Anesthesia for Cardiothoracic Procedures Flashcards
1
Q
Surgical approaches in cardiac surgery
A
- Open heart surgery (sternotomy or thoracotomy)
- Davinci robotic
- Endovascular (valve repair/aortic repair)
2
Q
Invasive technique
A
Open sternotomy technique
3
Q
Cardiac surgery technique with most possible complications
A
Invasive
4
Q
Best exposure for cardiac surgery techniques
A
Invasive
5
Q
Minimally invasive techniques
A
- Thoracotomy approach
- Davinci Robotic approach
- Endovascular
6
Q
Less common cardiac surgery techniques
A
Minimally invasive
7
Q
Implications of minimally invasive surgeries
A
- One lung may need deflated, so a double lumen tube is needed
- Can be performed off pump, or use bypass through femoral vessels
8
Q
Common aortic repair surgery
A
Endovascular
9
Q
Surgical options for CABG
A
- Full bypass with arrested or beating heart
- Partial bypass with a beating heart
- Off pump
- Sternotomy
- Thoracotomy
- Davinci
10
Q
How is a MICS CABG done?
A
- Small thoracotomy incision
2. Most commonly performed off pump
11
Q
What is MICS CABG reserved for?
A
1 or 2 vessel disease since exposure is limited to the anterior vessels
12
Q
What is the Davinci used for in CABG?
A
To harvest LIMA
13
Q
How is the graft sewn in Davinci CABG?
A
Through a small, anterior thoracotomy incision
14
Q
What is hybrid coronary revascularization?
A
Anterior vessels are bypassed with MICS/thoracotomy approach by cardio and more difficult to expose vessels are stented by IR without sternotomy
15
Q
What are hybrid rooms used for?
A
- Hybrid coronary revasularization
2. Transcatheter aortic valve replacement (TAVR)/Transcatheter aortic valve implantation (TAVI)
16
Q
What was shown to be superior to intravascular stent placement?
A
LIMA to LAD graft without sternotomy
17
Q
Premedication for CABG
A
Avoid anxiety and tachycardia for CAD, heavier medication than valve replacement
18
Q
Surgical options for valve repair/replacement
A
- Full bypass with an arrested or beating heart
- Right Heart bypass
- Endovascular or transapical valve replacement (both off pump)
- Sternotomy
- Thoracotomy
- Davinci
19
Q
How are stenotic heart valves fixed?
A
- Most commonly replaced for better outcomes
2. Can remove calcifications
20
Q
How are regurgitant valves fixed?
A
Repaired or replaced
21
Q
Premedication for valve repair/replacement
A
Causes hypotension and vasodilation, which reduces preload and afterload. Need to maintain preload and afterload, so try to avoid premedication
22
Q
Is valve repair/replacement with MICS commonly performed on or off pump?
A
On pump with bypass cannulation in the femoral vessels
23
Q
When is endovascular valve repair an option?
A
For patients who may not qualify for open heart surgery
24
Q
When are patients considered at too high of a risk for heart surgery?
A
30-40% of patients with aortic stenosis
25
Other names for endovascular aortic valve replacement
TAVR or TAVI
26
Possible catheter/stent pathways for TAVR/TAVI
1. Femoral artery to aortic valve (most common)
| 2. Axillary artery to aortic valve
27
Catheter/stent pathway for mitral valve repair
Femoral vein to intra-atrial septum to mitral valve
28
Catheter/stent pathway for tricuspid and pulmonary valves
Femoral vein and passing through R side of the heart
29
Valve replacement being performed "off pump" with an "open" approach
Transapical valve replacement
30
Risks associated with endovascular TAVR
1. Stroke & TIA
2. Perivalvular leak
3. Vascular complications (perforation, dissection and/or rupture)
4. AKI (due to contrast used)
5. Cardiac conduction abnormalities (LBBB)
6. Postop bleeding and afib
31
Does TAVR or surgical replacement have a higher risk of stroke?
TAVR
32
Which valve has a higher risk of a leak after repair/replacement?
Aortic regurg
33
Most frequent adverse outcome associated with TAVR
Vascular complications
34
How can vascular complications be limited with TAVR?
By using transapical thoracotomy
35
Anesthetic management for endovascular TAVR (10)
1. Renal protection
2. Stroke prevention
3. Lower dose of heparin
4. Placement of transvenous pacing leads
5. Attaching of external defibrillator pads
6. TEE
7. No Amicar
8. Keep heart still
9. Hemodynamic goals
10. Continuous post op EKG for 48 hrs
36
Renal protection for endovascular TAVR
1. Adequate perioperative volume loading
| 2. Administration of N-acetylcysteine prior to surgery
37
Stroke prevention for TAVR
Dual antiplatelet therapy started before the procedure and continued for 6 months (loading dose of 300mg-325mg ASA and 300 mg Plavix prior to procedure)
38
Goal ACT for endovascular TAVR
>250s
39
How do you keep the heart still during valve deployment for TAVR?
1. RVP (rapid ventricular pacing) with rate of 180-220 bpm
| 2. Virtually stopping heart with adenosine
40
Should you be concerned with hypotension when keeping the heart still during TAVR?
No, valve deployment is quick and rebound hypertension can exacerbate valvular regurge
41
Hemodynamic goals for patients with aortic stenosis
1. Preload augmentation (inc)
2. Low HR (50-70 bpm)
3. Maintain sinus rhythm
42
When is a temporary pacemaker left after TAVR?
In all patients with AV block
43
Management for endovascular aorta surgery
1. No sternotomy/bypass
2. Less heparin
3. No Amicar
44
Techniques for aortic root replacement
Traditional bypass with arrested heart bc clamp can be placed on ascending aorta
45
Surgical techniques for open ascending aorta repair
1. Traditional bypass w/o circ arrest if clamp can be placed on ascending aorta
2. DHCA or normothermic antegrade cerebral perfusion if aneurysm extends into aortic arch
46
Problem with open descending aorta repair
Not possible to perfuse both head and lower extremities with one arterial cannula
47
Open ascending aorta repair options
1. Partial cardiopulmonary bypass
2. Left heart partial bypass
3. Circ arrest
48
Increases the chance of paralysis from inadequate spinal cord perfusion
Clamps on descending aorta
49
Oxygenator must be used with this technique
Descending aorta repair with partial CPB
50
Anesthetic considerations for left heart bypass
1. Requires intensive vigilance to hemodynamics by both the anesthesiologist and the perfusionist
2. Arterial pressure should be measured in the R radial artery and femoral artery to assess pressure distal to the clamp
3. CVP should be compared to PA diastolic or wedge pressure to assess filling of the two ventricles
51
What happens if pressure is too high proximally and low low distally in L heart bypass?
Flow is increased through the circuit
52
What happens if both pressures are too low in L heart bypass?
Fluids or vasoconstrictors should be considered
53
What happens if both pressures are too high in L heart bypass?
A vasodilator should be considered
54
Anesthetic management for open descending aorta repair
1. Place A-line in R arm
2. Insert double lumen tube
3. Prepare standard cardiac drugs
4. Consider techniques for spinal cord protection
55
Why is the A-line placed in the R arm for open descending aorta repair?
Clamping proximal to L subclavian artery may be necessary
56
Why insert a double lumen tube for open descending aorta repair?
A thoracotomy approach will most likely be used
57
Possible spinal cord protection techniques for open descending aorta repair
1. SSEP/MEP monitoring
2. Lumbar drain (inc spinal cord perfusion pressure)
3. Steroids (dec swelling)
4. Mannitol (inc spinal cord perfusion through dec CSF production and improves renal perfusion)
58
Spinal cord perfusion pressure equation
Spinal cord PP = MAP-CSF pressure
59
Open chest procedure to treat aortic aneurysm
Aortic wrapping procedure
60
Heart transplant classifications
1. Orthotopic
| 2. Heterotopic
61
What is an orthotopic heart transplant?
1. Replacing the recipient heart with the donor heart
| 2. Biatrial, bicaval, total heart transplant
62
What is a heterotopic heart transplant?
The donor heart is placed in the R chest alongside the recipient organ and anastomosed to allow blood to pass through either or both hearts
63
What is biatrial heart transplant?
1. Only the ventricles are removed
| 2. Donor heart attaches to original at the midatrial level
64
How many anastomosis' does a biatrial transplant require?
4
1. Aorta
2. Pulmonary artery
3. Left atrium
4. R atrium
65
What is a bicaval heart transplant?
1. The entire R atrium is removed
| 2. Anastomosis' at SVC and IVC instead of atrial level
66
Number of anastomosis with bicaval heart transplant
5
1. Aorta
2. Pulmonary artery
3. L atrium
4. SVC
5. IVC
67
What is a total heart transplant?
Removal of all heart, including L atrium
68
How many anastomosis does the total heart transplant require?
6
1. Aorta
2. Pulmonary artery
3. Pulmonary veins x2
4. SVC
5. IVC
69
Advantages of the biatrial technique
1. Shorter operation times
| 2. Less anastomotic complications
70
Risk of biatrial technique
1. Post op atrial arrhythmias
2. Atrial enlargement
3. Atrial thrombi
4. Tricuspid valve regurge
71
The more heart you remove, the (better/worse) post op function, but the operation times will be (shorter/longer)
Better post op function, longer operation times
72
Releases Ach to bind to muscarinic receptors on the SA node
Presynaptic vagus nerve
73
Can atropine and robinul increase HR in patients that have had a heart transplant?
Only after Neostigmine is given due to the increased release of Ach
74
What patients have a stronger right ventricle?
Patients with pulmonary hypertension
75
Patients with heart failure are more likely to develop:
pulmonary hypertension and R ventricular hypertrophy
76
What is the problem with pulmonary hypertension and heart transplants?
The pt still has high pulmonary vascular resistance, but now has a normal sized R ventricle that cannot pump against the high PVR, causing post-transplant R heart failure
77
What is a transplant option for patients with severe pulmonary hypertension or CHF?
Heterotopic heart transplant
- old heart pumps blood to lungs (R vent)
- new heart pumps blood to body (L vent)
- Over time, pulmonary HTN will resolve
78
Implications of denervation
1. Resting HR is usually faster (>90bpm)
2. Atropine and Robinul (alone) have little to no effect on HR
3. Neostigmine causes bradycardia, which can be treated with anticholinergics
4. Bradycardia must be treated with pacing or with beta 1 agonists
5. Pt cannot experience angina
6. Baroreceptor reflex doesn't work, so HR may not respond to changes in BP
7. Sympathetic "reinnveration" can occur within 12 mos of operation
8. Inc of CO following exertion is primarily due to an increase in SV
9. If biatrial technique is used, the SA node of the donor controls HR and 2 P waves will be produced
79
Anesthetic management for heart transplant procedure
1. PA pressure should be kept low to prevent R heart failure
2. Inotropic support is more likely to be needed than for other cardiac operations
3. Immunosuppressive therapy should be implemented
4. Beware of hyperkalemia post transplant
80
Strategies to reduce pulmonary artery pressure
1. Hyperventilation
2. Higher FiO2
3. Pulm vasodilators (nitrates, prostaglandin, NO)
4. Avoidance of acidosis
81
Where are venous cannulas placed for heart transplants?
In SVC and IVC
82
What does Transmyocardial Revascularization (TMR) do?
-Laser creates holes in the myocardium to relieve angina in patients not eligible for bypass or angioplasty
83
Why would a patient not be eligible for bypass or angioplasty?
Small vessel CAD or no available grafts
84
2 theories for TMR's efficacy
1. Stimulates angiogenesis (new channels for blood flow)
| 2. Destroys nerve endings
85
Anesthetic considerations for TMR
1. Has been used in combo with CABG
2. Use of a double lumen tube and L lung isolation is required when performed by itself due to L anterior thoracotomy
3. Arrhythmias and decrease in CO can be expected, antiarrhythmic prophylaxis should be considered and vasopressors & inotropes should be available
86
-Fluid around the heart or fluid accumulation in the pericardial cavity
Pericardial effusion
87
When a pericardial effusion gets large enough to adversely effect heart function (low EF)
Cardiac tamponade
88
At induction of anesthesia, cardiac tamponade patients are at risk for ____
Severe hypotension and cardiac arrest
89
Hemodynamic effects of cardiac tamponade
1. Decreased CO (dec SV)
2. Beck's triad: hypotension, JVD, muffled heart tones
3. Pulsus paradoxus
90
Treatments for cardiac tamponade
1. Pericardiocentesis
| 2. Pericardial window
91
GETA is more likely with (pericardiocentesis or pericardial window)
Pericardial window, more invasive
92
Anesthetic management for pericardial window
1. General vs MAC
2. Impending tamponade? Is this an emergency?
3. Induction in unstable patients: head of bed elevated 45 degrees, use ketamine or etomidate, wait for surgeon to be ready prior to induction
4. Avoid bradycardia
5. Maintain spontaneous ventilation
93
If the patient is stable, which approach to pericardial window can be used?
Thoracotomy
94
If an emergency, which approach to pericardial window is used?
Subxiphoid (can be done under local and sedation)
95
How do you induce anesthesia for unstable pericardial windows?
1. Elevate head of bed 45 degrees to decrease dyspnea
2. Avoid propofol, use ketamine or etomidate
3. Surgeon scrubbed and dressed prior to induction
96
When is CO more dependent on HR?
In pediatric patients and cardiac tamponade patients
97
Why should spontaneous ventilation be maintained during pericardial window?
Positive pressure ventilation decreases venous return and CO
98
What is a mediastinoscopy done for?
-Obtaining a biopsy to rule out types of cancer
99
What can happen during mediastinoscopy?
The scope can compress the innominate (brachiocephalic) artery
100
What does the innominate artery supply?
R arm and R carotid artery
101
Why is it concerning for innominate artery compression?
If a pt has L carotid stenosis, they are at risk for cerebral ischemia
102
Anesthetic management for mediastinoscopy
1. Single lumen ETT
2. A-line in R arm
3. SpO2 on R
103
Primary concern with a mediastinal mass?
Compression of the heart, central blood vessels, trachea and bronchi
104
Symptoms of compression of heart, central vessels or venous return from SVC
1. Decreased CO and potential CV collapse
2. Airway edema and potential difficult airway management
3. increased ICP
105
Most common cause of SVC syndrome
Malignancy
106
What is SVC syndrome?
When a patient shows signs of SVC obstruction from a mediastinal mass
-airway and facial edema, decreased CO, increased ICP
107
What is Pemberton's sign?
- Facial congestion, cyanosis and possibly respiratory distress after raising both arms in the air for approximately one minute
- Caused by venous obstruction from goiters or mediastinal masses
108
True/false: Spontaneous ventilation is better for maintaining airway patency than control ventilation
True
109
Where should you aim to intubate with a tracheobronchial obstruction?
Distal to the obstruction
110
What is necessary if you cannot intubate distal to the tracheobronchial obstruction?
-Surgical intervention of tracheal or bronchial stenting with the aid of bronchoscopy and/or jet ventilation
111
Uses high pressure, provides way for pt to be ventilated through a small catheter
Jet ventilation
112
Anesthetic management for mediastinal mass (10)
1. Order and review diagnostic tests (CT, CXR, ECHO, PFTs)
2. Maintain spontaneous ventilation if possible
3. Perform an awake fiberoptic intubation in the sitting position if possible if pt is symptomatic
4. Consider using an "armored" ETT
5. Avoid hypotension and CV collapse if not doing an awake intubation by doing inhalational induction or routine induction
6. Have plan for ventilation based on where the obstruction is and how significant it is
7. Use semi-upright position for induction and maintenance
8. Avoid hypotension to maintain cerebral perfusion pressure
9. Place IVs in lower extremities if evidence of SVC syndrome, consider preload augmentations
10. Consider need for immediate surgical intervention in case of sudden airway or CV collapse
113
Associated with significant risks of complications from GA in mediastinal masses
2 or more significant abnormal findings in CT, spirometry or ECHO
114
What is laser lead extraction used for?
If pacing leads get infected and need to be removed, they are guided over wires to remove tissue surrounding the leads
115
What can happen during laser lead extraction?
Abrupt, severe onset of hypotension and hemorrhage
