Mod X: Anesthesia for Surgery of the Aorta

Question 1

Anesthesia for Surgery of the Aorta

OBJECTIVES:

Answer 1

1. Identify the risk factors and causative factors of thoracoabdominal aneurysm development
2. Familiarity with aneurysm and dissection classifications
3. Discuss surgical treatment for thoracic aneurysm repair
4. Discuss anesthetic management for thoracic aneurysm repair
5. Discuss postoperative management of these patients

Question 2

_{THORACOABDOMINAL AORTIC ANEURYSM}

an enlargement of the aorta greater than or equal to 3.0 cm in diameter is the definition of:

Answer 2

Aneurysm

Question 3

_{THORACOABDOMINAL AORTIC ANEURYSM​}

When was the First repair performed? what was the mortality rate at that time?

Answer 3

1951

(mortality rate was 20%)

Question 4

_{THORACOABDOMINAL AORTIC ANEURYSM​}

What factors have contributed in the reduction in the mortality rate of THORACOABDOMINAL AORTIC ANEURYSM​ repairs to 2.5% today?

Answer 4

Improvements in surgical and anesthetic management

Question 5

_{THORACOABDOMINAL AORTIC ANEURYSM​}

What’s the most important predictor of rupture of an aneurysm?

Answer 5

Size of aneurysm

Question 6

_{THORACOABDOMINAL AORTIC ANEURYSM​}

Mortality rate of ruptured aneurysm is

Answer 6

85%

Question 7

_{THORACOABDOMINAL ANEURYSM}

most significant risk factor for developing a AAA is

Answer 7

Age

Question 8

_{THORACOABDOMINAL ANEURYSM}

Risk Factors for developing a THORACOABDOMINAL ANEURYSM in general include:

Answer 8

Age (most important risk factor)

Gender : Men > women; White males =most common

Smoking (hx of <0.5 ppd, for up to 10 yrs carries inc risk for AAA - This inc is dose dependent => smoking 1 ppd for 35 yrs has a 12-fold risk for AAA development - Smoking also inc the rate of aneurysm enlargement by 35%)

Increased salt intake - Sedentary lifestyle - HTN

Concomitant PAD and CVD - Diabetes

Family history of AAA (1st degree relatives of a pt w/ AAA have apprx 20% likelyhood for the dvpt of AAA)

Renal insufficiency

Question 9

_{THORACOABDOMINAL ANEURYSM}

Causative factors

Answer 9

Aortic aging and atherosclerosis = most common causative factors (80%)

Aortic dissection (17%)

Actual etiology unknown

Question 10

_{THORACOABDOMINAL ANEURYSM}

Rare causes:

Answer 10

Trauma

Mycotic infection

Syphilis

Takayasu arteritis

Marfan Syndrome

Question 11

_{AORTIC DISSECTION}

AORTIC DISSECTION is calssified depending on:

Answer 11

Extent of Aortic involvement

Question 12

_{AORTIC DISSECTION}

Classification systems

Answer 12

DEBAKEY CLASSFICIATIONS (Type I - Type III)

STANFORD CLASSIFICATION (Type A - Type B)

Question 13

_{AORTIC DISSECTION - DEBAKEY CLASSFICIATIONS}

Dissection from ascending aorta throughout entire aorta

Answer 13

Type I

Question 14

_{AORTIC DISSECTION - DEBAKEY CLASSFICIATIONS}

Dissection confined to ascending aorta

Answer 14

Type II

Question 15

_{AORTIC DISSECTION - DEBAKEY CLASSFICIATIONS}

Why are Type I and Type II dissection typically a/w aortic regurgitation?

Answer 15

Type I and Type II typically involve the aortic valve and cause aortic regurgitation

Question 16

_{AORTIC DISSECTION - DEBAKEY CLASSFICIATIONS}

Dissection that begins just distal to left subclavian artery and extend to diaphragm

Answer 16

Type IIIa

Question 17

_{AORTIC DISSECTION - DEBAKEY CLASSFICIATIONS}

Dissection that begins distal to left subclavian and extends pass the diaphragm, to the aortoiliac bifurcation

Answer 17

Type IIIb

Question 18

_{AORTIC DISSECTION - STANFORD CLASSIFICATION}

Dissection that involves the ascending aorta

Answer 18

Type A

Question 19

_{AORTIC DISSECTION - STANFORD CLASSIFICATION}

Dissection that does not involve ascending aorta

Answer 19

Type B

Question 20

_{THORACOABDOMINAL ANEURYSM}

Dilation of the descending aorta that extend into the abdominal aorta to the iliac arteries

Answer 20

THORACOABDOMINAL ANEURYSM

Question 21

_{THORACOABDOMINAL ANEURYSM}

Classification:

Answer 21

THORACOABDOMINAL ANEURYSMs were classified in 1983 by CRAWFORD (Type I through Type IV)

Question 22

_{THORACOABDOMINAL ANEURYSM - CRAWFORD CLASSIFICATION}

Aneurysm that extend from the origin of the left subclavian to suprarenal abdominal aorta

Answer 22

Type I

Question 23

_{THORACOABDOMINAL ANEURYSM - CRAWFORD CLASSIFICATION}

Aneurysm that extend from the subclavian artery to the aortoiliac bifurcation

Answer 23

Type II

This is the most extensive type of aneurysm!!!!

Question 24

_{THORACOABDOMINAL ANEURYSM - CRAWFORD CLASSIFICATION}

Aneurysm that extend from the distal thoracic aorta to the aortoiliac bifurcation

Answer 24

Type III

Question 25

_{THORACOABDOMINAL ANEURYSM - CRAWFORD CLASSIFICATION}

Aneurysm that is limited to the Abdominal aorta below diaphragm to the iliac bifurcation

Answer 25

Type IV

Question 26

_{THORACOABDOMINAL ANEURYSM - CRAWFORD CLASSIFICATION}

Which THORACOABDOMINAL ANEURYSMs are the most difficult to repair? why?

Answer 26

Type II and Type III

They include both the thoracic and the abdominal aorta

Question 27

_{THORACOABDOMINAL ANEURYSM - CRAWFORD CLASSIFICATION}

Pts w/ which of THORACOABDOMINAL ANEURYSM are at greatest risk for paraplegia and renal failure? why?

Answer 27

Type II

D/t spinal cord and kidney ischemia

Question 28

_{THORACOABDOMINAL ANEURYSM}

Physical examination

Answer 28

Has only a moderate sensitivity to detection

Should not be excluded

Aorta becomes more elongated and elarged w/ age

Palpation of pulsatile mass can be variable

Focused examination should be directed at upper abdominal quadrants

Palpitation does not precipitate rupture

Oftentimes incidentally found (prevalence of undiagnosed AAA 10%)

Question 29

_{THORACOABDOMINAL ANEURYSM - Assessment of comorbidities}

What are the leading causes of early and late death after surgical repair of THORACOABDOMINAL ANEURYSM?

Answer 29

Cardiovascular and pulmonary disease

Pt’s Cardiovascular condition should be determined

If there is not active cardiac condition present, further testing typically only necessary if it would change the course of treatment

If Met Score > or = 4, No further studies are required

Question 30

_{THORACOABDOMINAL ANEURYSM}

Tests to Assess other comorbidities

Answer 30

12-lead EKG

^{(all pts w/in 30 days of repair)}

TTE/TEE

_{(recommended in pts that have SOB of unknown origin or worsening SOB)}

Chest X-ray

Pulmonary function testing

^{(COPD - Most important complications to look for are atelectasis, pneumonia, resp failure, exacerbation of COPD especially if the pt is to undergo open AAA surgery)}

Aneurysm imaging

^{(while CT imaging is more reporducible, Ultrasound has been proven to detect the presence AAA accurately and efficiently)}

CBC, CMP, coagulation testing, T&S/T&C for blood products

^{(Type and cross-matching is improtant - the presence of AAA influences bothe platelets count and function. Low plt count has been observed in pts w/ AAA, and is attributable to an increase in plts destruction in the aneurysm sac. It’s recommended that plt counts < 150K be addressed. lower pre-op plt counts have been identified as an independent predictor of 2-yr mortality among pts undergoing repair)}

Hemoglobin

^{(Hgb concentration should be maintained > 9 in vascular pts, epecially in those at significant risk for ischemic cardiac morbidity)}

Blood loss

^{(Blood loss for these procedures can be very profound, and it can potentially require the need for massive transfusion)}

Question 31

_{THORACOABDOMINAL ANEURYSM}

Table summarizing “Pre-op cardiac evaluation for the pt undergoing aneurysm repair”

Answer 31

“Pre-op cardiac evaluation for the pt undergoing aneurysm repair”

Question 32

_{ASSESSMENT OF RENAL FUNCTION}

Chronic renal disease is common in vascular surgery and is associated with increased risk for

Answer 32

death and cardiovascular disease

Question 33

_{ASSESSMENT OF RENAL FUNCTION}

Causes of renal artery stenosis

Answer 33

Atherosclerosis, diabetes, HTN

Question 34

_{ASSESSMENT OF RENAL FUNCTION}

How does Pre-op renal insufficiency affect post outcomes?

Answer 34

Pre-op renal insufficiency increases the risk of pot-op renal failure

Pts who develop post-op renal failure have a higher incidence of mortality

Question 35

_{ASSESSMENT OF RENAL FUNCTION}

What’s a Strong predictor of long-term mortality in patients with symptomatic lower extremity arterial occlusive disease?

Answer 35

Pre-op assessment of renal function

Question 36

_{ASSESSMENT OF RENAL FUNCTION}

Which two lab values are used to assess renal function?

Answer 36

Serum creatinine and creatinine clearance

Question 37

_{ASSESSMENT OF RENAL FUNCTION}

Preoperative serum creatinine of which level is an independent risk factor for cardiac complications after major non-cardiac surgery?

Answer 37

Preoperative serum creatinine level >2 mg/dL

Question 38

_{ASSESSMENT OF RENAL FUNCTION}

Creatinine clearance of which value is an independent perdictor of both short term and long term mortality after elective vascular surgery?

Answer 38

Creatinine clearance < 60 mL/minute

Question 39

_{THORACOABDOMINAL ANEURYSM}

How can THORACOABDOMINAL ANEURYSM be medically managed?

Answer 39

Alterations in midfiable risk factors (e.g. smoking and BP)

Question 40

_{THORACOABDOMINAL ANEURYSM}

What are the are the greatest predictors of risk of rupture?

Answer 40

Diameter and rate of expansion

Question 41

_{THORACOABDOMINAL ANEURYSM}

Elective repair should occur in patients with:

Answer 41

Presence of aortic dissection

Aneurysm diameter of 5.5 cm

Active symptoms (chest pain, back pain)

Aneurysm growth of 0.5 cm within 6 month period

Question 42

_{THORACOABDOMINAL ANEURYSM}

Why would pts with both aortic aneurysm and aortic valve insufficiency undergo both aortic valve replacement and ascending aortic repair, even if the size of the aneurysm is less than 5.5 cm?

Answer 42

The aortic insufficiency cmay be exacerbated by the presence of an aneurysm

Question 43

_{THORACOABDOMINAL ANEURYSM MONITORING}

Appropriate monitoring for anuerysm surgery depends on:

Answer 43

Complexity of the procedure

Not all pts requier extensive invasive monitoring

Consider risk for fluid shift and blood loss, these can be profound

Consider physiologic changees a/w cross clamping the aorta

Question 44

_{THORACOABDOMINAL ANEURYSM MONITORING}

Monitoring for AAA surgery will include:

Answer 44

Standard monitors, including 5-lead EKG

Pulse oximetry

Invasive monitoring and venous access

Large bore IVs or introducer

Arterial line

^{Radial artery most common}

^{(Right side placement. Occlusion of aorta proximal to L SCA may be necessary)}

^{Loss of tracing = L subclavian artery occlusion}

^{Note discrepancy between right and left arms}

Pulmonary artery catheter

^{Not routine, but should be considered in patients with LV dysfunction}

Question 45

_{THORACOABDOMINAL ANEURYSM MONITORING}

Why is it especially important for pt undegoing AAA surgery to have a 5-lead EKG?

Answer 45

Ischemic cardiac morbidity is the leading cause of peri-op death in the US, and is strong predictor of adverse cardiac events after vascular surgery

Question 46

_{THORACOABDOMINAL ANEURYSM MONITORING}

What’s the most common site for arterial line placement in vascular surgery

Answer 46

Radial artery

Question 47

_{THORACOABDOMINAL ANEURYSM MONITORING}

To avoid hypotension, arterial pressures should be verified in both arms in these pts - why?

Answer 47

Vascular surgery pts tend to have a large discrepency btw R and L-sided BPs

This is D/t the atherosclerotic lesions in the subclavians and/or axillary arteries

This can cause a falsely low BP in the ipsolateral arm

Question 48

_{THORACOABDOMINAL ANEURYSM MONITORING}

Vascular surgery pts tend to have a large discrepency btw R and L-sided BPs - Which arm should be should be used for monitoring during surgery?

Answer 48

The arm w/ the higher pressure should be should be used for monitoring during surgery

Question 49

_{THORACOABDOMINAL ANEURYSM MONITORING}

Minimum for central monitoring

Answer 49

Some type of central access

However, use of CVP and PA catheters remains controversial eventhough they are widely used

Do not always reflect pt’s intravascular volume

Therefore, SV and CO should also be considered

Question 50

_{THORACOABDOMINAL SURGICAL REPAIR}

Two ways to repair aneurysm

Answer 50

Open repair (esp. if ascending aorta is concrened)

Endovascular repair (descending aorta and below)

Question 51

_{THORACOABDOMINAL SURGICAL REPAIR - Open repair}

Aneurysms of aortic arch done with

Answer 51

Ellective CBP

Deep hypothermia

and circulatory arrest

This is b/c CBF is interrupted while the graft repair is made around the R. subclavian and/or the L. common carotid artery

Question 52

_{THORACOABDOMINAL SURGICAL REPAIR - Open repair}

Repair of Aneurysms involving the thoracic aorta via the open approach will typically be done through which type of incision?

Answer 52

Repair of Aneurysms involving the thoracic aorta (Descending thoracoabdominal aneurysms) via the open approach will typically be done through a thoracoabdominal incision (Left thoracoabdominal approach = favored)

Pt will be positionned in a Right-lateral decubitus poisition

One-lung ventilation via a double-lume ET tubeshould initiated for aortic root reconstruction

Aortic Cross clamping at the neck of the aneurysm

Can be done with or without extracorporeal circulation

Aneurysm is incised

B/c of the Aortic Cross clamping, the operation must be done expeditiously

Should limit aortic cross clap time!

Question 53

_{MANAGEMENT OF AORTIC CROSS CLAMPING}

Occlusion of aorta is associated with:

Answer 53

Profound physiologic changes

The higher the clamp is placed, the more severe and detrimental the changes are

Question 54

_{MANAGEMENT OF AORTIC CROSS CLAMPING}

Which clamping carries the highest risk of most clampings?

Answer 54

Supraceliac clamping

Supraceliac clamping carries the highest risk of most clamping

Supraceliac clamping produces greatest hemodynamic stress

^{Renal failure, mesenteric/hepatic ischemia, massive blood loss, coagulopathy, myocardial dysfunction}

Question 55

_{MANAGEMENT OF AORTIC CROSS CLAMPING​}

Which aortic cross-clamping has least cardiovascular response?

Answer 55

Infrarenal aortic cross-clamping

Infrarenal aortic cross-clamping has least cardiovascular response

Question 56

_{MANAGEMENT OF AORTIC CROSS CLAMPING​}

Metabolic acidosis during cross clamping is caused by

Answer 56

Cessation of blood flow below the level of cross-clamping

Aerobic metabolism => anaerobic metabolism below level of cross-clamping

Metabolic acids and CO2 are being produced but they remain stagnant in the area distal to the cross-clamp

Elevated lactate levels begin during cross-clamping and peak with removal of clamp

Signs of acidosis that occur during clamping

The majority of symptoms become apparent once the clamp is removed

This is the most critical time as most of the stagnant blood becomes mobilized again

Question 57

_{MANAGEMENT OF AORTIC CROSS CLAMPING​}

Proximal hypertension following removal of cross clamping is d/t: How is it managed? what are some concerns to be aware of?

Answer 57

Increased venous return, afterload and CO

Proximal hypertension = expected after cross-clamping

Can be controlled with Sodium Nitroprusside or NTG

Must be careful b/c the use of a vasodilator can cause overperfusion proximal to the cross clamp, and reduce arterial pressures distally

Question 58

_{MANAGEMENT OF AORTIC CROSS CLAMPING​}

Hypertension should occur after cross clamping

If absence of HTN or hypotension occurs, this should trigger:

Answer 58

Assessment of LV function

Volume status, and

whether or not surgical blood loss has occured

Question 59

_{MANAGEMENT OF AORTIC CROSS CLAMPING​}

Percentage change on CV variables on initiation of aortic occlusion during supraceliac vs infrarenal aortic aneurysm surgery

Answer 59

_{Percentage change on CV variables on initiation of aortic occlusion during supraceliac vs infrarenal aortic aneurysm surgery}

Note impact on different CV variables that the level of cross clamping will have

Note that the supraceliac clamping is a/w the greatest percentage of impact on different variables

Question 60

_{RENAL EFFECT OF AORTIC CROSS-CLAMPING}

How do suprarenal and infrarenal cross clamping affect renal blood flow (RBF)?

Answer 60

RBF decreases w/ suprarenal and infrarenal cross clamping

Question 61

_{RENAL EFFECT OF AORTIC CROSS-CLAMPING}

RBF decreases w/ suprarenal and infrarenal cross clampin. The decreased RBF/perfusion could lead to:

Answer 61

ARF

Carries > 30% mortality rate

Question 62

_{RENAL EFFECT OF AORTIC CROSS-CLAMPING}

Factors influencing RBF

Answer 62

Level of Clamp (most important)

Prolonged cross-clamp time

Prolonged hypotension

Question 63

_{RENAL EFFECT OF AORTIC CROSS-CLAMPING}

Level of Clamp (most important). Infrarenal AoX =

Answer 63

RBF ↓ 38%,

Renal vasc. resistance ↑ 75%

Incidence of ARF (3%)

Question 64

_{RENAL EFFECT OF AORTIC CROSS-CLAMPING}

Level of Clamp (most important). Supraceliac AoX =

Answer 64

Arterial inflow to the kidneys is completely stopped, until aortic cross clamp is removed

more profound effect, ↑ of ARF (6%)

Question 65

_{RENAL EFFECT OF AORTIC CROSS-CLAMPING}

What’s the Best predictor of post-op failure?

Answer 65

Preop renal function

The degree of pre-op renal insuffiency is the strongest predictor of post-op renal dysfunction

Intraoperative u/o NOT predicative

Question 66

RENAL EFFECT OF AORTIC CROSS-CLAMPING

•Renal protection strategies

Answer 66

Maintain adequate intravascular volume

^{(most important)}

Maintain adequate myocardial function

^{(preload, contractility, and systemic perfusion pressures)}

Pharmacological interventions

Question 67

_{RENAL EFFECT OF AORTIC CROSS-CLAMPING}

Renal protection strategies - Pharmacological interventions

Answer 67

Pharmacological interventions are Not fully confirmed by research

However, they continue to be used clinically

Mannitol (12.5- 50 G)

^{Given prior to AoX (common) to induce osmotic diuresing and free radical scavenging}

Loop diuretics

Dopamine

Renal dose Dopamine (1-3 mcg/kg) controversial

^{Not as effective - Used more for low u/o after AoX released}

_{(Loop diuretics and Dopamine used to protect the kidneys - intravascular volumes must be monitored closely if used)}

Fenoldopam

^{<strong>(</strong>selective dopamine Type 1 agonist)}

Ultimate goal is maintenance of intravascular volumes, while achieving adequate preload, afterload and CO

Question 68

_{AORTIC UNCLAMPING}

After ther aortic clamping is removed, Hypotension occurs due to:

Answer 68

Pooling blood and dilated lower extremities vessels

Systemic release of local mediators which causes sytemic Acidosis

Surgical Blood loss

The Longer the clamp time, the more hypotension can occur

Question 69

_{AORTIC UNCLAMPING}

The Longer the clamp time, the more hypotension can occur - why?

Answer 69

D/t increased amount of circulating mediators

Question 70

_{AORTIC UNCLAMPING}

Prior to unclamping, some of the hypotension can be attenuated by

Answer 70

Timely discontinuation of dilators

Ensure adequate replacement of blood loss

Pretreat patients with volume prior to unclamping•

Question 71

_{AORTIC UNCLAMPING}

Hemodynamic Changes With Aortic Unclamping

Answer 71

↓ Myocardial contractility

↓ Arterial blood pressure

↑ Pulmonary artery pressure

↓ Central venous pressure

↓ Venous return

↓ Cardiac output

Decreased myocardial blood flow would be a late symptom of the initial hypotension and reduced SVR that occurs

Question 72

_{AORTIC UNCLAMPING}

Metabolic Changes With Aortic Unclamping

Answer 72

↑ Total body oxygen consumption

↑ Lactate

↓ Mixed venous oxygen saturation

↑ Prostaglandins

↑ Activated complement

↑ Myocardial-depressant factor(s)

↓ Temperature

Metabolic acidosis

Question 73

_{AORTIC UNCLAMPING}

Therapeutic Interventions With Aortic Unclamping

Answer 73

↓ Inhaled anesthetics

↓ Vasodilators

↑ Fluid administration

↑ Vasoconstrictor drugs

• Reapply cross-clamp for severe hypotension
• Consider mannitol
• Consider sodium bicarbonate

Question 74

_{SPINAL CORD ISCHEMIA/PARAPLEGIA}

Incidences of paraplegia for thoracic aneurysm, for thoracoabdominal repair, and for dissecting TAA repair are

Answer 74

0-10% for thoracic aneurysm

10-20% for thoracoabdominal repair

40% for dissecting TAA repair

Question 75

_{SPINAL CORD ISCHEMIA/PARAPLEGIA}

Blood supply to the spinal cord

Answer 75

25% from two Posterior arteries

Posterior arteries supply the sensory tract of spinal cord

75% from one anterior artery

Anterior arteries supply motor tract of spinal cord

Question 76

_{SPINAL CORD ISCHEMIA/PARAPLEGIA}

Which artery supplies lower 2/3 of spinal blood supply?

Answer 76

Artery of Adamkiewics

This is an anterior artery, meaning that it supplies the motor tract

Has no definition to make it stand out from other radicular or lumbar arteries

Reason why even low aortic aneurysm repairs like infrarenal are associated with 0.25% incidence of paraplegia

Exclusion from circulation => spinal cord ischemia and paralysis

Question 77

_{SPINAL CORD ISCHEMIA/PARAPLEGIA}

Preventative Measures

Answer 77

Reimplantation of intercostal arteries

Shortened clamp time

^{(the two above are both controlled by the surgeon)}

CSF drainage***

^{(Use is controversial b/c hasn’t been proven to reduce paraplegia - CSF drainage, although controversial, by way of a lumbar catheter. You will see this still being widely used)}

Adequate MAP

Normal glucose ranges

Epidural/spinal cord cooling

^{(can be achieved w/ or w/o CPB)}

Shunts and Bypasses

^{(Only beneficial with clamp times >30 minutes)}

Somatosensory evoked potentials and/or Motor evoked potentials

^{(Used intra-op)}

Question 78

_{SPINAL CORD ISCHEMIA/PARAPLEGIA}

SSEP monitoring alone is controvertial - why?

Answer 78

only monitors lateral and posterior sensory colum

Ischemia can still occur despite normal SSEPs signals

Question 79

_{SPINAL CORD ISCHEMIA/PARAPLEGIA}

MEP monitoring has been used successfully to monitor the anterior colum. During Ao clamping, are frequently are MEPs moitored?

Answer 79

Every minute

Reduction of 25% from baseline MEPs is indicative of spinal cord ischemia

Question 80

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

T/F: No single technique is superior

Answer 80

True

Each pt situation is unique

Question 81

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Overall goal is:

Answer 81

Balanced anesthesia

that produces the best hemodynamic and metabolic stability,

w/ optimal post-op pain control

Question 82

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Prevent hypertensive response - why?

Answer 82

HTN => stress on aneurysm => rupture

Question 83

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Prevent tachycardia to

Answer 83

Reduce myocardial O2 demand

Question 84

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

•Consider extubation only after

Answer 84

hemodynamic and metabolic stability

Question 85

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

T/F: Postoperative pain control is important

Answer 85

True

Question 86

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Appropriate induction technique to to prevent HTN and attenuate response to DL:

Answer 86

Moderate-dose narcotic technique

in combo with Propofol or Etomidate

Esmolol, NTG, and Phenylephrine available for bolusing

Placement of DLT w/ fiber optic verification

Question 87

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Maintenance

Answer 87

Epidural/General combined

Epidural prevent stress response + help reduce post-op pain

Consider TIVA if MEP monitoring used

Maintain CO and BP and preoperative levels

Temperature control

^{(All fluid and blood products should be warmed + upper body forced-air warmer applied)}

Do not use lower-body warmer during AoX

Heparin administration

Question 88

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Do not use lower-body warmer during AoX - why?

Answer 88

Could increase injury to ischemic tissue by increasing their metabolic demands

Question 89

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Emergence - Extubation:

Answer 89

Usually in ICU after hemodynamically stable

Consider exchanging double lumen tube for single lumen ETT

Question 90

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

COMMON INTRAOPERATIVE PROBLEMS after open TAA repair

Answer 90

• Hypertension and tachycardia
• Massive blood loss
• Coagulopathy
• Persistent acidosis
• Difficult ventilation
• Hypotension
• Low cardiac output
• Arrhythmias
• Hypothermia
• Oliguria/renal insufficiency

Question 91

_{ANESTHETIC TECHNIQUE FOR OPEN ANEYRUSM REPAIR}

Mortality and Morbidity after open repair

Answer 91

Despite advancements in surgical and anesthetic techniques, morbidity and mortality after surgery continue to be an issue

Pts who undergo extensive reapir have a higher incidence of peri-op risks

Mortality rates range from 5% to 14%

Question 92

_{EMERGENCY AORTIC SURGERY}

most common cause of emergency surgery is:

Answer 92

Leaking or ruptured aortic aneurysm

Question 93

_{EMERGENCY AORTIC SURGERY}

Ruptured aneurysm most common in which pts?

Answer 93

Patients > 80 years of age

10 x more likely Men > female

High incidence of mortality

^{(Swedish study 41% arrival in ER alive, nearly 100% of them died)}

Question 94

_{EMERGENCY AORTIC SURGERY​}

AAA most often ruptures where?

Answer 94

into Retroperitoneal space

This can allow for a life-saving tamponade

These pts will often present w/ pain but no frank shock

Question 95

_{EMERGENCY AORTIC SURGERY​}

25% of AAA rupture into peritoneal cavity; These are a/w:

Answer 95

almost certain exsanguination

Question 96

_{EMERGENCY AORTIC SURGERY​​}

AAA Symptoms:

Answer 96

Pain in neck, abdomen, and back

Hypotension and fainting/collapse

Absence of hypotension does not rule out rupture

Expanding abdominal mass

Question 97

_{EMERGENCY AORTIC SURGERY​​}

T/F: Absence of hypotension w/ AAA presentation does not rule out rupture

Answer 97

True

Question 98

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

The goal for EMERGENCY AORTIC SURGERY is

Answer 98

Rapid assessment

Unless unconscious or unable to protect airway

Question 99

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

Great care should be used to avoid bucking, coughing and HTN - why?

Answer 99

These increase the risk for exanguination

Question 100

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

What’s the most immediate priority

Answer 100

Placement of large-bore IV for volume and blood

Followed by an arterial line insertion

(consider bilateral radial arterial line, why?

Question 101

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

Consider bilateral radial arterial lines, why?

Answer 101

To monitor BP and thus perfusion to both carotid arteries

Impaired perfusion to brachiocephaic artery => low BP in right arm

Impaired perfusion to left subclavian and potentially left common carotid => low BP in left arm

Discrepencies btw R. and L.-side BPs

Question 102

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

Resuscitation product

Answer 102

Type-specific cross-matched blood (preferred)

If not available, Type-specific non-cross-matched blood should be used

Last resort, O-neg blood

If no blood, use crystalloids and colloids until they are

Question 103

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

Goad HCT

Answer 103

Goad HCT of 30

With maintenance of normal coagulation and normal-high filling pressures

Question 104

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

Induction technique

Answer 104

Rapid sequence induction

Small doses of etomidate and Succinylcholine

Question 105

_{EMERGENCY AORTIC SURGERY ANESTHETIC MANAGEMENT}

Intervention If rupture suscpected

Answer 105

Rapid control of the aorta by means of Ao X

If the pt becomes unstable, the surgical team will be prepping the abdomen during volume resuscitation or even during induction

Question 106

_{ENDOVASCULAR REPAIR OF AORTIC ANEURISMS}

EVAR: Endovascular aneurysm repair for AAA treatment

Answer 106

Becoming a standard approach to treat thoracic and abdominal aortic aneurysm

TEVAR: Thoracic endovascular aneurysm repair

Question 107

_{ENDOVASCULAR REPAIR OF AORTIC ANEURISMS}

First endovascular repair done in

Answer 107

1990 By Dr. Parodi

Question 108

_{ENDOVASCULAR REPAIR OF AORTIC ANEURISMS}

Studies comparing open approaches to endovascular approaches show:

Answer 108

Favorable Short term outcomes better in endovascular groups when compared to open technique

+ Shorter recovery times

+ Absence of abdominal incision

+ Avoidance of AoX

+ Reduced 30-day mortality and less complication (EVAR groups)

+ Reduced perioperative M&M compared with open technique

Long term M&M (>2 years) fail to show significant difference

Decision regarding the optimal method for aneurysm repair remains uncertain until the long-term outcomes for the EVAR procedures are more clearly established

Question 109

_{ENDOVASCULAR REPAIR OF AORTIC ANEURISMS}

•Vascular access achieved through

Answer 109

Bilateral groing incisions

Expose the femoral vessels (arteries)

Question 110

_{ENDOVASCULAR REPAIR OF AORTIC ANEURISMS}

Fluoroscopy:

Answer 110

Defines the aortic anatomy

Fluoroscopy guidance used throughout procedure

Question 111

_{ENDOVASCULAR REPAIR OF AORTIC ANEURISMS}

Heparin:

Answer 111

Patient is heparinized

(100 units/kg; goal ACT >200 seconds)

Question 112

_{ENDOVASCULAR REPAIR OF AORTIC ANEURISMS}

Endovascular stent

Answer 112

Endovascular stent made of synthetic material collapsed and stored in delivery device, that once positionned in the aorta, is deployed

The Endovascular stent covers the entire aneurysm, preventing blood flow from entering aneurysmal sac

Question 113

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

EVAR procedures can be performed using:

Answer 113

Local anesthesia and MAC

Neuraxial regional anesthesia or

General anesthesia

(No current RCT compares the anesthetic techniques for EVAR, however some studies suggest that local or regional anesthesia have the least complications)

Question 114

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Anesthetic goals are:

Answer 114

Motionless field

Adequate intravascular volume to reduce risk of renal injury (from large amount of contrast dye

Anticoagulation management

Control of blood pressure (w/ ability to increase or decrease depending on the time of the procedure)

Temperature control

Question 115

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Standard monitors

Answer 115

_{[Similar to open reapair]}

5-lead EKG

SpO2

Right radial arterial line

^{(if there is any concerns that the stent will cover the left subclavian artery)}

Central venous access

TEE

CSF drainage

Question 116

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Local anesthesia use for:

Answer 116

Skin infiltration with local anesthetic

Possible ilioinguinal or iliohypogastric nerve block

Bilateral TAP blocks have also been successfully used

MAC used as adjunct

Concomitant administration of short-acting agents to provide sedation, analgesia, and/or anxiolysis

Question 117

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Effect Regional neuraxial anesthesia technique would include:

Answer 117

Single dose spinal, continuous spinal, or epidural

Question 118

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Goal of Regional neuraxial anesthesia

Answer 118

Provide regional anesthesia from T6-L3 that lasts 3-4 hours

Question 119

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Concern w/ Regional neuraxial anesthesia

Answer 119

Longer procedure (> 3-4 hours) + MAC as adjunct to sedation

GETA would have to be considered

Question 120

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

General anesthesia is deal for:

Answer 120

Patients with complex repairs

for which conversion to open technique more likely

Question 121

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Primary goal of General anesthesia

Answer 121

Avoidance of significant fluctuation in blood pressure

b/c hypotension acn cause cerebro or mycardial ischemia, esp. in pts w/ CAD

HTN can rupture the aneurysm

Balanced anesthetic technique is recommended, w/ supplemental short-acting narcotic use

Early extubation desired

Minimal analgesia requirements

Question 122

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Induction Accomplished with which agents

Answer 122

Short-acting agents, Propofol or Etomidate

Give slowly to avoid significant fluctuations in BP

Low-dose short-acting opioid use, b/c these pts are typically extubated after the procedure

May consider using double lumen tube, in the event that one-lung ventilation is required

Question 123

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Maintenance could be chieved with which agents

Answer 123

Volatile anesthetic or TIVA

depending on if nuro monitoring for spinal cord ischemia is used

Question 124

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Maintenance - Graft deployment => be aware of

Answer 124

Distal migration of stent

Question 125

_{ANESTHETIC GOALS FOR EVAR PROCEDURES}

Emergence

Answer 125

Early extubation in ICU is desirable

Exchange DLT for SLT at end of procedure prior to transporting to the ICU

Controlled extubation, avoidance of coughing or straining

Question 126

_{ANESTHESIA FOR EVAR PROCEDURES}

Considerations

Answer 126

Proximal graft deployment

^{(Newer generation graft have reduce graft migration during deployment - Still a concern - Prevention would be lower SBP < 100 mmHg per surgeon - TEE could be used to ensure proper postitioning of graft)}

Spinal cord ischemia

^{(Spinal cord ischemia and paraplegia are recognized complications of EVAR, esp. those involving the thoracic aorta, w/ an incidence as high as 8% - post-op hypotension can increase this risk - It’s important to have strick control of the BP)}

Rapid conversion to general anesthetic

^{(Must stay vigilent of the need to convert to GETA - Must always be prepared for the possibility)}

Hypothermia

^{(Hypothermia can impair coagulation - This is usually cpmbated by warming devices and administration of warmed IV fluids)}

Blood loss can be occult or overt

^{(Pay close attention to hypotension that is unresponsive to treatment)}

Renal injury

^{(Can occur either d/t to the occlusion of the renal artery by the graft, or by the large volume of contrast dye during fluoroscopy - Strategies to reduce the incidence of this include maintaining adequate intravascular volume)}

Aortic rupture

Endoleak

^{(inability to completely occlude aneurysmal sac from arterial blood flow)}

Question 127

_{ANESTHESIA FOR EVAR PROCEDURES}

Proximal graft deployment

Answer 127

Newer generation graft have reduce graft migration during deployment

Still a concern

Prevention would be lower SBP < 100 mmHg per surgeon

TEE could be used to ensure proper postitioning of graft

Question 128

_{ANESTHESIA FOR EVAR PROCEDURES}

Spinal cord ischemia

Answer 128

(Spinal cord ischemia and paraplegia are recognized complications of EVAR, esp. those involving the thoracic aorta, w/ an incidence as high as 8% - post-op hypotension can increase this risk - It’s important to have strick control of the BP)

Question 129

_{ANESTHESIA FOR EVAR PROCEDURES}

Rapid conversion to general anesthetic

Answer 129

(Must stay vigilent of the need to convert to GETA - Must always be prepared for the possibility)

Question 130

_{ANESTHESIA FOR EVAR PROCEDURES}

Hypothermia

Answer 130

Hypothermia can impair coagulation

This is usually cpmbated by warming devices and administration of warmed IV fluids

Question 131

_{ANESTHESIA FOR EVAR PROCEDURES}

Blood loss can be occult or overt

Answer 131

Pay close attention to hypotension that is unresponsive to treatment

Question 132

_{ANESTHESIA FOR EVAR PROCEDURES}

Renal injury

Answer 132

Can occur either d/t to the occlusion of the renal artery by the graft, or by the large volume of contrast dye during fluoroscopy

Strategies to reduce the incidence of this include maintaining adequate intravascular volume

Question 133

_{ANESTHESIA FOR EVAR PROCEDURES}

Endoleak

Answer 133

inability to completely occlude aneurysmal sac from arterial blood flow