Exam 3 ppt key points Flashcards
1
Q
What are the Risk Factors for CAD
A
Age Gender (Male) Family Hx Smoking- 6x greater in women, 3x greater in males HTN High Cholesterol- high LDL & low HDL Diabetes Obesity Physical Inactivity Stress
2
Q
At the center of the cardiovascular system is ?
A
the heart.
3
Q
Myocardial blood supply is derived entirely from ?
A
the right and left coronary arteries.
4
Q
The left coronary normally supplies
A
the LA, interventricular septum, and LV.
5
Q
The right coronary normally supplies
A
the RA, most of the RV, and variable amounts of LV.
6
Q
The most frequently performed cardiac operation is?
A
Coronary artery bypass grafting
7
Q
CABG technique involves bypass of a narrowed or occluded epicardial coronary with a small-diameter conduit distal to the narrowed segment. Selected grafts include?
A
reversed saphenous
internal mammary artery
8
Q
___________ appears to have superior long-term performance with 90% patency rates at 10 years.
A
The IMA
9
Q
The choice of conduit in CABG depends on?
A
availability and durability
50% of vein grafts will be significantly diseased or occluded at 10 years.
The IMA appears to have superior long-term performance with 90% patency rates at 10 years.
10
Q
When using a saphenous vein graft in CABG, the proximal arterial inflow source is?
A
the ascending aorta.
11
Q
When the LIMA is utilized in CABG, the proximal arterial inflow source is
A
the left subclavian artery.
12
Q
_________ is used to replace the function of the heart in CPB
A
Arterial pump
13
Q
Arterial pump generally uses one of two primary technologies
A
A roller pump
A centrifugal pump – thought to be less traumatic
14
Q
Identify the correct order of steps to CPB
A
- Priming
- Anticoagulation
- Cannulation
- Initiation
- Maintenance
- Weaning and Termination
15
Q
The solution used to prime the CPB circuit is generally _______
A
a balanced electrolyte solution
16
Q
Hemodilution in CPB is due to?
A
Prime volume
17
Q
Standard procedure requires that the patient be ___________ before cannulation for CPB. _______ is still the standard agent used.
A
fully anticoagulated
Heparin
18
Q
Heparin administered through a central venous catheter at an initial dose of ________ for CPB
A
300 U/kg
19
Q
Heparin Onset is almost immediate, but generally the drug is allowed to circulate for ______________ before it’s effect is measured.
A
3-5 minutes
20
Q
The ACT must increase to at least _______ before CPB is initiated.
A
300 seconds
400 for most institutions
21
Q
The ACT is not used to monitor heparin levels but to monitor __________
A
the anticoagulant effects of heparin and other anticoagulants.
22
Q
Elevated ACT measurements taken, before, during, or after CPB may be influenced by variables other than heparin which include?
A
Hypothermia
Hemodilution
Aprotinin
23
Q
Every CPB procedure requires a high-flow cannula in a large vein and another in a large artery for withdrawing blood from and returning blood to the patient. The target for venous cannulation is ?
A
RA- It’s appendage is conveniently accessible through a sternotomy.
The RA may also be approached through the femoral vein.
24
Q
For CPB venous cannulation, the right atrium can be accessed through?
A
appendage is conveniently accessible through a sternotomy.
The RA may also be approached through the femoral vein.
25
The CPB circuit returns oxygenated blood to the patient through the arterial cannula.
For CABG procedures, the standard target for the arterial cannula is ?
the portion of the ascending aorta below the aortic arch but still 3-4 cm above the aortic valve.
26
Which patients require direct left ventricular venting in CPB
patients with severely compromised ventricular function undergoing CABG
Patients undergoing any intracardiac procedures
Patients with aortic insufficiency
27
left ventricular venting in CPB may be necessary for patients with aortic insufficiency because?
The LV vent is separate from the cardioplegia cannula, it can be used to decompress the heart during antegrade cardioplegia administration.
28
LV vents are typically introduced through ?
the right superior pulmonary vein and advanced through the LA, across the mitral valve, and into the LV
29
What is the indication that the venous cannula is adequately draining the venous return to the heart?
right sided heart pressure (CVP and PAP) should decrease to O mmHg and become nonpulsatile.
30
During CPB initiation describe arterial BP and arterial tracing
Arterial blood pressure should reach a normal mean pressure (60-90 mmHg) while also becoming nonpulsatile.
The arterial tracing usually becomes nonpulsatile as the heart is emptied and the pumping force is changed from the ventricle to the nonpulsatile arterial pump of CPB machine.
31
During CPB initiation, the heart is arrested in diastole by ?
the administration of potassium enriched cardioplegia solution to the heart.
32
__________ is the single most important step in reducing the heart’s myocardial oxygen consumption by 90%.
Interrupting myocardial electromechanical activity
33
Reduction in myocardial consumption by cardioplegia during CPB is augmented by?
Hypothermia at 22 degrees C
This is achieved by administering cold cardioplegia solution.
34
The combined influence of potassium arrest and myocardial temperatures lower than 22 degress C reduces myocardial oxygen consumption by ________% and enables the tissue to withstand complete interruption of blood flow for periods of ________________
97%
20-40 minutes.
35
For induction of cardioplegic arrest, a “high-K” solution with a potassium concentration of approximately ____________ is used.
20-30 mEq
36
What are the characteristic of the cardioplegia solution during initiation
Has a potassium concentration of approximately 20-30 mEq.
Designed to be slightly hypertonic to reduce edema.
Include a buffer to counter the heart’s production of acidic metabolites.
Contains a substrate for energy or catalysts to assist the heart’s production of ATP.
37
Maintenance phase of CPB entails
After isoelectric arrest is induced, the solution is changed to a “low-K” mixture with a potassium concentration of about 10 mEq.
Periodically throughout the procedure, 200-500 mL doses of “low-K” solution are administered to deliver nutrients to the cells and maintain the potassium concentration.
Cardioplegia can be administered antegrade into the coronary arteries via the aortic root, or retrograde into the coronary sinus/veins.
The most complete technique for myocardial protection involves both antegrade and retrograde delivery.
38
What is the potassium concentration of cardioplegia solution during CPB.
10 mEq
39
Cardioplegia can be administered antegrade into the coronary arteries via ___________, or retrograde into ________.
the aortic root
coronary sinus
40
Immediately after termination of CPB, the patient is often hemodynamically supported with?
volume (blood, albumin, crystalloids, hespan)
frequently supplemented with vasopressors or inotropic agents.
41
During the weaning and termination phase of CPB, when the patient is hemodynamically stable, protamine can be administered to reverse the anticoagulant effect of Heparin. Protamine dose is ?
1mg / 100 units Heparin given.
42
What is the primary concern during induction of a patient for CABG
Prevention of myocardial ischemia
43
Two factors associated with myocardial ischemia include
Inadequate oxygen supply (coronary lesions)
Excessive oxygen demand (HR, BP, Adrenergic stimulation)
44
Patients with _____________ are more susceptible to insult during induction.
disease of the left main coronary
45
Many cardiac patients require fluid loading or prophylactic treatment with pressors during induction because?
They have low circulating blood volumes because of hypertensive vasoconstriction.
Small doses of phenylephrine or ephedrine may be necessary to avoid excessive hypotension.
46
The lungs must be deflated to prevent laceration or puncture during sternotomy for how long
for approximately 15-20 seconds
47
Bolus administration of heparin through the central line may decrease arterial pressure by _________?
10-20%.
48
ACT should be approximately __________ before it is safe to institute CPB
400 seconds
49
Anticoagulation is measured _______ after heparin bolus by ACT.
3-5 minutes
50
Aortic cannulation is associated with hypertensive response, probably because of?
Direct stimulation of sympathetic nerves in the aortic arch.
51
___________ assists aortic cannulation and prevents laceration of the aorta.
Reduction in MAP
52
Venous cannulation may lead to?
Fluctuations in arterial pressure and ventricular tachyarrhythmias secondary to manipulation of the heart.
53
CPB should not commence unless the following have been completed by the anesthesia provider:
Heparin administered
ACT checked and at least 350-400
Adequate muscle relaxation
Inotropic infusions turned off
Pupil symmetry assessed for later comparison
Pulmonary artery catheter pulled back 5 cm
Urinary output emptied before bypass
54
During CPB initiation, the clamps placed across the cannulas during insertion are removed in what sequence?
venous, then arterial
55
Multiple events occur simultaneously and can cause a significant drop in blood pressure at the initiation of CPB. They are?
Preload to the heart decreases causing a loss of stoke volume, while hemodilution decreases blood viscosity and dilutes catecholamines in the plasma contributing to the drop in pressure.
56
During CPB initiation, rapid cooling of the patient occurs to a target temperature of ?
28 degrees C
57
ACT is checked every __________ by the perfusionist and is maintained at _________ with the addition of heparin.
30-45
>400 seconds
58
While most think CPB is break time, it is NOT! Why?
```
Swan migration
Paralysis
Amnesia
MAP
pH
Urine output
Glucose
```
59
What is the checklist for weaning from CPB?
Patient is warm, at least 35 C
Heart rhythm has returned
HR 70-100. < 60 reduced CO; > 120 reduced LV filling
Inflate lungs
Labs: K+, iCa++, Hct, pH, ACT
Drugs: Lidocaine, Calcium, Magnesium
60
When the patient is weaned from CPB, considerations should include
the ventricular function of the heart before bypass
the length of time the aorta was cross-clamped.
61
3 Basic Groups Coming Off Bypass
Patients with good ventricular function
Hypovolemic patients
Patients with pump failure
62
Features of hypovolemic patients (mixed group) coming off CBP
Respond quickly to 100 mL aliquots of pump blood, FFP, or PRBC’s. BP and CO rise with each bolus, sustainable. LVEDP below 10-15 mmHg.
Impairment should be suspected when LVEDP rises with volume infusion without appreciable changes in BP or CO. These patients require LVEDP above 10-15 mmHg
63
Features of patients with pump failure coming off CBP
Sluggish, poorly contracting heart that progressively distends.
Inotropic therapy is initiated. If SVR is high, afterload reduction can be tried along with inotropic therapy.
Ultimately, CPB may need to be reinstituted.
64
This drug does not increase filling pressure and may be associated with less tachycardia. CO often increases without significant changes in blood pressure.
Dobutamine
65
If inotropes and afterload reduction fail during separation from CPB
CPB may be used as a bridge to an intra aortic balloon pump.
66
This drug improves renal blood flow (low doses) and is often more effective in raising blood pressure than in raising CO.
Dopamine
67
Clinically is the most potent inotrope and is usually effective in increasing both cardiac output and systemic blood pressure when other agents have failed. In low doses, it predominantly has beta-agonist activity.
Epinephrine
68
Large doses of this drug compromise renal blood flow.
Norepinephrine
69
Amrinone and Milrinone
Both are phosphodiesterase inhibitors; inotropes with significant arterial and venodilator properties.
Unlike other inotropes, these two inodilators may not appreciably increase myocardial oxygen consumption because they decrease left ventricular afterload and do not directly increase HR.
70
Two inotropes that may not appreciably increase myocardial oxygen consumption because they decrease left ventricular afterload and do not directly increase HR.
Amrinone and Milrinone (phosphodiesterase inhibitors)
71
Chest tube drainage in the first 2 hours of more than ___________ in the absence of a hemostatic defect, is excessive.
250-300 mL/hr (10mL/kg/hr)
72
Assess pupils after initiation of CPB as unilateral dilation may indicate
arterial inflow into the innominate artery (unilateral carotid perfusion).
73
Protamine should be administrated slowly over a period of ____________ to reduce the risk for hypotension
5-10 minutes
74
If the heart fibrillates during rewarming, _________ may be necessary.
defibrillation (5-10 J)
75
What is given to decrease the likelihood of fibrillation during rewarming
lidocaine 100-200 mg and magnesium sulfate 1-2 g
76
A-line placement when LIMA is being used for CABG
If the left mammary artery is to be harvested, A-line placement is best suited in the right radial artery because retractors can dampen the waveform of a left radial A-line.
77
Heparin is always administered before
cannulation
78
The PA catheter should be pulled back 3-5 cm to
minimize the risk of pulmonary perforation as the pulmonary arteries collapse with the initiation of CPB.
79
What is desirable SBP during termination of CPB
After termination of CPB, elevated SBP should be avoided to prevent excessive stress on suture lines in the heart and aorta. Usually 90-120 mmHg is a desirable systolic pressure.
80
___________ is frequently implicated in post-bypass bleeding.
Platelet dysfunction
81
Amicar dose
10-29 gm load
| 1-2 gm/hr
82
Stroke is predominant CNS postop complication of CABG. Indicators are
Visual impairment
Hemiparesis
Aphasia
Sensory impairment
83
CNS complications after CPB is Usually seen in, pump runs longer than?
90 minutes.
84
Cause of coagulopathy after CPB
Platelet dysfunction is frequently implicated
Thrombin production and fibrinolysis. Thrombin is produced by the extrinsic and intrinsic pathways and by activated platelets. It is only partially suppressed by heparin therapy.
85
__________ is the single most important intraoperative monitor of renal system during CABG
Urinary output
Standard is UO of 1 mL/kg/hr.
86
Renal dysfunction in CPB is related to?
length of time on bypass (longer than 3 hours)
cardiac output
Infection
Type of procedure (valve surgery has higher risk)
Excessive blood loss
Diabetes
Increased use of vasopressors
Perioperative myocardial infarction
Use IABP
Massive transfusions
87
Hypothermia during CPB depresses renal tubular function; however what interventions will result in adequate urine output?
hemodilution
use of mannitol
maintenance of GFR
88
Hyperglycemia during CPB can also affect ________
renal tubules
89
During CPB, as the temp is decreased to 28 C what happens
ACT, PT, and PTT are prolonged
platelets become nonfunctional
Cellular potassium uptake is increased and may result in hypokalemia.
90
The beneficial aspects of hypothermia include
a reduced basal metabolic rate
improved myocardial protection
tissue and organ preservation
reduced oxygen consumption.
91
The metabolic requirement for O2 is reduced by _________ for each ________ drop in core body temperature.
50%
7° C
92
It may not be possible to convert heartbeat to normal sinus rhythm until the rewarming core temperature is _______
34°C.
93
Normal stroke volume
60-90mL/beath
94
Normal stroke index
40-60 mL/beat/m2
95
Normal cardiac output
5-6 L/min
96
Normal Cardiac index
2.5 - 4 L/min/m2
97
Normal SVR
700-1400 dyne/sec/cm5
SVR=(MAP-CVP) /(CO x 80)
98
Normal PVR
50-300 dyne/sec/cm5
| SVR=(PAP-PCWP) /(CO x 80)
99
Left ventricular stroke work index
40-60 g•m/beat/m2
100
Coronary perfusion pressure
50 mmHg
101
Normal EF
55-70%
102
Rate-pressure product
>15000
103
Tripple index
>180,000
104
Thoracic surgery focuses on the chest organs which are?
Heart
Lungs
Esophagus
Trachea
105
a surgical procedure to gain access into the pleural space of the chest
Thoracotomy
106
Lung function testing: 80-40-15 rule:
FEV1 and DLCO > 80% = no additional testing needed. If < 80 or dyspnea present , diffusing capacity and postoperative function should be predicted.
PPO FEV1 and DLCO < 40% = increased risk; exercise testing should be evaluated
VO2 max < 15 ml/kg per min = increased risk
107
___________ is the leading cause of cancer deaths in the United States
Bronchogenic carcinoma
108
The incidence of of lung cancer is ________ among COPD patients than in the general population.
four times higher
109
Many patients presenting for lung surgery will have complex underlying pathology. Therefore, ______________________ are crucial to anticipating the patient’s intraoperative and postoperative needs.
Evaluating respiratory function and predicting post resection function
110
The Anesthetic risk assessment for patients in need of pulmonary resection surgery specific to pulmonary surgery focuses on
how the underlying pathology will challenge the maintenance of adequate gas exchange and general homeostasis under OLV
The potential for post op respiratory failure to make weaning and extubation difficult
111
OLV is commonly provided by three different methods:
Double lumen tubes
Bronchial blockers
Single lumen endobronchial tubes
112
The principal advantage of double-lumen tubes are
relative ease of placement
the ability to ventilate one or both lungs
the ability to suction either lung
113
All DLTs share the following characteristics:
Longer bronchial lumen that enters either the right or left main bronchus and another shorter tracheal lumen that terminates in the lower trachea.
A preformed curve that when properly “aimed” allows preferential entry into a bronchus
A bronchial cuff
A tracheal cuff
114
Principal Disadvantages of Double Lumen Tubes are
Size selection
Difficult to place in patients with difficult airways
Not optimal for postoperative ventilation (must be changed out if pt to remain intubated)
115
The most commonly used DLTs are available in several sizes:
35 FR to 37 Fr for women over 160 cm
37 FR to 39 Fr for men less than 175 cm
39 Fr to 41 for men over 175 cm
116
Even slight movement of the right DLT can lead to malpositioning because?
The distance from the carinal bifurcation to the right upper lobe is 1.5-2 cm, compared to 4-5 cm left mainstem bronchus
117
Many practitioners have resolved to using left DLTs for all right and left thoracotomies unless a left sided tube is contraindicated by?
lesions of the airway
compression of the trachea or main bronchi by external mass.
118
The most common complication associated with a DLT is
malpositioning
119
The larger size of the DLT is probably also responsible for?
the slightly increased incidence of hoarseness and vocal cord lesions observed following DLT vs bronchial blocker.
120
Correct steps for Auscultation of Breath Sounds After Placement of a Double Lumen Tube
Inflate tracheal cuff
Verify bilateral breath sounds
Inflate the endobronchial cuff
Clamp Y-piece to endobronchial lumen and open to atmosphere
Verify breath sounds (tracheal side) absence (bronchial side)
Unclamp and reconnect the endobronchial lumen and verify breath sounds
Repeat above steps except this time Clamp y-piece on tracheal lumen
121
Fiberoptic Bronchoscopy to Verify Placement of a Double Lumen Tube
Insert the scope through the tracheal lumen. Visualize the cirina distally
Visualize the bronchial (blue) cuff 1-2 mm beyond the carina. Ensure that the cuff is not too proximal or overinflated
Insert the scope through the bronchial lumen. Visually confirm that the tip of the bronchial lumen is unobstructed.
For left sided tubes, visualize the bronchial carina distal to the tube tip.
For right sided tubes with a right upper lobe ventilation port, visualize the the right upper lobe bronchus is aligned with the ventilation port
122
The bronchial blocker must be advanced, positioned, and inflated under direct visualization via flexible bronchoscope. T/F
True
123
The major advantage of a single-lumen tube with a bronchial blocker is?
Unlike a double lumen tube, it does not need to be replaced with a conventional tracheal tube if the patient is to remain intubated.
124
Advantages of bronchial blockers over DLT
Because insertion of a DLT is more complicated, bronchial blockers are more useful in patients with a difficult airway or a tracheostomy.
These devices are beneficial for patients who are already intubated.
They are used for pediatric lung separations
125
Disadvantages of bronchial blockers compared to DLT
Positioning of the bronchial blocker requires more time than the DLT
Bronchial blockers have a greater incidence of becoming malpositioned
Bronchial blockers do not allow suctioning
126
During two-lung ventilation, blood flow to the dependent lung averages approximately ______
60%.
127
When one lung is allowed to deflate and one lung ventilation (OLV) is started, any blood flow to the deflated lung becomes ____________
shunt flow, causing the PaO2 to decrease.
128
Without autoregulation of pulmonary blood flow, a __________% shunt would be anticipated.
40%
129
a compensatory mechanism of increasing vascular resistance in hypoxic areas of the lungs, and this diverts some blood flow to areas of better ventilation and oxygenation.
HYPOXIC PULMONARY VASOCONSTRICTION
130
Hypoxic pulmonary vasoconstriction (HPV) is?
the mechanism by which autoregulation during OLV allows a reflex intrapulmonary feedback mechanism that improves gas exchange and arterial oxygenation.
131
Whereas hypoxemia causes vasodilation in the general circulation, alveolar hypoxia __________
has the opposite effect on pulmonary arteries.
132
HPV is Triggered by?
alveolar hypoxia, not arterial hypoxia
133
HPV Onset and resolution are within seconds following changes in partial pressure of oxygen(PO2). Peak effect occurs within ________
15 minutes
134
May be inhibited by __________ and augmented by __________.
vasodilators
chemoreceptor agonists
135
FACTORS THAT REDUCE EFFECTIVENESS OF HPV
```
Alkalosis
Excessive TV or PEEP
Hemodilution
Hypervolemia
Hypothermia
Prostacyclin
Shunt fraction <20% or >80 %
Vasodilators, phosphodiesterase inhibitors, and calcium channel blocker
Volatile anesthetics > 1.5 MAC
```
136
Patients presenting for lung resection should undergo pulmonary function testing to assess
for airflow limitation
diffusion defect
cardiopulmonary reserve.
the response to bronchodilators for patients who demonstrate obstructive disease
137
The American Thoracic Society considers ______________ post-bronchial therapy to be significant.
12% improvement in forced expiratory volume 1 (FEV1)
138
Guidelines to assess thoracic surgical candidacy are not intended to dictate candidacy for anesthesia. If the patient is a candidate for surgery, it is less likely that there will be anesthetic-specific concerns about pulmonary function that would override the surgical decision.
True
139
A diffusing capacity of the lungs for carbon monoxide (DLCO) less than ______________ has been associated with increased risk of complications following pulmonary surgery.
40 %
140
DLCO has been found to have good specificity but low sensitivity as an independent measurement. ___________________ may provide better reliability than single measures.
The product of the predicted values of DLCO and FEV1
141
__________ testing is a strong predictor of patient outcomes after thoracic surgery.
Maximal oxygen consumption (VO2 max)
142
A VO2 max of ______________ is associated with increased mortality, whereas a VO2 max of ______________ is a favorable finding.
less than 10 mL/kg per min ( or 40% predicted value )
greater than 20 mL/kg per min
143
VO2 max may be roughly estimated by evaluating the patient’s ability to climb five flights of stairs which suggests a VO2 max of ____________.
20 mL/kg per min.
144
Aggressive treatment of acute or reversible components of respiratory disease greatly decreases the risk of postoperative complications. Treatable preoperative conditions include?
infections
excess bronchial secretions
bronchospasm
dehydration
electrolyte imbalance
cigarette smoking (? Vaping)
alcohol abuse
malnutrition.
145
Most research indicates that smoking cessation for less than _________ prior to surgery does not alter risk of complications at all.
4 weeks
146
Some research data suggests that smoking cessation less than 1 month may cause
increases in mucus production, which may increase complications.
147
Should surgery be delayed to allow for adequate period of smoking cessation?
owing to the urgent nature of treating pulmonary carcinoma, delaying surgery to allow for an adequate period of smoking cessation is an impractical goal.
148
For thoracotomies the arterial cannula is generally placed in the
dependent arm where it is more easily stabilized.
149
In mediastinoscopy it is arterial cannula is generally placed
to provide indication of innominate artery occlusion.
( Monitoring perfusion on the right arm with a pulse oximeter or radial artery catheter can detect decreased flow to the brain via innominate artery compression).
150
Positioning for OLV
the lateral decubitus position.
A roll is placed beneath the torso just caudal to the axilla to prevent compression of the neurovascular bundle and forward rotation of the humeral head.
Although called an axillary roll it is better considered an axillary support roll because if positioned in the axilla it could cause compression of the neurovascular area.
Hyperabduction of the arms is prevented to keep the brachial plexus from stretching against the humeral head.
Arms can be separately padded and extended forward on arm boards
The peroneal nerve area is another pressure point area of concern and must be adequately padded, etc
151
Ultra sound transmitted from the transducer into the patient interacts with tissue in four ways:
1. Reflection
2. Refraction
3. Scattering
4. Attenuation
152
Because fat, bone, and air-containing lung interfere with sound-wave penetration, clear transthoracic echocardiogram views are particularly difficult to obtain in patients with
obesity, emphysema, or abnormal chest wall anatomy
153
All TEE probes share several common features. All of the currently available probes use
a multifrequency transducer that is mounted on the tip of a gastroscope housing.
154
The majority of the echocardiographic examination is performed using ultrasound between _____ and ______.
3.5 and 7MHz.
155
In most adult TEE probes, there are two knobs;
one allows anterior and posterior movement, and the other permits side-to-side motion.
156
To ensure the continued safety of TEE, the following recommendations have been made:
The probe should be inserted gently, and if resistance is met, the procedure aborted.
Minimal transducer energy should be used and the image frozen when not in use.
When not imaging, the probe should be left in the neutral, unlocked position to avoid prolonged pressure on the esophageal mucosa.
If possible, the electrical isolation also should be checked.
The probe should be inspected before each insertion for cleanliness and structural integrity.
157
What are the patient history relative contraindications of TEE
```
Dysphagia
Odynophagia
Mediastinal radiation
Recent Upper GI bleed
Recent Upper Surgery
Thoracic Aortic Aneurysm
```
158
What are the pathological relative contraindications of TEE
```
Stricture
Tumor Diverticulum
Varices
Esophagitis
Recent Chest Trauma
```
159
During TEE probe insertion
Can aspirate stomach contents
Can use Laryngoscope for better visual if needed
Should visualize heart at 30 cm
Probe insertion post patient anesthetized and ETT secured (if applicable)
160
During TEE probe insertion the heart should be visualized at _____cm
30cm
161
During manipulation of TEE, the probe is horizontal at what degree?
0 degree
162
TEE PROBE MANIPULATION
Rotating- Left (Counterclockwise) Right (Clockwise) Using large wheel
Small wheel changes plane angle
O degree – horizontal
90 degree- vertical
180 degree- mirror of O degree
163
TEE UE View
Transducer at level of the aortic arch, which is examined in LAX and SAX. In many patients, images of the main pulmonary artery (PA) and pulmonic valve (PV) also may be developed for the TG window.
164
Cerebral blood flow is provided by
internal carotid arteries (80%) and vertebral arteries (20%) (these anastomose at base of brain to from circle of Willis-which provides primary collateral channels)
165
Maintain CO2 at what during CEA
Normocapnia
166
CBF is maintained relatively constant in range of MAP _______
50-150
167
AHA guidelines recommend CEA for asymptomatic pts. with carotid stenosis of ________ if perioperative risk of stroke or death is __________
60-99%
< 3%
168
There are three major branches of the thoracic aorta:
Brachiocephalic artery: Right Common Carotid (Internal carotid, External carotid) Rt Subclavian artery
Left Common Carotid (Internal carotid, External carotid)
Left Subclavian artery
169
The external carotids supply blood to
the face and neck.
170
The internal carotids supply blood to the
brain via the circle of Willis and eyes via the ophthalmic arteries.
171
Before heparin is administered and the internal, external common carotid arteries are clamped.
Control of the internal, external, and common carotid arteries is established
172
During a carotid endarterectomy, MAP plays the predominant role in determining CPP because?
ICP is usually not elevated
173
Opened artery exposes baroreceptors to atmospheric pressure leading to?
Causes firing down the myelinated A-type fibers and C-type fibers of the glossopharyngeal nerve to the nucleus tractus solitarius
Triggers central systemic pressure response
174
Carotid chemo-response
Rapid drop in oxygen tension
Further cause increasing signals down afferent pathway
175
Overall exposure of baroreceptors during CEA will cause
Onset of tachycardia and severe hypertension and thus increases in afterload and myocardial oxygen demand
176
GA does not prevent hemodynamic response of manipulation of the carotid sinus (severe vagal response) during CEA. The SRNA should know
Advisable to inject 1-2 mL of 1% lidocaine in the tissue b/w the internal and external carotid arteries before surgical manipulation (by surgeon)
Severe hemodynamic response can lead to spasming of the coronary artery
It is important to avoid large blood pressure swings especially upon intubation and emergence
177
Maintenance normocarbia during CEA, high or low will lead to?
Hypercarbia leads to cerebral vasodilation => Steal syndrome could occur.
Hypocarbia leads to vasoconstriction => Ischemia to compromised area(s) of brain
178
Two main intra-operative goals in CEA are?
Protecting the brain
| Protecting the heart
179
Protecting the heart is one of the main goals of CEA because?
The presence of concurrent CAD and carotid stenosis is well documented.
Although stroke is a devastating consequence of carotid endarterectomy, myocardial infarction contributes more frequently to poor surgical outcomes than stroke.
180
Perform a preoperative test on the effects of Operative Head Positioning on CBF because?
It is well documented that hyper-extension and lateral rotation of the head may occlude vertebral basilar flow and, if sustained, contribute to post-op cerebral ischemia.
181
In CEA, just before cross clamping of the carotid artery, an additional dose of Barbiturates, Benzo’s, Propofol, should be given for?
to produce burst suppression may be administered for its cerebral protective effects.
182
In a CEA patient, a hematoma that causes respiratory distress should be evacuated before re-intubation is attempted. T/F
True
183
If the CEA patient emerges from anesthesia with a new neurological deficit, what should be done?
immediate surgical exploration of the site or immediate cerebral angiography should be performed
184
Stump pressure (pressure distal to the carotid clamp) is used to evaluate the adequacy of cerebral perfusion. Cerebral ischemia rarely occurs at stump pressures of?
> 60 mmHg.
185
Traditionally a distal stump pressure of less ___________ has been used as an indication for a shunt
than 50 mm Hg
surgeon specific now
a
186
It is desirable to maintain MAP at or slightly above the patient’s highest recorded resting pressure while awake during CEA because?
Volatile anesthetics impair autoregulation; therefore, the higher the pressure, the more likely it is that cerebral perfusion will be adequate during surgical occlusion.
Phenylephrine is ideal to support BP
Maintain MAP (typical 80-100)
187
What is the appropriate regional block for CEA
Blockade of the superficial cervical plexus effectively blocks the C2-C4 nerves and allows the patient to remain comfortably awake during surgery.
188
What is the Principal advantage of regional block for CEA
Patients can be examined intraop thus the need for a temporary shunt can be assess and any new neurological deficits diagnosed immediately during surgery.
189
Nerves at risk of injury when the carotid sheath is opened to expose the carotid artery are
Phrenic
Vagus
Hypoglossal
RLN
190
ppoFEV1% =
=preop FEV1% x (1-% functional lung tissue removed)
__________________________
100
191
The three-legged stool of pre thoracotomy respiratory assessment
Respiratory Mechanics
ppoFEV1%
> 40% low risk
< 30% high risk
Lung Parenchymal Function (gas exchange)
DLCO
< 40% increased risk
Measures gas exchange capacity in the lungs.
Correlates with the functional surface area of the alveolar-capillary interface.
Cardiopulmonary Reserve (Cardio-respiratory interaction)
VO2max
< 15 mL/kg/min
Measures the maximum capacity of the body to transport and utilize oxygen during exercise
192
WHich of the heart chambers isn't ever implanted with pacer wire
Left atrium
193
Most modern pacemakers are?
Bipolar
194
Which types of cardiomyopathy may be an indication for pacemaker
Hypertrophic obstructive cardiomyopathy
Dilated cardiomyopathy
195
Troubleshooting a pacemaker requires?
Recognition of the problem
Knowledge of whether the device is magnet sensitive
Access to a programmer
196
Pacemaker capture
Depolarization of the heart chamber in response to PM electrical output
197
Failure to sense
The PM fails to recognize intrinsic cardiac electrical activity
198
Failure to capture
When PM's electrical output fails to cause myocardial depolarization
199
What are the Indications for Implantable Cardioverter defibrillators
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Coronary Artery Disease
Heart Failure
Arrhythmia
Structural Abnormalities
Conduction Disturbances
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200
Letters on AICD mean?
First letter describes the chamber that will be shocked
Second letter indicates the chamber where anti-tachycardia pacing occurs
Third letter denotes the device’s method of rhythm detection
Fourth letter identifies which chamber will deliver back-up pacing
201
Letters on pacemaker mean?
The first letter identifies the chamber where the pacing electrode is placed. (A,V,D)
The second letter identifies the chamber where the sensing electrode is placed. (A,V,D)
The third identifies the PMs response to the detection of spontaneous cardiac depolarization and its effect of subsequent pacing stimuli. (I,T,D)
The fourth letter of the code represents rate modulation (R, O)
The fifth and final letter identifies multisite pacing. (A,V,D,O)
202
12- lead ECG may reveal a paced rhythm but will not inform the provider of ?
the underlying rate dependence, or type of device.
203
To avoid harmful effects of EMI (Electromagnetic interference) on paced patients intraop
Reprogramming is recommended when expectation of increased EMI, cautery used, or when surgical site is close to device.
PM can be programmed to an asynchronous mode and an ICD can have anti-tachycardia therapy disabled.
204
Most prevalent source of EMI is
the electrosurgical cautery
205
Monopolar cautery produces more energy than bipolar and requires the placement of a grounding pad. Must make sure not to place where?
over implantable metal such as over total hip hardware
Less risk with bipolar electrocautery devices
206
________________ remains the only reliable method of CIED assessment.
Direct interrogation
207
The aortic systolic blood pressure results from the summated effects of
stroke volume
aortic compliance
peripheral vascular resistance.
208
The aortic wall has three layers, those are?
a thin intima or inner layer lined by endothelium,
a thick media or middle layer,
a thin adventitia or outermost layer.
209
The endothelium is the site for atherosclerosis because?
It is in direct contact with blood and it is easily traumatized.
210
The part of the aortic wall consists mainly of collagen and contains the vasa vasorum that nourishes the outer half of the aortic wall.
The adventitia
211
The frequency of infrarenal aortic aneurysms can be explained by?
The fact that the vasa vasorum are absent in the infrarenal aorta
212
The thoracic aorta comprises
the ascending aorta
the aortic arch
the descending aorta
213
The ascending aorta is about _______ cm long and comprises the_______ and ___________.
9 cm
aortic root and ascending aorta
214
Anatomy of Aorta
The aortic root includes the aortic valve annulus and the sinuses of Valsalva that terminate at the sinotubular junction.
The origin of the innominate artery marks the end of the ascending aorta and the beginning of the aortic arch.
The aortic arch lies within the superior mediastinum between the ascending and descending thoracic aorta.
215
The aortic isthmus is vulnerable to traumatic injury because?
It is subjected to high shear forces after blunt trauma or rapid deceleration.
216
The relatively mobile ascending aorta and arch join the descending thoracic aorta at?
Aortic isthmus
217
the most common site for aortic coarctation is?
Aortic isthmus
218
__________ are the first branches of the aorta.
The coronary arteries
219
The aortic arch subsequently gives origin to the ______________ arteries that supply the head, neck, and arms.
innominate
left carotid
left subclavian
220
The aortic arch also modulates blood pressure via __________ within its outer wall.
baroreceptors
221
The aortic bodies are located
inferior to the aortic arch.
222
The aortic baroreceptors are less sensitive when compared with the carotid sinus receptors because?
They respond to a greater threshold pressure
223
____________ can detect partial occlusion or obstruction of flow to innominate artery caused by inadvertent placement of aortic clamp too close to origin of innominate artery.
Right radial
224
Intraoperative TEE is reasonable in thoracic aortic procedures, including endovascular interventions, in which it assists in ?
hemodynamic monitoring, procedural guidance, and endoleak detection
225
Therefore, the detection of mobile atheroma in the aortic arch is an important TEE finding in TEVAR because?
it predicts a greater stroke risk.
226
TEVAR
Thoracic endoscopic aortic repair
227
In the presence of acute AR, β-blockers should be used with caution because
they block the compensatory tachycardia.
228
In the absence of contraindications in a patient with dissecting aorta, β-blockers should be titrated to a heart rate of
60 beats/min
229
In management of aortic disection, Vasodilator therapy should not be initiated before heart rate control because?
to avoid the associated reflex tachycardia that might
230
This class of intimal tear may occur at any aortic locus but is most common in the descending thoracic aorta.
Penetrating Atherosclerotic Ulcer which describes an isolated disruption of the intimal layer of the aortic wall at the site of atheromatous disease
231
Intraoperative epiaortic ultrasound imaging is superior to ____________ for thoracic aortic atheroma
manual palpation or TEE
232
chronic vasculitis that affects primarily the thoracic aorta
Takayasu arteritis
233
Takayasu arteritis occurs most frequently in
young Asian women and occurs worldwide.
234
______________ may be the only site for accurate measurement of central aortic pressure in patients with stenosis of both subclavian arteries
The femoral artery
235
In aortic coarctation, avoiding surgical dissection in the region of the distal aortic arch also decreases the risk for injury to the _____________ nerves.
recurrent laryngeal and phrenic
236
Spinal cord perfusion pressure=
mean arterial pressure – lumbar CSF pressure
SCPP=MAP-LCSFP
Should be > than 70 mm Hg after thoracic aortic repair
237
Potential complications of Lumbar Cerebral Spinal Drainage
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epidural hematoma
intradural hematoma
catheter fraction
meningitis
intracranial hypotension
& postdural puncture HA.
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