does cause MH
252
What is the gold standard pre-op test for MH?
Muscle biopsy with halothane-caffeine contracture test—78% specific, 97% sensitive
Caffeine causes muscle to contract
Halothane in the MH patient causes more forceful contraction
253
Does a prior uneventful general anesthetic rule out the possibility of MH?
NO!
254
Who has the highest MAC requirement?
Term infant to 6 months of age
255
Hyperthermia ___ MAC
Increases
256
Chronic EtOH abuse ___ MAC
Increases
257
Hypernatremia ___ MAC
Increases
258
Drugs that increase CNS catecholamines ___ MAC
Increase
259
Pregnancy ___ MAC
DECREASES
260
Hypothermia ___ MAC
Decreases
For every 1 deg C drop in body temp, MAC decreases 2 to 5%
261
Acute EtOH ingestion ___ MAC
Decreases
262
What are 5 factors that have NO EFFECT on MAC?
- Thyroid gland dysfunction
- Duration of anesthesia
- Gender
- Hyper/hypokalemia
- Hyper/hypocarbia
263
What is the second gas effect?
Large volume uptake of a first gas (nitrous) accelerates the delivery of a second gas, thus speeding induction
264
What is diffusion hypoxia?
Large amount of nitrous dilutes alveolar O2 concentration, causing hypoxia
265
High risk pts for diffusion hypoxia?
Patients with a concurrently decreased FRC:
- Pregnancy
- Obesity
- Children
266
How can you avoid diffusion hypoxia?
Administer 100% O2 following N2O use
267
Nicotine from smoking stimulates ___
Sympathetic ganglia—catecholamine release
268
Nicotine causes catecholamines to be released from ___
Adrenal medulla
Increase HR, BP, and SVR
269
Sympathetic stimulation from nicotine persists ___ after last cigarette
30 minutes
270
How does smoking irritate the airway?
- Increased mucus production
- Decreased ciliary clearance
- Increased inflammation
- Reduced surfactant
271
What should you, the anesthesia provider, do when prepping a case for a smoker?
Pre-oxygenate well and avoid instrumentation of airway until deep level of anesthesia is achieved
272
Advise smokers to stop smoking at least ___ prior to surgery
12 hours
273
If patient stops smoking night before surgery (12-24 hours), COHb and nicotine levels will be reduced to that of ___
Non-smokers
274
Airway reactivity decreases after ___ days of cessation
2 days
275
Airway reactivity is near the level of a non smoker after ___ days of cessation
10 days
276
Cessation of > 8 weeks will reduce ___
Post-op pulmonary complications
277
Cessation of > 2 years will reduce risk of ___
MI to that of nonsmoking population
278
Severe emphysema requires longer ___
Expiratory times
Normal I:E is 1:2, so in COPD —> 1:3
279
Closely monitor ___ to avoid rupturing an emphysematous blob or bullae, PTX
Peak inspiratory pressures (PIP)
280
CO2 retainers—ETCO2 should be kept near ___; a rapid correction will lead to ___
The patient’s baseline; metabolic alkalosis
281
Caution using ___(what inhalation gas) in COPD patients; may expand bullae and worsens pulmonary HTN
Nitrous oxide
282
What 2 inhalation agents could cause airway stimulation and should not be used in COPD patients?
- Desflurane
| - Isoflurane
283
What is worsened after inhalation agents?
Mucociliary clearance—results in lots of secretions...suction ETT frequently
284
Avoid ___ to prevent bronchospasm in COPD patients
Histamine releasing drugs—Pentothal (STP), morphine, atracurium, mivacurium, neostigmine
285
Treat patient with ___ to minimize chance of bronchospasm, especially before extubation
Nebulized albuterol
