Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Lindsays Flashcardlet > RE4: Chapter 25: Anesthesia for Vascular Surgery > Flashcards

RE4: Chapter 25: Anesthesia for Vascular Surgery Flashcards

0
Q

What pharmacological therapy should be instituted in patients at high risk for myocardial ischemia and infarction days to weeks before surgery?

What range should the KR be kept?

A

B-blockers

HR should be between 50-60 bpm to decrease demand and increase supply

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
1
Q

What are major risk factors associated with atherosclerotic lesions???

A 
Hypercholesterolemia
Elevated triglycerides levels
Cigarette smoking
HTN
DM
Obesity
Genetic predisposition 
Sedentary lifestyle
Sex (male > female)
Impaired long-term glucose regulation
Homocysteine
C-reactive protein
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What is the primary objective in patients with vascular disease?

A

Detection of myocardial ischemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What do patients with HTN and/or angiopathology rely on to perfuse their vital organs?

A

Increased mean arterial pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Why is epidural opioids and local anesthetics in patients recovering from vascular surgery important postoperatively?

A

Pain can greatly enhance sympathetic nervous system stimulation

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are some risk factors associated with AAA?

A 
Smoking
Older age
Gender (male > female)
Family history
CAD
High cholesterol
COPD
Height (per 7cm interval)
HTN
Peripheral vascular occlusive disease
Caucasian
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Which risk factor is most highly correlated with AAA and how much does the incidence increase by?

A

Smoking

Incidence of AAA increases five-fold!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What size AAA is surgical intervention recommended for?

A

5.5cm or greater in diameter

<4cm have low risk of rupture, but risk dramatically increases for AAAs with a 5cm or greater diameter

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are contraindications to elective repair of AAA?

A

Intractable angina pectoris
Recent MI
Severe pulmonary dysfunction
Chronic renal insufficiency

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What calculation measures the wall tension of an aneurysm?

A

Law of Laplace

T = P x r

(As the radius increases, the wall tension increases. Therefore, the larger the aneurysm, the more likely the risk of spontaneous rupture.)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What is the average growth per year of an AAA?

A

4mm/yr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are the most important techniques used to enhance cardiac function during an AAA repair?

A

Preoperative fluidity loading and restoration of intravascular volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are the hallmark pharmacologic treatments for medical management of an AAA?

A

Beta blockers, statins, and aspirin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What monitors should be used for AAA?

A 
ECG with lead II for detection of dysrhythmias and V5 for analysis of ischemic ST-segment changes
Pulse ox
Capnography
Esophageal stethoscope
Urinary catheter
Invasive BP monitoring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the primary method of intraoperative cardiac assessment?

A

TEE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

True or False. Wall motion abnormalities occur sooner than ECG changes during periods of reduced coronary blood flow.

A

TRUE

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Where is the most common site for cross-clamping for AAA?

A

INFRARENAL - because most aneurysms appear below the level of the renal arteries

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What happens to the BP above the clamp and below the clamp during the cross clamping of the aorta?

A

Hypertension ABOVE the cross-clamp

Hypotension BELOW the cross-clamp

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What happens to the MAP and SVR with cross-clamping?

A

Increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What happens to CO with cross clamping?

A

Decrease or remain unchanged

PAOP may increase or display no change as well

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What may the increased wall stress from increased afterload with cross clamping contribute to?

A

Decreased global ventricular fxn and myocardial ischemia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What happens metabolically to the tissues distal to the cross-clamp?

A

Prone to developing hypoxia. In response to hypoxia, metabolites such as lactate accumulate.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is released that may also contribute to cardiac instability during aortic cross-clamping?

What can be administered to pretreat this?

A

Arachidonic acid derivatives
Thromboxane A2 synthesis may be responsible for decreasing myocardial contractility and CO

ASA or ibuprofen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What can mesenteric traction cause during AAA?

What metabolite is associated with this?

A

Mesenteric traction syndrome - decreases in BP and SVR, tachycardia, increased CO, and facial flushing

6-ketoprostaglandin F1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

What neuroendocrine response/mediators are release in response to surgical stress?

What do they cause?

A

Cytokines such as interleukin (IL)-1B, IL-6 and tumor necrosis factor as well as plasma catecholamines and cortisol.

They trigger an inflammatory response that results in increased body temp, leukocytosis, tachycardia, tachypnea and fluid sequestration.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

What is one of the most significant predictors of postop renal dysfunction?

A

Preoperative evaluation of renal function!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

What is associated with spinal cord damage with aortic occlusion?

A

Interruption of blood flow to the greater radicular artery (artery of Adamkiewicz) in the absense of collateral flow may cause paraplegia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

What can identify spinal cord ischemia intraoperative?

A

SSEPs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

What do SSEPs reflect and what does it NOT provide information about?

A

SSEPs reflect dorsal (sensory) spinal cord function and doesn’t provide information regarding the integrity of the anterior (motor) spinal cord.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

What is capable of determining anterior (motor) cord function?

A

MEPs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

What is attributed to the manipulation of the inferior mesenteric artery?

A

Ischemia of the colon b/c the inferior mesenteric artery is the primary blood supply to the left colon.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

While the aorta is occluded, what metabolites are released d/t anaerobic metabolism?

What does this cause?

A

Metabolites such as lactate accumulate below the clamp inducing vasodilation and vasomotor paralysis.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

As the cross clamp is released, SVR decreases and blood is sequestered into the previously dilated veins which decreases venous return. What does this cause?

A

Reactive hypermedia causes transient vasodilation secondary to presence of tissue hypoxia, release of adenine nucleotides and liberation of a vasodepressor substance that acts as a myocardial depressant and peripheral vasodilator. This causes DECREASED PRELOAD AND AFTERLOAD!!!

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What is the hemodynamic instability that may ensue after the release of an aortic cross-clamp called?

What does this cause?

A

Declamping shock syndrome

Severe hypotension and reduction in CO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

How can declamping shock syndrome be prevented?

A

Volume loading just before the clamp is released

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

What is paramount in providing circulatory stability before release of the aortic clamp?

A

Restoration of circulating volume

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q 
What are the consequences of the following with aortic declamping?
MAP
Contractility
SVR
CVP
Preload
CO
PA pressures
A

Everything decreases except PA pressures

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

As the aorta is clamped more proximally, what happens to the LV afterload and what is more likely to occur?

A

Afterload increases and myocardial ischemia is more likely to occur

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

What surgical action results in less severe hypotension?

A

Partial release of the aortic cross-clamp over time

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

What are the two surgical approaches for an elective AAA reconstruction?

Advantages vs. Disadvantages

A
  1. Transperitoneal incision
    Advantages: familiarity, exposure of infrarenal and iliac vessels, ability to inspect intraabdominal organs, rapid closure, and versatility
    Disadvantages: increased fluid loss, prolonged ileus, postoperative incisional pain, and pulmonary complications
  2. Retroperitoneal incision
    Advantages: excellent exposure (esp. for juxtarenal and suprarenal aneurysms and in obese Pts), decreased fluid losses, less incisional pain and fewer postoperative pulmonary and intestinal complications
    Disadvantages: unfamiliarity, poor right distal renal artery exposure, and inability to inspect the integrity of the abdominal contents
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

True or False. CAD exists in more than 50% of patients who require abdominal aortic reconstruction and is the single most significant risk factor influencing long-term survival.

A

True

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Who should high concentrations of VAs not be used with during AAA and why?

A

Pts with moderate to severe decreased EF d/t depression of myocardium and hemodynamic instability caused by VAs

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

What are the benefits of epidurals used with AAA?

A 
Decreased preload and afterload
Preserved myocardial oxygenation
Reduced stress response 
Excellent muscle relaxation
Decreased incidence of postop thromboembolism
Increased graft flow to lower extremities
Decreased pulmonary complications
Improved analgesia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

What is an largely unfavorable result of epidurals?

A

HYPOTENSION during blood loss or declamping

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

What rate is crystalloid used for replacing basal and third space losses?

A

10mL/kg/hr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

What ratio can blood loss be replaced by crystalloids?

A

3:1

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

What rate should UO be maintained intraoperatively?

A

1ml/kg/hr

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

What induction agent is most suitable for pts with limited cardiac reserve?

A

Etomidate

Slow induction with opioids and b-blockers can preserve hemodynamic stability

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
48
Q

What is the difference between juxtarenal and suprarenal aortic aneurysms?

A

Juxtarenal aneurysms are located at the level of the renal artery, but spare the renal artery orifice. Whereas most proximal suprarenal aneurysms include at least one of the renal arteries and may involve visceral vessels.

49
Q

When does renal failure occur more frequently, infrarenal or suprarenal aortic occlusion?

A

Suprarenal

50
Q

What are some interventions that may minimize renal ischemia and dysfunction?

A

Maintaining adequate intravascular VoLTE and administrating osmotic and loop diuretics

51
Q

True or False. Paraplegia is possible when the blood supply to the spinal cord is interrupted by aortic cross clamp at or below the level of the diaphragm.

A

FALSE. At or ABOVE the level of the diaphragm

52
Q

What may be used as a means to increase spinal cord perfusion pressure?

A

Increasing MAP or decreasing CSF by placing a catheter in the subarachnoid space to drain CSF

53
Q

What is imperative to maintain postoperatively in AAA pts?

A

Adequate BP, intravascular fluid volume, and myocardial oxygenation

54
Q

What are common symptoms of ruptured AAA?

A

Abdominal discomfort or back pain
Hypotension
Pulsatile mass

55
Q

What is the primary focus with a ruptured AAA?

A

Cardiovascular stability

56
Q

What are aneurysms called that involve all three layers of the arterial wall?

What are the 3 layers called?

A

True aneurysm

  1. Tunica adventitia
  2. Tunica media
  3. Tunica intima
57
Q

What are aneurysms called that solely involve the adventitia?

A

False aneurysms

58
Q

What are aneurysms called that have spindle shape and result in the dilation of the aorta?

A

Fusiform aneurysm

59
Q

What aneurysms are spherical dilations and generally are limited to only one segment of the vessel wall?

A

Saccular aneurysms

60
Q

What is an aortic dissection the result of?

A

Spontaneous tear with the intima that permits the flow of blood through a false passage along the longitudinal axis of the aorta.

61
Q

What are some symptoms of a thoracic aneurysm?

A

Pain, strider and cough due to compression of thoracic structures.

62
Q

What types of aneurysms necessitates the use of CPB?

A

Resection of the ascending aorta and graft replacement

63
Q

What does surgical resection of lesions in the transverse arch compromise?

What techniques help decrease this?

A

Cerebral perfusion

Profound hypothermia and circulatory arrest

64
Q

What is the most common factor that contributes to the progression of the lesion of an aortic dissection?

A

HTN

65
Q

Which type of lesions have the highest incidence of rupture and require immediate surgical intervention?

A

Type A - dissections that involves the ascending aorta

66
Q

Which lesion may initially be managed medically with administration of arterial dilating and beta-blockers?

A

Type B - dissections that do not involve the ascending aorta

67
Q

Aneurysms located where require CPB?

A

Ascending and transverse aorta

68
Q

What should be carefully assessed preoperatively before a AA repair?

A

Renal function
Neuro function esp lower extremity function
Left RLN due to close proximity to aortic arch

69
Q

What types of monitoring is recommended with thoracoabdominal aneurysms?

A

Arterial line and PAP with CPB!
(If aneurysm involves the thoracic region of the distal aortic arch, the RIGHT radial artery is preferred b/c of left subclavian arterial blood flow may be compromised with surgery.)

DLTs, lumbar intrathecal catheter to access CSF, SSEPs and MEPs

70
Q

What is the most effective means of decreasing afterload during cross-clamp application?

A

Sodium nitroprusside

71
Q

What may be given during aortic occlusion to decrease preload?

A

Nitroglycerin

72
Q

Where does the artery of Adamkiewicz (greater radicular artery) originate from?

A

Intercostal branch b/w T8 and L2 and provides majority of blood flow to the ANTERIOR SPINAL ARTERY. This artery perfuses the VENTRAL aspect of the spinal cord, which is responsible for motor control.

73
Q

What is vital to avoid spinal cord deficits?

A

Avoiding prolonged periods of hypotension

74
Q

How can spinal cord perfusion be measured?

A

arterial BP - CSP pressure

75
Q

What factors contribute to the development of neurological deficit with aortic cross clamping?

A

Level of aortic clamp application
Ischemic time
Embolization or thrombosis of a critical intercostal artery
Failure to revascularize intercostal arteries
Urgency of surgical intervention

76
Q

What types of aneurysm can endovascular aortic aneurysm repair be performed on?

A

Descending thoracic aortic aneurysm and AAAs

77
Q

What heparin dose is administered prior to catheter manipulation for endovascular aortic aneurysm repair?

A

50-100 units/kg

78
Q

What are the goals for intraoperative management for EVAR?

A

Maintain hemodynamic stability
Provide analgesia and anxiolysis
Be prepared to convert to an open procedure

79
Q

What is an Endoleak?

Which type is the most common?

A

persistent blood flow and pressure (endotension) between the endovascular graft and the aortic aneurysm

Most common are type II and 70% spontaneously close within the 1st month after implantation. Type II endoleaks are caused by collateral retrograde perfusion.

80
Q

The increased risk of ________ associated with ___ provides the rationale for the use of carotid endarterectomy (CEAs)

A

Stroke associated with TIA

81
Q

Carotid artery stenosis is the primary cause of approximately ____% of all strokes.

A

20%

82
Q

Patients with carotid stenosis greater than ______%, have the greatest benefit from a CEA.

A

70%

83
Q

What was found to the most significant factor for predicting postoperative stroke incidence?

A

Preoperative neurologic dysfunction

84
Q

What syndrome occurs in 25% of patients with high grade carotid artery stenosis?

A

Amaurosis fugax or monocular blindness (caused by microthrombi that travel into the internal carotid and decreases the blood supply to optic nerve via ophthalmic artery)

85
Q

How is cerebral perfusion pressure calculated?

A

CPP = MAP - ICP

**MAP plays the predominant role in determining CPP

86
Q

At what MAPs does CPF remain constant?

A

Between 60 and 160mmHg

87
Q

How does chronic systemic HTN affect CBF?

A

It shifts the curve to the right, therefore a higher than normal MAP may be required to ensure adequate cerebral perfusion

88
Q

What is normal CBF?

A

50mL/100g/min

89
Q

At what CBF rate is neural function generally maintained at?

A

> 25mL/100g/min

90
Q

At what CBF does cellular death occur?

A

< 6mL/100g/min as evidenced by flattening seen on the an electroencephalogram

91
Q

Why is normocapnia paramount?

A

Hypocapnia decreases and hypercapnia increases CBF

92
Q

What is the most sensitive and specific measure of adequate cerebral blood flow?

A

An awake patient

93
Q

What are the major objectives during carotid artery revascularization?

A

Maintain CBF and decrease cerebral ischemia

94
Q

What is the gold standard in identifying neurologic deficits related to carotid artery cross-clamping?

A

Electroencephalographic monitoring

95
Q

What on the EEG are indicative of neurologic dysfunction?

A

Loss of B-waves, loss of amplitude and emergence of slow wave activity.

96
Q

What carotid stump pressure reflects neurologic hypoperfusion and a criterion for shunt placement?

A

< 40-50mmHg

97
Q

Can a motor deficit occur despite a normal SSEP waveform?

A

Yes b/c SSEPs are only measuring the integrity of the dorsal or sensory portion of the spinal cord.

98
Q

With cerebral oximetry, a reduction of critical oxygen saturation during clamping of greater than ___ or ____% if persistent for longer than ___ minutes indicates the potential for deficits.

A

20-25%

4 minutes

99
Q

What measurements and intraoperative monitoring modalities are used to determine the need for shunt placement during CEAs?

A

Stump pressure and EEG

100
Q

How is prevention of cerebral ischemia accomplished?

A

Increasing collateral flow (placement of intraluminal shunt) or decreasing cerebral metabolic requirements (pharmacological adjuncts)

101
Q

What does the application of the intraluminal shunt pose the risk of?

A

Embolic complications and intimal dissections

102
Q

Anesthetics except for which drug have cerebral protective properties.

A

Etomidate

103
Q

The surgeon may request which two drugs to be administered before the carotid artery is cross-clamped for cerebral protection?

A

Propofol or Precedex

104
Q

What is hypotension and hypertension related to with CEAs?

A

Hypotension - result of carotid sinus baroreceptor stimulation

Hypertension - surgical manipulation of the carotid sinus

105
Q

What pharmacologic adjuncts should be used for BP control with CEAs?

A

(ALL patients should continue BP medications until the time of surgery!)

Short acting beta-blockers may stabilize BP during induction/emergence

Nitroglycerin and sodium nitroprusside should be available to treat HTN

106
Q

What are the anesthetic goals specific to CEAs?

A

Maintain cerebral and myocardial perfusion and oxygenation
Minimize the stress response
Facilitate a smooth and rapid emergence

107
Q

What regional technique can be used for CEA?

What is the advantage?

A

Superficial and deep cervical plexus block (CN II to IV)

Allows the ability to directly assess neurologic function in an awake patient.

108
Q

What is the limiting factor for the use of a regional technique?

A

Patient acceptance

109
Q

What are the advantages of GA with CEA?

A

Motionless surgical field
Inhalation agents provide hemodynamic stability and beneficial effects on cerebral circulation (provides a degree of protection against ischemia)

110
Q

What is the degree of protection against ischemia that VAs provide called?

A

Anesthetic preconditioning

111
Q

With carotid artery cross-clamping without shunting occurs, where should the MAPS be?

A

MAP values should approximate or be slightly above preoperative levels to ensure adequate cerebral perfusion through the contralateral carotid artery.

112
Q

What is the most common postoperative problem with CEAs?

A

HTN

113
Q

What systolic BP is associated with an increased incidence of TIA, stroke or MI?

A

SBP > 180mmHg

114
Q

What is an uncommon, but very serious complication of a CEA?

A

Carotid artery hemorrhage

115
Q

What are initial manifestations of carotid artery hemorrhage?

A

Upper airway obstruction - reintubation difficult or impossible b/c of tracheal deviation
RLN damage
Tension pneumothorax
Cerebral hyper perfusion syndrome (CHS)

116
Q

What is cerebral hyper perfusion syndrome (CHS)?

A

Damage to the carotid body leading to blunting of the chemoreceptor reflex and O2 should be given. It results from increased blood flow to the brain as a result of loss of cerebral vascular autoregulation.

117
Q

What are s/s of CHS?

A

Severe HA
Visual disturbances
Altered LOC
Seizures

118
Q

What anesthetic technique is most often used with carotid artery angioplasty stenting (CAS)?

A

Local anesthesia at the femoral insertion site and minimal sedation

119
Q

What is the heparin dose for CAS?

A

50 - 100unit/kg to maintain an ACT > 250 seconds

120
Q

What can cause prolonged bradycardia and hypotension with balloon inflation in the internal carotid artery with CAS?

What drugs are commonly used to treat this?

A

Stimulation of the baroreceptor response

Robinal or atropine given prior to balloon inflation

121
Q

What is the most common complication of CAS?

A

Stroke cause by thromboembolism

Lindsays Flashcardlet (27 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions