ITE Chiefs Review Flashcards
1
Q
What does P wave represent?
A
electrical activation of atria; precedes atrial contraction
2
Q
Atrial systole contributes to __% of filling of ventricle
A
25%
3
Q
What does QRS represent?
A
electrical activation of ventricles
4
Q
What does T wave represent?
A
ventricular repolarization; marks end of ventricular contraction/rapid ejection
5
Q
What action begins after QRS wave?
A
isovolumetric contraction
6
Q
What is normal LVEDV?
A
120 mL
7
Q
What is the average stroke volume?
A
80 mL
8
Q
What are the three parts of systole?
A
- isovolumic contraction
- rapid ejection (2/3 LVEDV)
- slower ejection
9
Q
What are the four parts of diastole?
A
- isovolumic relaxation
- early filling (70-75%)
- diastasis (<5%)
- atrial systole (15-20%)
10
Q
____ = amt of blood per minute
A
cardiac output
11
Q
What four things affect cardiac output?
A
- preload (LVEDV)
- afterload (aortic pressure/BP)
- myocardial contractility (inotropy)
- HR (chronotropy)
12
Q
The primary determinant of myocardial O2 consumption is ___.
A
HR
13
Q
Formula for CO
A
CO = HR x SV
14
Q
Formula for Ohm’s law
A
Q (output) = pressure/resistance
15
Q
An increase in ___ is most likely to result in increased myocardial wall tension
A
ventricular cavity size
16
Q
What causes LVH?
A
chronic HTN (increased pressure load on LV) causes hypertrophy => decreased wall tension
17
Q
Formula for LaPlace’s law
A
T = Pr/2h
- T(ension)
- P(ressure)
- r(adius) of chamber
- h = wall thickness
18
Q
Why do you diurese/venodilate CHF?
A
reduces preload => decreased radius, decreased wall tension, less myocardial O2 consumption
19
Q
What happens to heart with decompensated HFrEF?
A
increased r and thin myocardium (decreased h) => increased wall tension
20
Q
How is parasympathetic innervation of heart accomplished?
A
craniosacral: long preganglionic fibers with short postganglionic fibers in heart
21
Q
Function of parasympathetic innervation of heart?
A
- slows HR
- reduces conduction velocity
22
Q
What is the primary neurotransmitter for parasympathetics?
A
ACh
23
Q
What neurotransmitters are involved in sympathetic innervation of heart?
A
- ACh (stellate gang synapse)
2. NE (postganglionic)
24
Q
How is heart innervated sympathetically?
A
thoracolumbar; synapse in stellate ganglion
25
Through what receptors in the heart does sympathetic innervation work?
beta-1: increases rate and conduction cells
26
What is the Bezold Jarisch reflex?
incr ventricular volume => vagal => decreased HR and MAP
27
Effects of sympathetic stimulation in heart?
1. chronotropic
2. dromotropic incr conduction velocity)
3. inotropic
4. lusitropic (incr rate of myofibrillar relaxation)
28
____ = systemic HTN in response to increased ICP
Cushing reflex
attempt to maintain cerebral perfusion/O2 delivery
29
What is the occulocardiac reflex?
pressure on ocular globe => brady, hypoT
30
What are the two types of sensitive receptors involved in heart innervation?
1. baroRs (arterial; depends on arterial BP)
| 2. chemoRs (periph; senses incr PaCO2, decr in pH)
31
During off pump CABG, a clamp is placed on a coronary artery. New onset junctional rhythm is seen on the EKG monitor and new inferior wall motion abnormalities are seen on TEE. What coro is affected?
RCA
32
What makes up the L main?
L main = LAD + L circumflex
33
What part of heart does the right main cover?
- ant/post RV wall
- RA
- SA node
- upper half of atrial septum
- post 1/3 interventricular septum
- inferior LV wall
- AV node
- post base LV
34
What circulation supplies the SA node and the AV node?
R main
35
What does the LAD supply?
- anterior LV wall
| - anterior 2/3 of interventricular septum
36
What does the L circumflex supply?
- lateral LV wall
| - part of LV posterior wall
37
Wall abnormality associated with RCA
RCA = inferior wall
38
Wall abnormality associated with LAD
LAD = anterior wall
39
Wall abnormality associated with circumflex
circumflex = lateral wall
40
Formula for coronary perfusion
coronary perfusion = aortic pressure (DBP) - LVEDP
41
What is resting coronary blood flow, and how much of cardiac output does it make up?
250 mL/min
5% of CO
42
What layer of heart tissue is most at risk for ischemia?
subendocardium
43
What does the Frank-Starling curve describe?
contractile state of myocardium
44
What three things are inotropic?
1. catecholamines
2. digitalis
3. sympathetic stimulation
45
What two things are negative inotropes?
1. pharm depressants
| 2. loss of myocardium
46
In what 4 cases is PAOP > LVEDP?
PAOP > LVEDP:
1. mitral stenosis
2. L atrial myxoma
3. pulm venous obstruction
4. elevated alveolar pressure
47
In what 3 cases is PAOP < LVEDP?
PAOP < LVEDP:
1. aortic regurg
2. stiff LV
3. LVEDP > 25 mmHg
48
25 yo man with known rheumatic heart disease is being evaluated in the ICU. Despite decreasing C.O., mixed venous blood from a PAC shows an increase in SvO2. Why?
wedging of catheter
49
The acute onset of hypotension without a decrease in mixed venous oxygen saturation in most likely associated with the onset of ____.
sepsis
50
In a patient with hypovolemic shock, what factor is the best measure of the overall balance between oxygen supply and demand?
mixed venous O2 sat
51
Formula for SvO2
SvO2 = SaO2 - (vO2/1.3 x CO x Hg)
52
What is a normal mixed venous O2 sat?
70%; 40 mmHg
53
With what tool must you measure mixed venous O2 sat?
PAC
54
With what tool must you measure mixed venous O2 sat?
PAC
55
What are the two broad reasons for decreased SvO2?
1. incr O2 consumption
| 2. decr O2 delivery
56
What are the four things that decrease SvO2 by increasing O2 consumption?
1. fever
2. shivering
3. MH
4. thyroid storm
57
What are the four things that decrease SvO2 by decreasing O2 delivery?
1. hypoxia
2. decreased CO
3. decreased Hgb (hemorrhage)
4. abnormal Hgb
58
Effect on SvO2:
| fever
decreased SvO2
59
Effect on SvO2:
| shivering
decreased SvO2
60
Effect on SvO2:
| MH
decreased SvO2
61
Effect on SvO2:
| thyroid storm
decreased SvO2
62
Effect on SvO2:
| hypoxia
decreased SvO2
63
Effect on SvO2:
| decreased CO
decreased SvO2
64
Effect on SvO2:
| decreased Hgb
decreased SvO2
65
Effect on SvO2:
| abnormal Hgb
decreased SvO2
66
Effect on SvO2:
| L=>R shunting
increased SvO2
67
Effect on SvO2:
| high CO
increased SvO2
68
Effect on SvO2:
| cyanide
increased SvO2
69
Effect on SvO2:
| hypothermia
increased SvO2
70
Effect on SvO2:
| sepsis
increased SvO2
71
Effect on SvO2:
| wedged PA
increased SvO2
72
What are some broad reasons for increased SvO2?
- L=>R shunt
- high CO
- impaired tissue uptake
- decr O2 consumption
- sepsis
- sampling error
73
Thermodilution is used to measure ___.
CO
74
What two issues invalidate thermodilution?
| Why?
1. tricuspid regurg
2. cardiac shunts
only RV output is measured
75
How does thermodilution work?
1. known amt of fluid injected in proximal port of PAC (into RA)
2. temp measured at tip of PAC (in pulm a.)
3. temp change is inversly proportional to CO
76
What three things cause falsely high CO by thermodilution?
1. too little injectate
2. TR
3. cardiac shunts
77
Which of these are contraindicated in pulm HTN?
a) 15-methylprostaglandin F2alpha
b) sildenafil
c) nitric oxide
d) epoprostenol
15-methylprostaglandin F2alpha
78
MC sx associated with pulm HTN?
- incr SOB with activity
- CP at low exertion
- fatigue
- lethargy
- fainting
- leg swelling
79
What is the definition of pulm HTN?
mean PAP > 25 mmHg at rest
80
What are the 5 classifications of pulm HTN?
1. PAH
2. 2/2 L-sided heart dz
3. 2/2 lung dz/hypoxia
4. chronic thomboembolic pulm HTN
5. unclear/multifactorial
81
What are some predictors of poor outcome with surg/anesth?
- poor exercise capacity (6-min walk)
- elevated RA pressure
- decreased RV fxn/failure
- low CI
- elevated BNP
- elevated CRP
82
Moderate/severe pulm HTN is a contraindication for ____.
liver transplant
83
What are some goals for anesthetizing people with pulm HTN?
- prevent hypoT
- tx hypoT with phenylephrine, vasopressin, NE
- maintain adequate preload/contractility
- prevent hypoxia, hypercapnia, acidosis
84
Three classes of tx for pulm HTN?
1. prostacyclins (epoprostenol infusion, iloprost inhaled)
2. PDE inhibitors (sildenafil, tadalafil, milrinone)
3. consider inhaled NO
85
What is protamine?
only compound that reverses heparin
basic compound that binds acidic residues of heparin
86
What happens in a protamine reaction?
pulm HTN:
- heart pressure equalize = tamponade
- CO decr, PVR decr, SVR incr
87
What causes protamine reaction
increased plasma thromboxane
88
How do you treat a protamine reaction?
can do:
- epi
- heparin/bypass
89
What are the four components of the pathophysiology of protamine reaction?
1. coagulopathy
2. histamine release
3. IgE-mediated (type II): d/t prev sensitization (NPH, fish allergy, vasectomy)
4. anaphylactoid rxn (type III): complement/IgG; TXA2 release => severe pulm vasoconstriction, pulm HTN, possible R heart failure
90
A 77 yo woman with a biventricular implantable cardioverter-defibrilator (ICD) device is scheduled for an elective thyroidectomy. Interrogation of her device 2 days ago revealed 99.9% of beats were paced in DDD mode at 60 bpm. Per report, there is no underlying (intrinsic) cardiac rhythm. How do you prevent pacemaker inhibition by surgical electrocautery?
reprogramming pacer to asynchronous mode
91
Name four ways to inhibit/inactivate programmable DVI pacemaker.
1. myopotentials from shivering
2. succ-induced fasciculations
3. ventricular R wave
4. magnet over it
92
T or F: AICDs are not affected by ECT.
true
93
Name four things that affect AICDs.
1. MRI
2. radiation
3. unipolar cautery
4. radiofreq ablation
94
Given the complete general defibrillator code of VVE-DDDRV, what is true about this ICD?
provides ventricular chamber antitachycardia pacing
95
What are the five parts of pacer codes, and what are the options for these?
1st = chamber paced
-0 (none), A, V, D (dual)
2nd = chamber sensed
-0, A, V, D
3rd = response
-0, T (triggered), I (inhibited), D
4th = programmability/rate modulation
-0, P, M, C, R
5th = antitachy fxn
-0, P, S, D
96
What are the four parts of ICD codes, and what are the options for these?
1st = shock chambers
-0, A, V, D
2nd = antitachy pacing chambers
-0, A, V, D
3rd = tachy detection
-E (electrogram), H (hemodynamic)
4th = antibrady pacing chambers
-0, A, V, D
97
What are the parts of the CPB machine?
- reservoir = grav-dependent; accumulates deoxy blood from venous circ
- heat exchange (uses water countercurrents)
- oxygenator (membrane or bubble)
- filter system
then returned to ascending aorta
98
What are the two types of CPB pumps?
1. centrifugal pumps
| 2. roller pumps
99
What are the cons of CPB centrifugal pumps?
potential for retrograde flow and exsanguination
100
What are the cons of CPB roller pumps?
- incr trauma to RBCs
| - can pump massive amts of air into circuit
101
How do CPB centrifugal pumps work?
- nonpulsatile flow
- non occlusive (less RBC trauma)
- afterload dependent (no line rupture)
- no air can be pumped (less dense than blood)
102
How do CPB roller pumps work?
- occlude blood tubing and move forward
| - generates high pos/neg pressures
103
In what type of cases is microultrafiltration used?
peds hearts
104
What are the benefits of microultrafiltration
- decr total body water
- blunts anemia/coagulopathy
- decr blood requirements
- narrows A-a gradient
- improved LV compliance/systolic fxn
- decr inotropic requirements
- decr pleural/pericardial effusions
- decr inflammatory markers
105
What is the choice induction agent for emergent cardiac tamponade surg?
ketamine
106
What is Beck's triad?
for tamponade:
1. hypoT
2. incr CVP
3. distant heart sounds
107
What is pulsus paradoxus?
decr in SBP >12 mmHg during inspiration
hallmark for tamponade
108
What EKG changes are seen with tamponade?
- electrical alternans (also seen with pericardial effusion)
| - low-voltage QRS complexes
109
What do you see with PAC measurements in patients with tamponade?
PAOP = PAP = CVP
pressures equalize in heart
110
What are the hemodynamic goals when caring for someone with tamponade?
- incr HR/contractility to maintain preload
- incr afterload to maintain BP
- incr preload to promote filling
111
What do you use for patients with decreased CO in setting of isolated AI?
dobutamine
112
How do you want to keep someone's hemodynamics with PMH isolated AI?
"full, fast, forward"
- HR 80-100
- maintain preload
- decr afterload to promote fwd flow
but excessive tachy can => myo. ischemia
113
What two hemodynamic issues can increase regurgitant volume in AI?
1. bradycardia
| 2. increased SVR
114
A 75 yo man with aortic stenosis and coronary artery disease has a preinduction HR of 68 and a BP of 125/70. After induction with fentanyl, versed and pancuronium, the HR is 90 and the BP is 85/45. ECG shows new ST elevation in lead II. Most appropriate initial management is with what agent?
phenylephrine
115
After a ground level fall, a 65 year-old woman with severe aortic stenosis develops atrial fibrillation. Vital signs include HR 150 and irregular with BP 50/20 mmHg. The MOST appropriate initial treatment is
what?
synchronized cardioversion (unstable brady)
116
What is a specific anesthetic contraindication in patients with severe AS?
spinals/epidurals
if sympathetic block to T6, can cause decreased afterload
117
Hemodynamic goals in patients with AS?
- sinus rhythm at all costs
- keep HR 60-80
- maintain both preload/afterload
118
Hemodynamic goals in pts with MR?
"full, fast, forward" (like AI)
- HR goal 80-100
- avoid brady and acute incr in afterload
119
What can cause worsened regurgitant flow in MR?
- bradycardia
- acute incr in afterload
- excessive volume (can dilate LV)
120
A patient with a history of mitral stenosis but without evidence of congestive heart failure presents for emergency appendectomy. The patient’s EKG shows normal sinus rhythm, blood pressure is 140/85 mmHg, and heart rate is 105 beats/min. What would you give?
start beta-blocker
121
A 45 yo woman with mitral stenosis is scheduled for elective mitral valve replacement. 2 minutes after tracheal intubation, she develops new onset Afib with a rapid ventricular response of 150 bpm and a decrease in BP to 75/45. Which of the following is the most appropriate 1st step in management?
electrical cardioversion
if pt suddenly develops new rhythm and BP is unstable, ALWAYS SHOCK
122
Hemodynamic goals for MS?
- HR low (60-80)
- avoid large incr in CO
- preload incr but not fluid-overloaded
123
What is an issue that can happen in patients with MS?
LA dilated => promotes SVTs, esp afib
124
What do you do with the following in stenotic valvular lesions:
- preload
- afterload
- HR
MS, AS:
- preload: maintain
- afterload: maintain
- HR low
125
What do you do with the following in regurgitant valvular lesions:
- preload
- afterload
- HR
MR, AR:
- preload: keep high
- afterload: keep low
- HR high
126
What do you do with the following in tamponade:
- preload
- afterload
- HR
- preload: high
- afterload: high
- HR: high
127
What do you do with the following in HOCM/SAM:
- preload
- afterload
- HR
- preload: high
- afterload: high
- HR: low
128
What do you see on echo in patient with HOCM, in terms of the heart structure?
left ventricular hypertrophy (LV wall thickness > 15mm) in the absence of an enlarged ventricular cavity
can also be asymmetric septal hypertrphy
129
What are some other names for HOCM?
- asymmetric septal hypertrophy
| - idiopathic hypertrophic subaortic stenosis
130
What do you see on echo in patient with HOCM, in terms of valvular issues?
SAM = systolic anterior motion of MV
131
Where is murmur for HOCM best heard?
left lower sternal border and apex
132
What increases HOCM murmur?
decr ventricular filling (Valsalva)
133
What improves HOCM murmur?
squatting
134
How is HOCM inherited?
autosomal dominant
135
Hemodynamic goals for HOCM?
- incr preload
- maintain afterload
- maintain NSR
- AVOID inotropes
136
What do you do preop for acute AR if:
- CI >2.1
- PCWP <18
nothing, just induce
137
What do you do preop for acute AR if:
- CI >2.1
- PCWP >18
diuretic
138
What do you do preop for acute AR if:
- CI <2.1
- PCWP <18
incr preload with fluids
139
What do you do preop for acute AR if:
- CI <2.1
- PCWP >18
inotrope
140
A healthy subject has indwelling arterial catheters simultaneously transducing pressures from the brachial, radial, femoral, and dorsalis pedis arteries. Which of the catheters is likely to record the HIGHEST systolic pressure?
dorsalis pedis
141
What does pulsus alternans indicate?
LV failure
142
What does collapsing pulse indicate?
- AR
| - hyperdynamic circulation
143
What does pulsus biferens indicate
- AR
| - HOCM
144
What does anacrotic pulse indicate
aortic stenosis
145
____ = arterial waveform seen with LV failure
pulsus alternans
146
____ = arterial waveform seen with AR or hyperdynamic circulation
collapsing pulse
147
____ = arterial waveform seen with AR or HOCM
pulsus biferens
148
____ = arterial waveform seen with AS
anacrotic pulse
149
A 32 yo man who is 5 years post heart transplant for cardiomyopathy is tachycardic at baseline on pre-op evaluation. What is the cause?
cardiac denervation
no sympathetic/parasympathetic input
preload dependent, but do respond to circulating catecholamines
150
What two agents can increase HR in post-tx patients?
1. epi
| 2. isoproterenol
151
What do you see on EKG of post-tx patients?
2 P waves (d/t 2 SA nodes)
152
What are some issues with post-tx cardiac health?
1. accelerated atherosclerosis
| 2. silent MI (no pain sensors)
153
What's the goal SBP range with aortic dissection?
90-120
to reduce aortic wall stress
154
What is/are the drug(s) of choice for BP maintenance in aordic dissection?
- sodium nitroprusside
- beta blockers
DON'T use nitroprusside alone, as it may raise shearing forces
155
A 55 yo man with a history of cocaine abuse presents to the operating room with a Stanford type A aortic dissection. He is awake, alert, and complaining of chest pain. His blood pressure is 75/40 mmHg, pulse 105 bpm, SaO2 95% on 2L nasal cannula. A 12 lead EKG reveals ST elevation in leads II, III, and aVF. An echocardiogram reveals large pericardial fluid with right ventricular compression during systole. What is the BEST initial management strategy for this patient?
surgical repair
156
A 58 yo woman is admitted to the intensive care unit after open repair of a type-III thoracoabdominal aortic aneurysm. Preoperatively, an intrathecal catheter was placed for cerebrospinal fluid drainage. Estimated blood loss was 6L, and PRBCs, cell saver blood, platelets, FFP, and cryoprecipitate were administered to treat anemia and coagulopathy. Postoperatively, the patient is unable to move her lower extremities. Sensation is normal. She has no back pain. What is MOST likely to account for her neurologic deficit?
anterior spinal a. syndrome
157
A 56 yo patient is undergoing a thoracic aortic aneurysm repair with the use of an aortic cross clamp. What vessel provides blood supply to the anterior 2/3 of the spinal cord?
artery of Adamkiewicz
158
What situation is MOST likely the cause of paraplegia following repair of a descending thoracic aortic aneurysm?
prolonged aortic cross-clamp time
159
What three vessels supply the spinal cord?
1. anterior spinal a: ant 2/3 of cord
2. posterior spinal aa: post 1/3 of cord
3. artery of Adamkiewicz (arteria radicularis magna): thoracolumbar radicular a. off aorta that is major blood suppy to anterior, lower 2/3 of spinal cord
160
____: loss of motor fxn (paralysis, ataxia) and sensation below lesion
Brown-Sequard syndrome
- lateral hemisection/transection of spinal cord
- spinothalamic tract, one or both dorsal columns and corticospinal tract
161
____: loss of motor fxn/pinprick sensation with preservation of vibration and proprioception
anterior spinal a. syndrome
- usually d/t ischemia or dissection
- bilat spinothalamic tract and corticospinal tract
162
What part of spinal cord is affected by anterior spinal a. syndrome?
bilat spinothalamic tract and corticospinal tract
163
What part of spinal cord is affected by Brown-Sequard syndrome?
spinothalamic tract, one or both dorsal columns, corticospinal tract
164
What are the two main causes of anterior spinal artery syndrome?
1. ischemia
| 2. dissection
165
What are the two overall methods of classifying aortic dissections?
1. Stanford
| 2. DeBakey
166
What are the two types of aortic dissections per the Stanford classification?
1. type A = ascending aorta
| 2. type B = descending aorta
167
What are the three types of aortic dissections per the DeBakey classification?
1. type I: ascending aorta, aortic arch, and descending aorta
2. type II: ascending aorta
3. type III: descending aorta distal to L subclavian a.
168
What are some signs of PE in the OR?
- hypoT
- hypoxemia
- bronchospasm
- decr etCO2
- incr CVP
- incr PAP (not PAOP)
169
A patient with a history of hypertension (baseline blood pressure 160/100 mmHg) experiences an acute myocardial infarction (MI). What risk factor is MOST likely to be associated with an increased risk of developing cardiogenic shock following an acute MI?
ST segment elevation MI
170
The diagnosis of cardigenic shock is established and the decision is made to institute intra-aortic balloon counterpulsation. What parameter is MOST likely to decrease as a result of this intervention?
LV afterload
171
What happens to each of the following in hypovolemic shock:
- HR
- MAP
- CVP
- PAOP
- SVR
Hypovolemic:
- HR = incr
- MAP = decr
- CVP = decr
- PAOP = decr
- SVR = incr
172
What happens to each of the following in cardiogenic shock:
- HR
- MAP
- CVP
- PAOP
- SVR
Cardiogenic:
- HR = incr
- MAP = either
- CVP = nml (LV fail) or incr
- PAOP = nml (RV fail) or incr
- SVR = incr
173
What happens to each of the following in distributive shock:
- HR
- MAP
- CVP
- PAOP
- SVR
Distributive:
- HR = incr (except maybe decr in neurogenic shock)
- MAP = decr
- CVP = decr/nml early, incr/nml late
- PAOP = decr/nml early, incr/nml late
- SVR = decr
174
What happens to each of the following in obstructive shock:
- HR
- MAP
- CVP
- PAOP
- SVR
Obstructive:
- HR = incr
- MAP = decr
- CVP = incr
- PAOP = incr
- SVR = incr
175
What defines severe sepsis?
sepsis + organ dysfxn
176
What differentiates SIRS from sepsis?
infectious etiology = sepsis
177
What defines septic shock?
sepsis + hypoT
178
What patients need endocarditis prophylaxis?
- prosthetic cardiac valve
- previous IE
- CHD (unrepaired cyanotic CHD, repaired CHD with prosthetics or within 1st 6 mo, or repaired with residual defects)
- heart tx with cardiac valvulopathy
179
What procedures need endocarditis prophylaxis in appropriate pts?
- dental procedures with gum manipulation/perf of mucosa
| - procedures on resp tract, infected skin or muskuloskeletal tissue
180
What is a component of protocol for early (first 6 hrs) goal-directed therapy in tx sepsis?
central venous oxygenation sat of at least 70%
181
____ view is the most optimal TEE view to monitor intraop myocardial ischemia.
transgastric short axis
provides view of all 3 coronary a distributions
182
What is the primary cause of neurologic deficit following CEA?
thromboembolism
183
What's the best method to check for cerebral perfusion during CEA?
EEG
184
Following a carotid endarterectomy in a 72 year old man, the nurse in the postanesthesia care unit calls you to report the patient’s blood pressure is 220/103. His preoperative pressure was 140/80 mmHg. This is MOST likley due to denervation of what structure?
carotid sinus
185
What are the indications for CEA?
- TIAs with >70% occlusion
- severe stenosis with minor CVA
- mod occlusion (30-70%) in pts with ipsilat sx
186
What is the role of a shunt in CEA?
can place if signs of cerebral ischemia, but carry risk of thromboembolism
187
What is the major cause of mortality post-CEA?
myocardial ischemia (1-2%)
188
What are four types of post-op complications in CEA, and why?
1. HTN: pain, hypoxemia, hypercarbia, surgical denervation of ipsilat carotid baroR (carotid sinus)
2. hypoT: removal of atheroma exposes baroR (carotid sinus) to higher BP, causing brain stem-mediated hypoT/brady
3. resp insufficiency: damaged to recurrent laryngeal n, impaired carotid body response to hypoxemia
4. neuro deficits: thromboembolism (causing cerebral hypoperfusion), regional cerebral hyperperfusion
189
After termination of cardiopulmonary bypass, a patient who is chronically digitalized receives digoxin 0.5 mg in error. An EKG shows sinus brady with intermittent sinus arrest. Blood pressure is 90/60. What BP drug is contraindicated?
calcium chloride
190
What electrolyte abnormalities are associated with digoxin toxicity?
Dig Tox May Keep Coming Back:
- decr Thyroid
- decr Mag
- decr K
- incr Ca
- incr BUN
191
What are the factors looked at with the RCRI?
- ischemic heart dz
- CHF
- CVA
- Cr > 2.0
- IDDM
- high-risk surg
if 3 or more, consider more workup
192
If you have 2 RCRI factors, risk of cardiac complications is __%, whereas with 3 RCRI factors it is __%.
```
2 = 7% risk
3 = 11% risk
```
193
What innervates diaphragm?
phrenic n. (C3-C5)
194
How much does unilat phrenic n. injury affect pulm fxn?
25%
195
What does general anesthesia do to O2 consumption and CO2 production?
reduces VO2 and VCO2 by 15% (mostly within cerebral/cardiac metab)
196
What effect does vagus n. have on lungs?
parasympathetics via muscarinic Rs:
- bronchoconstriction
- incr bronchial secretions
197
What type of sympathetic Rs are present in lung tissue, and what are their actions?
- beta-2: bronchodilation, decr bronchial secretions
| - alpha-1: decreased secretions, maybe bronchoconstriction
198
How do sympathetics/parasympathetics act on lung vasculature?
sympathetic:
- alpha-1: vasoconstrxn
- beta-2: vasoD
parasympathetic:
-vasoD via nitric oxide
199
Formula for transpulmonary gradient
P(transpulm) = P(alveolar) -- P(intrapleural)
+5 at end expiration, -4 at inspiration (gradient)
200
A patient under general anesthesia maintains saturation levels of 85-90%. Despite 100% oxygen therapy the saturation does not rise above 90%. What is the MOST likely reason?
methemoglobinemia
201
What 6 things cause left shift on O2-Hgb dissociation curve?
1. hypothermia
2. alkalosis
3. decreased 2,3-DPG
4. fetal Hgb
5. carboxyHgb
6. methemoglobin
202
What 6 things cause right shift on O2-Hgb dissociation curve?
1. hyperthermia
2. acidosis
3. incr 2,3-DPG
4, abnormal Hgb
5. incr CO2
6. pregnancy
203
What effect does the following have on the O2-Hgb dissociation curve:
hypothermia
left shift
204
What effect does the following have on the O2-Hgb dissociation curve:
alkalosis
left shift
205
What effect does the following have on the O2-Hgb dissociation curve:
decreased 2,3-DPG
left shift
206
What effect does the following have on the O2-Hgb dissociation curve:
fetal Hgb
left shift
207
What effect does the following have on the O2-Hgb dissociation curve:
carboxyHgb
left shift
208
What effect does the following have on the O2-Hgb dissociation curve:
methemoglobin
left shift
209
What effect does the following have on the O2-Hgb dissociation curve:
hyperthermia
right shift
210
What effect does the following have on the O2-Hgb dissociation curve:
acidosis
right shift
211
What effect does the following have on the O2-Hgb dissociation curve:
increased 2,3-DPG
right shift
212
What effect does the following have on the O2-Hgb dissociation curve:
abnormal Hgb
right shift
213
What effect does the following have on the O2-Hgb dissociation curve:
incr CO2
right shift
214
What effect does the following have on the O2-Hgb dissociation curve:
pregnancy
right shift
215
What is normal lung compliance?
150 - 200 ml/cm H2O
216
Formula for lung compliance
change in lung vol/change in transpulm pressure
217
formula for chest wall compliance
change in chest vol/change in transthoracic pressure
218
Name three factors that reduce lung compliance
1. pulm fibrosis
2. pulm edema
3. consolidation
compliance incr by emphysema
219
Name three factors that reduce chest wall compliance
1. severe obesity
2. laparoscopy
3. incr abd pressure
220
Name 5 intraop issues that can decrease lung compliance
1. mainstem intubation
2. bronchospasm
3. pneumo
4. changes in position
5. insufflation of abd
221
What does it mean when the compliance curve is shifted to the R?
addition of PEEP
222
What does it mean when the compliance curve is flattened?
incr airway resistance
223
What does it mean when the compliance curve doesn't return to zero?
leak
224
What lung measurement can be made with an IS?
inspiratory reserve volume
225
What effect does obesity have on the following:
| pulm compliance
decr
226
What effect does obesity have on the following:
| FRC
decr
227
What effect does obesity have on the following:
| vital capacity
decr
228
What effect does obesity have on the following:
| TLC
decr
229
What effect does obesity have on the following:
| expiratory reserve volume
decr
230
What effect does obesity have on the following:
| residual volume
unchanged
231
What effect does obesity have on the following:
| closing capacity
unchanged
232
What effect does obesity have on the following:
| O2 consumption
incr
233
What effect does obesity have on the following:
| CO2 production
incr
234
What is the average adult tidal volume?
500 mL
235
What is the average adult inspiratory reserve volume?
| What does IRV mean?
3000 mL
max additional vol that can be inspired above TV
236
What is the average adult expiratory reserve volume?
| What does ERV mean?
1100 mL
max vol that can be expired below tidal vol
237
What is the average adult residual volume?
| What does RV mean?
1200 mL
vol remaining after max exhalation
238
What is the average adult TLC?
| Formula for TLC?
5800 mL
RV + ERV + Vt + IRV
239
What is the average adult FRC?
| Formula for FRC?
2300 mL
RV + ERV
240
What is closing capacity?
volume that small airways and alveoli begin to close in dependent parts of lung
incr with age
241
What is the normal ratio of FEV1/FVC?
>80%
242
What is a shunt?
desaturated, mixed venous blood from R heart returns to L heart without being oxygenated
243
If minute ventilation remains constant, what happens to PetCO2 and PaCO2 will result from a decrease in cardiac output?
PetCO2 decreases
PaCO2 increases
244
What are three factors that can incr physiological dead space?
1. decreased CO
2. PE
3. upright position
