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AS - N934 Advanced Principles II > Vascular > Flashcards

Vascular Flashcards

1
Q

Atherosclerosis

Stage I

A

Fatty streak

  • Endothelium damaged d/t hemodynamic shear stress, oxidize LDL destruction, chronic inflammatory responses, infection, & hypercoagulability → thrombosis
  • Lipoproteins enter the arterial intimal layer via endothelium, become entrapped, & promote inflammation
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2
Q

Atherosclerosis

Stage II

A

Fibrous plaque

  • Oxidized lipid accumulation, inflammatory cells, proliferated smooth muscle cells, connective tissue fibers, & Ca2+ deposits
  • Blood flow reduction → ischemia to vital organs & extremities → thrombus risk
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3
Q

Atherosclerosis

Stage III

A

Advanced lesion

  • Plaque w/ expanded lipid-rich necrotic core, Ca2+ accumulation, endothelial dysfunction
  • Physical disruption to plaque protective cap (ulceration rupture) exposes blood to highly thrombogenic material promoting acute thrombus formation & vasospasm
  • Complete occlusion possible → MI, stroke, ischemia
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4
Q

Atherosclerosis Pathophysiology

A

Generalized, progressive, chronic inflammatory disorder
Fibrous intimal plaques associated w/ endothelial dysfunction develop in the arterial tree
Compromises blood flow to all organs & extremities lead to MI, stroke, & gangreneA

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5
Q

Atherosclerosis Types

A
  1. Enlarged plaque reduces blood vessel lumen (ischemia or stable angina) → supply vs. demand & delayed periop MI
  2. Plaque rupture/ulceration, embolization, & thrombus formation (unstable angina, MI, TIA/CVA) → acute occlusion & early periop MI
  3. Media atrophy w/ arterial wall weakening (aneurysm dilation)
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6
Q

What’s the most common site for atherosclerotic lesions?

A 
42% aortoiliac peripheral
32% coronary
17% aortic arch branches
6% combined
3% mesenteric renal
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7
Q

What medications to continue prior to vascular surgery?

A 
Aspirin - antiplatelet ↑bleeding ↓GFR
Statins - check liver function
Diuretics - hypovolemia & electrolyte imbalance
Ca2+ channel blockers - HoTN
β blockers - bronchospasm ↓HR ↓BP
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8
Q

What medications to discontinue prior to vascular surgery?

A

ACE inhibitors - HoTN w/ induction & coughing
Plavix (hold 7-8 days) antiplatelet ↑bleeding risk
Hypoglycemic drugs - hypoglycemia & lactic acidosis w/ Metformin

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9
Q

Bare Metal Stent

A

Do NOT stop antiplatelet therapy < 1mos

↑MI risk

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10
Q

Drug-Eluting Stent

A

Do NOT stop antiplatelet therapy < 6mos

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11
Q

What’s the critical period for coronary stents to endothelialize?

A

6 weeks

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12
Q

Recommendations to optimize patient prior to vascular surgery:

A

Smoking cessation

Weight loss & exercise

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13
Q

Culprit Lesions

A

Vulnerable plaques w/ high thrombotic complication likelihood
Often located in coronary vessels w/o critical stenosis

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14
Q

Demand Ischemia

A

Predominant cause periop MI

Supply/demand mismatch

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15
Q

What predicts long-term mortality associated w/ vascular surgery?

A

Preop renal insufficiency or chronic renal disease → postop failure

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16
Q

LE Peripheral Artery Disease

A

PAD or atherosclerotic occlusive LE disease

Insufficiency in LEs presenting w/ acute or chronic limb ischemia w/ occlusions distal to the inguinal ligament

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17
Q

LE Peripheral Artery Disease Revascularization Associated Risks

A

Amputation, stroke, MI, death
Diabetes ↑risk

Assume atherosclerosis present in other areas - cardiac or cerebrovascular

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18
Q

LE Peripheral Artery Disease

Revascularization Preop Considerations

A

Patients on antiplatelet & anticoagulants
- Ask when last taken
- Consult w/ surgical team about bleeding risk
- ASA, ticagrelor P2Y12 inhibitors, Rivaroxaban Xa inhibitor
- Clopidogrel 30% patients assumed pharmacogenetically resistant
Assess baseline S/S
β blockers & other chronic medications

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19
Q

Peripheral Revascularization Indications

A

Acute ischemia d/t emboli, thrombus, or pseudoaneurysm postop (femoral line)
Chronic ischemia d/t atherosclerotic plaque progressively narrowing the vessels - claudication w/ eventual vessel thrombosis

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20
Q

Acute Ischemia

A

Irreversible ischemia damage occurs w/in 4-6hrs

  • Urgent thrombolytic therapy and/or angioplasty
  • Arteriography
  • Surgical intervention
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21
Q

Chronic Ischemia

A

Surgery indicated when severe disabling claudication & critical limb ischemia (limb salvage)

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22
Q

Peripheral Revascularization

Surgical Approach

A 
Donor artery or vein w/ unobstructed blood flow exposed (common femoral, superficial femoral, or deep femoral)
Target distal artery (recipient) exposed at or below the knee (dorsalis pedis or posterior tibial arteries)
Tunnel created & graft passed
Heparin IV (does not require reversal)
Anastomosis constructed & arteriogram to conform adequate blood flow
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23
Q

Peripheral Revascularization

Monitoring

A 
Continuous EKG monitoring w/ ST analysis
A-line
CVP or PA catheter
Foley to monitor I/Os (intravascular volume)
Minimal blood loss & 3rd spacing
Regional or general approach
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24
Q

Peripheral Revascularization

Emergency Surgery Considerations

A 
Monitor K+ levels
Myoglobinemia
Fasciotomy?
Coagulation status
EKG ischemia
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25
Q

Peripheral Revascularization

Regional vs. General

A

Assess coagulopathy or anticoagulation therapy
Spinal best to avoid hematoma
No difference b/w regional & general based on cardiopulmonary complications
Regional 5x superior to general r/t graft occlusion complication rates

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26
Q

Graft Occlusion

A

Significant w/ general anesthesia approach in postop period
Hypercoagulable state
↓fibrinolysis → fibrinogen not broken down & clots form
↑Epi/NE/cortisol
Graft patency maintained w/ regional 2° ↑blood flow w/ sympathectomy

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27
Q

Peripheral Revascularization

Anesthetic Management Intraop

A

AVOID vasopressors
Keep feet warm

Regional:

  • L1 → L4 dermatomes
  • T10 level adequate
  • Epidural dosing 9-12mL including test dose (elderly patients require ↓dosing)

General:

  • Balanced anesthetic w/ opioids, inhalational agent, N2O, & neuromuscular blocker
  • Minimal opioids to facilitate extubation
  • Deepen anesthetic during tunneling phase (3-5mcg/kg Fentanyl)
  • Avoid hemodynamic extremes (β blockers often necessary)
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28
Q

Peripheral Revascularization

Anesthetic Management Postop

A 
Stress reduction & pain control 
↑MI risk postop
Continuous EKG monitoring w/ ST analysis
Control HR & BP
Avoid anemia Hgb < 9g/dL
Frequent peripheral pulse checks
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29
Q

LE Endovascular

A

Less invasive procedure to deploy stent & improve artery patency
General, neuraxial, or MAC
Percutaneous procedures (often MAC sedation)
Open access (femoral stenosis) consider GA

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30
Q

Carotid Artery Disease

A

1° carotid artery disease cause = atherosclerosis

Commonly occurs at the common carotid artery & internal/external carotid arteries

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31
Q

Carotid Artery Disease S/S

A

Fatal or debilitating stroke
TIA
Amaurosis fugax (transient monocular blindness attack)
Asymptomatic bruit

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32
Q

___ % strokes are ___

A

Approximately 87% strokes are ischemic (cerebral thrombosis or embolism)

< 20% strokes are preceded TIA

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33
Q

What disease accounts for up to 20% all strokes?

A

Extracranial atherosclerotic

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34
Q

Carotid Endarterectomy

Indications

A

↓symptoms & prevent stroke
Most common peripheral vascular surgery

Symptomatic patients w/ 70-99% carotid stenosis

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35
Q

How to manage asymptomatic < 70% carotid stenosis?

A 
Medical therapies (ASA)
Percutaneous angioplasty/stenting
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36
Q

Carotid Endarterectomy

Preop Assessment

A

Ask about recent symptoms? MI or TIA
Optimize medical management
- β blocker, statins, antiplatelet therapy
- HTN control, restore intravascular volume, reset cerebral autoregulation
- Diabetes control
Coronary artery disease common (1st treat carotids d/t CABG bypass & impaired cerebral perfusion w/ carotid plaques)
- Assess coronary angiograms

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37
Q

SIGNIFICANT Coronary Artery Disease S/S

A

Unstable angina
Decompensated heart failure
Significant valve disease

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38
Q

Carotid Endarterectomy

Anesthetic Management

A 
Awake vs. GETA
Continue ASA & cardiac medications
Type & screen
EKG to monitor leads II & V - rhythm disturbances & ST segment changes
Cerebral oximeter
A-line
ACTs intraop
Central line rare
PIV x2
Fluid warmer
Lower body warmer
Arms tucked
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39
Q

Anterior Leads

A

V3 & V4

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40
Q

Inferior Leads

A

II, III, & AVF

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41
Q

Lateral Leads

A

I, AVL, V5, & V6

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42
Q

Septal Leads

A

V1 & V2

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43
Q

Carotid Endarterectomy

Medications & Infusions

A

Phenylephrine 20-300mcg/min OR 0.15-0.75mcg/kg/min
Remifentanil 0.05-0.2mcg/kg/min
Clevidipine 1mg or 1-2mg/hr double every 90sec up to 32mg/hr
Nitroglycerin
β blockers (Labetalol 5mg, Esmolol 10mg or 100-300mcg/kg/min, Metoprolol 1mg)
Ephedrine 5-10mg
Heparin & Protamine

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44
Q

Carotid Endarterectomy

MAP Goals

A

High-normal range especially during carotid clamping to increase collateral flow & prevent cerebral ischemia

Potential to induce HTN 10-20% above baseline during carotid clamping
Careful to prevent ↑MVO2

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45
Q

What response will be anticipated in response to carotid sinus manipulation? Why?

A

Bradycardia & HoTN d/t the baroreceptor reflex

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46
Q

How to treat sudden bradycardia & HoTN?

A

Stop surgical manipulation

Ask surgeon to infiltrate the carotid bifurcation w/ 1% Lidocaine to prevent further episodes

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47
Q

Where are baroreceptors located?

A

Carotid sinuses & aortic arch

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48
Q

Carotid Endarterectomy

Emergence

A

Assess neuro status - deficits require immediate attention (angiography, reoperation, or both)
HTN & tachycardia associated w/ emergence & extubation
- Consider β blocker or sedation to smooth emergence
↑pressure stresses the new suture lines

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49
Q

Awake Carotid Endarterectomy

A

Best way to monitor function
Patient has ball to squeeze Q5min checks
Minimal or NO sedation (Midazolam 0.5mg + Fentanyl 25mcg) to prevent interference w/ neurological assessment
Avoid Propofol
Consider Esmolol during induction/direct laryngoscopy to prevent sympathetic response
Patients potentially get hot & restless under the drapes
Uncover their legs
Prevent/treat HTN or HoTN

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50
Q

Awake Carotid Endarterectomy

Regional Anesthesia

A

Cervical plexus block to C2-C4 dermatomes
↓shunts indication
Improved hemodynamic stability
Reduced costs (operative time & avoid cerebral oximetry sensors)
Requires patient cooperation*

51
Q

Cervical Plexus Block

A

Identify posterior sternocleidomastoid border
Inject along the posterior border medial surface
Potential to block accessory nerve → trapezius muscle paralysis

52
Q

GALA Trial

A

Multicenter RCT
Carotid endarterectomy under general or local anesthesia

Finding = anesthetic technique was not associated w/ any significant difference b/w general vs. local

53
Q

Cerebral Autoregulation

A

Hypocapnia ↓CO2 → vasoconstriction ↓CBF

Hypercapnia ↑CO2 → vasodilation ↑CBF

54
Q

Carotid Artery Stump Pressure

GOAL

A

> 50mmHg

Stump pressure represents the back-pressure resulting from collateral flow through the circle of Willis via contralateral carotid artery & vertebrobasilar system

55
Q

NIRS

A

Near-infrared spectrophotometry

Non-invasive technique to continuously monitor regional cerebral O2 saturation
Approximates VENOUS blood O2 saturation

56
Q

Carotid Endarterectomy

Postop Complications

A

Thromboembolic & hemorrhage intracerebral events
HTN common d/t surgical carotid sinus baroreceptors denervation
HoTN common d/t baroreceptor hypersensitivity or reaction
Cerebral hyper-perfusion syndrome - abrupt ↑blood flow w/ loss autoregulation (S/S include headache, seizure, focal neurological deficits, cerebral edema, or intracerebral hemorrhage)
Cranial & cervical nerve dysfunction - RLN or SLN, hypoglossal, mandibular
- Bilateral RLN injury → bilateral vocal cord paralysis → life-threatening upper airway obstruction
Carotid body denervation - impaired ventilatory response to mild hypoxemia, central chemoreceptors impaired, worsened w/ opioid administration
Wound hematoma → requires immediate surgical intervention d/t airway impingement

57
Q

Endovascular Carotid Artery Stenting

A

Percutaneous transluminal angioplasty & stenting

  1. Femoral access
  2. Aortic arch angiogram
  3. Selective common carotid artery origin & angiogram cannulation
  4. Guidewire placement into the external carotid
  5. Place embolic protection device
  6. Balloon angioplasty the lesion, advance stent delivery catheter across dilated lesion, deploy self-expanding stent, & stent balloon dilation
  7. Complete angiogram
  8. Access site management (hold pressure)
58
Q

Aortic Diseases

A

Peripheral arteries - occlusive disease
Aorta & 1° branches
- Aneurysms
- Dissections

59
Q

Aortic Aneurysm

A

Often medically managed
Dilation all 3 arterial layers
Occasionally produces symptoms d/t compression on surrounding areas

60
Q

Aortic Aneurysm S/S

A

Asymptomatic

Present w/ pain d/t compressing adjacent structures or vessels

61
Q

Aortic Aneurysm Diagnosis

A

CXR
Echo
CT/MRI
Angiography

62
Q

Aortic Dissection

A

Surgical EMERGENCY
Mortality up to 58%
Occurs when blood enters the medial layer (minutes to hours)
Initially presents w/ tear in the intima layer

63
Q

Aortic Dissection S/S

A

Severe pain in the posterior chest or back pain

64
Q

Aortic Dissection Diagnosis

A

Unstable - Echo

Stable - CXR, CT/MRI, aortography, Echo

65
Q

AAA

A

Abdominal aortic aneursym
Adventitial elastin degradation w/in vessels - genetic, biochemical, metabolic, infectious, mechanical, & hemodynamic factors

Concomitant aortoiliac occlusive disease present approximately 20-25% AAA patients

66
Q

Abdominal Aortic Aneurysm

Risk Factors

A

Elderly male
Smoker
Family history (genetic component)
Atherosclerosis & HTN

67
Q

Abdominal Aortic Aneurysm S/S

A

Asymptomatic pulsatile abdominal mass

68
Q

Abdominal Aortic Aneurysm

Causes

A

Trauma
Mycotic infection (bacterial)
Syphilis
Marfan syndrome

69
Q

AAA Repair

A

> 6cm diameter
Symptomatic < 5.5cm aneurysms
Expand > 0.5cm in 6mos period

5.5-5.9cm aneurysms are controversial, but often medically managed

70
Q

Open Abdominal Aortic Reconstruction

A

More complex than CABG (no perfusionist or bypass pump)
Extensive incision & dissection
Clamping & unclamping the aorta & major branches → physiologic changes
Varying organ ischemia-reperfusion duration
Fluid shifts
Temperature fluctuations
Neurohumoral & inflammatory responses activated

71
Q

What classifies AAA as relatively benign in terms rupture & expansion?

A

< 4cm diameter

72
Q

LaPlace

A

↑diameter ↑wall tension (even when arterial pressure remains constant)
Systemic HTN enhances aneurysm enlargement

73
Q

Ruptured AAA

A

Periop mortality ≈50%

74
Q

Ruptured AAA Clinical Presentation

A

Classic triad:

  1. Hypotension
  2. Back pain
  3. Pulsatile abdominal mass (not always present after aneurysm ruptures)
75
Q

EVAR

A

Endovascular abdominal aortic aneurysm repair
Less invasive
Reduced morbidity & mortality
↓hospital LOS

Now most common technique to repair AAA

76
Q

EVAR Anesthetic Considerations

A

MAC sedation w/ local or regional vs. general
Patient able to lay supine, co-morbidities, aneurysm complexity, & surgical urgency (full stomach → RSI)
Steering guide sheaths require L arm arterial cut down
Hemodynamic management
Preserve organ perfusion
Blood loss & intravascular volume
Temperature
Radiation safety (fluroscopy)

77
Q

Spinal Cord Blood Supply

A

Extensive collateral circulation
Anterior artery x1 (supplies ≈75%)
- Artery of Adamkiewics AKA originates off the descending aorta b/w T9-T12 & supplies lower 2/3 spinal cord 1°
Posterior arteries x2 (supplies ≈25%)

78
Q

Early EVAR Complications

A 
Paraplegia
Stroke
Acute renal injury
Aneurysm rupture
Pelvic hematoma
79
Q

Late EVAR Complications

A 
Endoleaks
Aneurysm rupture
Device migration
Limb occlusion
Graft infection
80
Q

Endoleaks Treatment

A

Balloon angioplasty to the proximal attachment site to obtain to desired seal via remodeling the stent-graft
Type II - transarterial embolization via iliac arteries or retrograde embolization through the superior mesenteric or inferior mesenteric arteries
Last resort = open surgical treatment

81
Q

CIN

A

Contrast induced nephropathy
PRESERVE trial

  1. Contrast load
  2. Pre-existing kidney disease

Limit contrast load & ensure adequate hydration to ↓iodine-based dyes viscosity

82
Q

Aortoiliac Occlusive Disease

A

Most common sites chronic atherosclerosis = infrarenal aorta & iliac arteries
Surgical intervention only when patients are symptomatic

83
Q

AORTIC CROSS-CLAMP

Factors to Consider

A

Pathophysiological changes are complex & depend on the following factors:

  • Clamp level
  • L ventricle status
  • Degree periaortic collateralization
  • Intravascular blood volume & distribution
  • SNS activation
  • Anesthetic drugs & techniques
  • Heparinization
84
Q

AORTIC CROSS-CLAMP

Complications

A

Arterial HTN above the clamp & HoTN below the clamp

ISCHEMIA → renal failure, hepatic ischemia, coagulopathy, bowel infarction, paraplegia

85
Q

Aortic Cross-Clamp

Left Ventricle

A

↑LV volume & pressure
Healthy heart no significant ventricular distention or dysfunction
Impaired or stiff heart w/ ↓myocardial contractility & coronary reserve → ventricular distention → acute LV dysfunction & myocardial ischemia

86
Q

Baroreceptor response to aortic cross-clamp:

A

↑aortic pressure

↓HR/contractility/vascular tone

87
Q

Aortic Cross-Clamp

Metabolic Effects

A

↓O2 consumption 50%
Blood flow via tissues & organ below the aortic occlusion remains dependent on perfusion pressure
Independent from cardiac output

88
Q

Physiological changes associated w/ aortic cross-clamp

A 
HEMODYNAMIC
Acute ↑SVR ↓CO
↑arterial BP above the clamp
↓arterial BP below the clamp
↑segmental wall abnormalities
↑LV wall tension
↓ejection fraction
↑pulmonary occlusion pressure
↑central venous pressure & coronary blood flow
↓renal blood flow
METABOLIC
↓total body O2 consumption & CO2 production
↑mixed venous O2 saturation
↓total body O2 extraction
↑Epi/NE
Respiratory alkalosis & metabolic acidosis
89
Q

Aortic Cross-Clamp

Anesthetic Management

A

Vasodilators ↓afterload, wall stress, & MVO2 (Nitroprusside, NTG, Nicardipine, & Clevidipine)
Avoid long-acting medications
Perfusion to distal organs dependent on collateral circulation that originates proximal to the clamp or shunts

90
Q

Aortic Cross-Clamp

Placement

A

Higher the clamp level → more significant impact on perfusion to vital organs
Thoracic > supraceliac > infrarenal

91
Q

Aortic Cross-Clamp

Renal Effects

A

Aortic cross-clamping ABOVE the renal arteries ↓renal blood flow
Renal sympathetic blockade w/ epidural anesthesia to T6 level does not prevent or modify the severe impairment in renal perfusion & function

92
Q

Renal failure after AAA repair

A

Pre-existing renal dysfunction
Ischemia during cross-clamp time
Thrombus or embolus interrupts RBF
Hypovolemia or HoTN

93
Q

Renal Protection

A

Mannitol, loop diuretics, methylprednisolone, & low-dose Dopamine 1-3mcg/kg/min are used clinically to preserve renal function during aortic surgery

94
Q

Mannitol

A

Renal protection
12.5g per 70kg
Improves renal cortical blood flow during infrarenal aortic cross-clamping & reduces ischemia-induced renal vascular endothelial cell edema & vascular congestion

*Also acts to scavenge free radicals, ↓renin secretion, & ↑renal prostaglandin synthesis

95
Q

What patients are most vulnerable to the stress imposed on the cardiovascular system during aortic cross-clamping?

A

Patients w/ pre-existing impaired ventricular function & reduced coronary reserve

96
Q

Pre-existing cardiac impaired ventricular function & reduced coronary reserve goals during aortic cross-clamping:

A
  1. Reduce afterload (Nitroprusside or Clevidipine)
  2. Maintain normal preload (IV fluids)
  3. Maintain CO (inotropes & MAP goals)
97
Q

How to prepare prior to aortic UNclamping

A

↓volatile anesthetics
↓vasodilators or discontinue
↑fluid administration (volume)
↑vasoconstrictors

Severe HoTN unresponsive to interventions notify surgeon to reapply the cross-clamp
Consider Mannitol or NaHCO3

97
Q

Open AAA

Anesthetic Considerations

A 
Central line
PIV x2
A-line
Cross-matched blood
*Rapid blood loss possible
TEE
Cerebral oximetry
Esmolol, Nitroprusside, NTG, Clevidipine, Phenylephrine
Heparin 100-300u/kg + Protamine to reverse
Monitor ACTs
Postop pain consider epidural
Forced upper air warmer
Fluid warms
Do NOT warm the lower body during cross-clamp ↑injury to ischemia distal tissues d/t ↑metabolic demand (MVO2)
98
Q

Aneurysm Hemodynamic Management

A

Avoid HTN d/t acute stress on the aneurysm → rupture
Maintain HR at or below baseline to prevent myocardial ischemia
Defer euvolemic resuscitation until aortic rupture surgically controlled ↑volume ↑pressure ↑bleeding

99
Q

AAA

Postop Considerations

A

Aggressively control HTN & tachycardia
Achieve hemodynamic, metabolic, & temperature homeostasis prior to extubation
LOS variable
Pain - epidural vs. PCA

100
Q

AAA Complications

A 
Myocardial infarction
Pneumonia (pulmonary edema)
Sepsis
Renal failure
↓tissue perfusion
Hypothermia
101
Q

Thoracic Aortic Aneurysm

A

Associated w/ known genetic syndromes

  • Marfan syndrome
  • Ehlers-Danlos syndrome
  • Bicuspid aortic valve
  • Non-syndromic familial aortic dissection
102
Q

Marfan Syndrome

A

Caused by mutations in the fibrillin-1 gene

103
Q

Ehlers-Danlos Syndrome

A

Connective tissue disorder

19 different genetic manifestations

104
Q

Bicuspid Aortic Valve

A

Most common congenital anomaly resulting in aortic dilation/dissection
Occurs in 1% population

105
Q

TAA Repair Approach

A

Descending aorta - L posterolateral thoracotomy w/ one-lung ventilation
Ascending aorta - supine w/ median sternotomy

Full or partial cardiopulmonary bypass

106
Q

Thoracic Aortic Aneurysm

S/S

A

Typically reflects impingement on nearby structures

  • Hoarseness d/t L RLN stretch
  • Stridor d/t trachea compression
  • Dysphagia d/t esophagus compression
  • Dyspnea d/t lung compression
  • Edema d/t superior vena cava compression
107
Q

Thoracic Aortic Dissection

A

MI presentation
Acute, severe sharp pain in the anterior chest/neck or b/w the shoulder blades
Diminished or absent peripheral pulses

108
Q

TAA Crawford Classification

Type I

A

Aneurysm involving descending thoracic & upper abdominal aorta

109
Q

TAA Crawford Classification

Type II

A

Descending thoracic & most abdominal aorta

*Most difficult to repair

110
Q

TAA Crawford Classification

Type III

A

Lower thoracic aorta & most abdominal aorta

*Most difficult to repair

111
Q

TAA Crawford Classification

Type IV

A

Most or all abdominal aorta

112
Q

DeBakey Classification
Dissection Aortic Aneurysms
Type I

A

Ascending aortic tear w/ dissection down entire aorta

113
Q

DeBakey Classification
Dissection Aortic Aneurysms
Type II

A

Tear in the ascending aorta w/ dissection limited to only the ascending aorta

114
Q

DeBakey Classification
Dissection Aortic Aneurysms
Type III

A

Tear in the proximal descending thoracic aorta w/ dissection from thoracic aorta to abdominal aorta

115
Q

What cross-clamp timeframe correlates w/ minimal paraplegia risk?

A

< 30minutes

116
Q

Artery or Adamkiewics

A

Anterior radicular artery
Exits the spinal cord at T9-T12
Supplies 1° blood flow to lower 2/3 spinal cord

117
Q

Anterior Spinal Artery Syndrome

A

LE flaccid paralysis & bowel/bladder dysfunction

Sensation & proprioception are spared

118
Q

Spinal Cord Protection

A

Limit cross-clamp time < 30min
Distal aortic perfusion (extracorporeal support)
CSF drainage ↓spinal cord perfusion pressure (CSF pressure ↑10-15mmHg w/ cross-clamping)
Intrathecal papaverine
Mild hypothermia ↓O2 requirements 5% each 1°C
Do NOT actively warm the LE d/t ↑metabolic requirements, acidosis, & ischemic injury
Barbiturates & corticosteroids
Avoid hyperglycemia

119
Q

When to extubate after aneurysm repair?

A

Patient fully awake
Consider extubating in ICU d/t intraop fluid shifts
Notify ICU team when paralytic not reversed

120
Q

Ruptured Aneurysm

EMERGENCY

A

Open or endovascular approach
Awake intubation vs. RSI w/ Etomidate 0.1mg/kg
14-16G PIVs
PRBCs
Rapid-infuser
Maintain normothermia
Dopamine, Epi/NE, Vasopressin
Place A-line, central line, & PA catheter after induction
TEE to assess ventricular function & filling pressures

121
Q

Induction Medications

A

Fentanyl 10-15mcg/kg or Sufentanil 1-2mcg/kg
Etomidate 0.1-0.3mg/kg
Esmolol 100-500mcg/kg or Sodium nitroprusside 25-50mcg or Nitroglycerin 0.5-3mcg/kg
Lidocaine 1.5mg/kg
Rocuronium 1-2mg/kg
Hemodynamically stable patients Scopolamine 400mcg (amnesia)

122
Q

Maintenance Medications

A

Narcotic/benzodiazepine
Low-dose volatile anesthetic Iso 0.3-0.5% or Sevo 0.5-1%
Epidural Morphine 2-4mg or Hydromorphone 0.5-0.8mg
Remifentanil 0.05-0.2mcg/kg/min

123
Q

Cross-Clamp Medications

A 
BEFORE:
- Mannitol 0.25-0.5g/kg & Furosemide 20-40mg
- Heparin 100-300units/kg
DURING:
- Nitroglycerin 0.5-2mcg/kg/min and/or 100mcg bolus
- Sodium nitroprusside 0.5-2mcg/kg/min
- Esmolol 50-300mcg/kg/min
AFTER:
- Volume

AS - N934 Advanced Principles II (18 decks)

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