Vascular Surgery Flashcards
What is the Most Common Peripheral Vascular Occlusive Disease?
Atherosclerosis
The mortality rate in patients with vascular disease is ___ X higher than in
the general population
The mortality rate in patients with vascular disease is 2-6 X higher than in the general population
Surgical Therapies for PVD
Transluminal Angioplasty
Endarterectomy
Thrombectomy
Endovascular Stenting
Arterial Bypass
What is the Number 1 Complication of any Vascular Procedure?
Myocardial Infarction
What is the Number 2 Complication of Vascular Surgery?
Stroke
Vascular surgery patients are known to be at elevated risk of
perioperative ______
Vascular surgery patients are known to be at elevated risk of
perioperative MACE
What are the 3 RF associated with PVD?
DM, Tobacco use and HLD
Major Ppen Vascular Cases can be associated with significant fluctuations in ______, _______, _________, _______, & ______
Major Ppen Vascular Cases can be associated with significant fluctuations in ______, _______, _________, _______, & ______
Fluid Volumes, Cardiac Filling Pressures, Systemic Blood Pressures, HR and Thrombogenicity
A careful history must be taken to define the extent of any diagnosed ASCVD & to screen for any undiagnosed concurrent disease (e.g., _______ , __________, or ________ or __________
_________)
A careful history must be taken to define the extent of any
diagnosed ASCVD & to screen for any undiagnosed concurrent
disease (e.g., angina or equivalent, TIA, or mesenteric or peripheral
ischemia)
Physical examination should evaluate for any evidence of end
organ involvement (e.g., __________,
______, or
________) or cardiovascular decompensation
(e.g., _______,
___________,
________________,
______, _
______, or
_________)
Physical examination should evaluate for any evidence of end
organ involvement (e.g., diminished pulses,
S4 gallop,
or residual
deficit from previous stroke) or cardiovascular decompensation
(e.g., new or worsened murmur,
jugular venous distention, third heart sound on cardiac auscultation,
rales,
shortness of breath,
or
peripheral edema)
What Labs or Tests would you order Preop?
CBC– if Blood loss, Anemia, and platelete count
Coagulation– If patient is on anticoagulants or regional is anticipated
Chemistry– ↑ risk of underlying renal insufficiency
12 lead EKG– Increased risk of MACE Done within 1 month
Ecco if previous LV dysfunction
______ are recommended in patients at high risk for MI
β-BLOCKERS recommended in patients at high risk for MI
When should B Blockers be started in vascular surgery patients?
Days to weeks before surgery
Ideal HR for patients undergoing Vascular surgery ?
HR should be 50-60 BPM to ↓ Cardiac Stress
A _______ should be instituted 30 days prior to the surgical
procedure & continued throughout the postoperative period
A STATIN should be instituted 30 days prior to the surgical
procedure & continued throughout the postoperative period
STATINS have Cardioprotective effectrs as the
1.
2.
3.
4.
5.
Statins:
1. ↓ Vascular Inflammation
2. ↓ the incidence of thrombogenesis
3. ↑ Nitric Oxide Bioavailability
4. Stabilize atherosclerotic Plaques
5. ↓ Lipid Concentration
According to the Poise trial Aspirin has what perioperative effect / Consequence?
Aspirin does not prevent MI and does ont alter the risk of Periopertative cardiovascular event
However does ↑ the risk of major bleeding event
Indication for Carotid Endartectomy (4)
- TIA Associated with Ipsilateral Severe Carotid Stenosis
- Severe Ipsilateral Stenosis in patient with incomplete Stroke
- 30-70 % occlusion in a patient with Ipsilateral symptoms
- Historically– Asymptomatic Stenosis Lesions >60 % would be recommended for CEA, now they are stented
Risk Factors for perioperative Mortality of CEA (6)
- Age >75
- Symptomatic Lesions
- Uncontrolled HTN
- Angina
- Carotid Thrombus
- Occlusions near the carotid Siphon
What is the most likely site of a CEA?
Bifurcation of the Carotid Artery with the proximal internal carotid involvement
Anatomical Structures near the carotid dissection (5)
- Hypoglossal Nerves
- Vagus Nerve
- RLN
- Mandibular Branch of Facial nerve
- Glossopharyngeal nerve
Chronic HTN shifts the Cerebral autoregulatory curve which way? meaning what?
Shifts to the right
CBF becomes BP dependant and narrows range for ideal flow.
Profound Hypocarbia Causes Cerebral Vascular _______. Causing ___ in CBF
Profound Hypocarbia Causes Cerebral Vascular CONSTRICTION. Causing ↓ in CBF
______ Occurs with Hypercarbia as it leads to Cerebral Vascular ________ in Cerebral Vessels
___Cerebral Steal__ Occurs with Hypercarbia as it leads to Cerebral Vascular __Dilation___ in Cerebral Vessels
Inhalation agents __ CBF d/t _______ in a dose dependant manner
Inhalation agents ↑ CBF due to cerebral vascular dilation in a
dose-dependent fashion
Anesthetic Agents Except ______ ↓ CMRO2
Anesthetic Agents Except ____Ketamine__ ↓ CMRO2
Normal CBF
– 50 mL/100g/ min
Each 100 ml of blood contains ___ mL of O2
20 mL of O2
CMRO2 in brain is ____
3-5 ml/100g/min AVG 3.5
Ischemia is apparent on EEG at CBF of ________
20 ml/100g/min
Neuronal Destruction occurs at CBF of _______
10 mL/100g/min
Carotid Circulation supplies _______% of the Brain
other % is the ______
Carotid Circulation supplies __80-90%__% of the Brain
other % is the __Vertebral Artery___
1 Goal for Anesthesia during CEA?
Avoid Hemodynnamic extremes
Extreme Hypocarbia causes a _____ Shift in the Oxyhemoglobin curve
Extreme Hypocarbia causes a ___Left__ Shift in the Oxyhemoglobin curve
What is Luxury perfusion?
Diseased Blood vessels are maximally dialate and will not constrict or dilate further. CO2 has little effect on their flow
Increased CBF during normal state
Intracerebral Steal Syndrome
↑ in PaCCO2 causes ____ in normal vessels and _____ of blood from _____ vessels
Intracerebral Steal Syndrome
↑ in PaCCO2 causes _Dilation__ in normal vessels and __Shunting___ of blood from __diseased___ vessels
Modalities to protect the brain
(4)
- Hypothermia (low normal)
- Aggressive Glucose Control (Avoid Glucose Solutions)
- ↓ CMRO2
- Shunts (During Cross Clamping)
Pitfalls of Carotid Shunt Placement (2)
Potential traumatic injury to the distal internal carotid artery intimate
Potential for embolization of the atherosclerotic debris or air
Problems with Shunts
(9)
- Duslodgement of plaque or clot
- Air Embolism
- Kinking
- Shunt occlusion against Art Wall
- Dusruption of Distal Internal Carotid
- Patient may still get EEG Changes
- Shunt may impair surgical access
- only beneficial if the cause is low flow
- 65-95 % of neurologic deficits during CRA may be thromboembolic
Ways to monitor Cerebral Perfusion
EEG, SSEP, Cerebral Pulseox, Transcranial Doppeler, Awake patient, Direct Xenon Cerbral blood flow measure, Stump Pressure
Stump pressure normal and extreme values
Normal- 40
Extreme Values <25 >60
_______ – not recommended to allow for rapid neuro assessment postop
__Midazolam__ – not recommended to allow for rapid neuro assessment postop
Limit fluid to a max of _____ mL/kg in 2 hour
10 mL/kg
Benefits of LA in CEA
↓ Opioid use
↓ Baroreceptor mediated Bradycardia from carotid bodies
BP goal before and after carotid Cross clamping
Normotension
BP goal During cross clamp
20% above baseline
Average cross clamping time
30 minutes
Baroreceptor Reflex S/s
Sudden Bradycardia and hyptension
Sudden Bradycardia and hypotension during CEA Treatment
Surgeon injects 1 % lidocain to the bifurcation of the carotid sinus
This blocks sodium channels so no conduction from the nerves to the brain and no drop in HR
This can result in post op Hypertension
How much heparin is given before cross clamping
50-100 u/kg
When is an ACT drawn
3 minutes and every 30 minutes thereafter
How much protamine is given
50 - 150 mg given SLOWLY
What level is necessary for Regional Anesthesia
C2-C4 Dermatome blocked
Deep or superficial Cervical block
Advantages of Regional anesthesia for CEA (5)
Stable BP
Inexpensive and easy
Avoidance of tracheal intubation
Avoidance of negative Inotropic anesthetic agents
Disadvantage for Regional for CEA (3)
1.Risk of Laryngeal nerve paralysis and phrenic nerve palsy
2. Requires highly cooperative patient
3. Unpredictable risk of sudden onset agitation and poor
Respiratory Complications of CEA
Recurrent Laryngeal / Hypoglossal injury d/t neck hematoma or deficient crotid body function
Tension Pneumothorax @ apex
Risk Factors for Hematoma formation (2)
Failure to reverse Heparin
Remaining intubated post op
What is the result of Cerebral hyperperfusion Syndrome? and what increases the risk?
Cerebral Edema
HTN ↑ risk
Who does Cerebral Hyperperfusion synrome happen in mostly?
Those with a contralateral CEA w/i 3 months and a 2nd CEA on the ipsilateral side
ACT for Carotid Angioplasty and Stenting
> 250 seonds
Sedation for Carotid Angioplsty and stenting
Minimal, Patient needs to be arousable and responsive
RF for AAA (7)
- Advanced Age (50-80)
- Male > Female
- Family Hx
- Smoking ↑ 5x
- CAD, HTN, PVD, ↑ Cholesterol
- COPD
- Caucasian
Contraindication for Elective repair
- Interactable Angina
- Recent MI
- Severe Pulmonary dysfunction
- Chronic Renal Insufficiency
Law of Laplace
T (Wall Tension)= P (Transmural Pressure) x r (Vessel Radius)
↑ risk of rupture > ____cm
Surgical repair > ____cm or growth >
____-____ cm/year
↑ risk of rupture > 5cm
Surgical repair > 5.5cm or growth >
0.6-0.8 cm/year
Goals of AAA
Optimization of Myocardial O2 Supple and demand
Modification of cardiac RF
Done with B blockers and statins
What is the most important patient preperation to enhance cardiac function
Fluid loading
restoration of intravascular volume
_______ is an ever-present threat, therefore the availability of blood & blood products should be ensured
__Massive hemorrhage__ is an ever-present threat, therefore the availability of blood & blood products should be ensured
Hypovolemia in AAA patients preop is caused by
Radiographic dye studies and bowel prep
Heparin ____ units/kg are administered 5 minutes before aortic cross clamping
ACT Level Required
100-300 units/kg
ACT >400
Main Anesthetic goals of AAA repair
Keep Patient Warm
Keep HR Slow
Avoid Anemia
Prevent HTN – Especially prior to clamping
Classic Triad of AAA
1.Severe Back pain
2. Altered Mental State d/t Hypotension
3. Apulsatile abdominal mass
Emergency AAA Repair Priorities
Treat Hypothermia
Administer Ca d/t lack of citrate metabolism d.t lack of liver flow
Vasopresin for catecholamine depletion
Primary goal of AAA rupture
Control of blood loss and reversal of hypotension
Then preservation of hte myocrdial function
Directly related response to Aortic Cross-Clamping
Location of clamp (Most common is infrarenal)
Intravscular Volume
Cardiac Reserve
Applcation of Aortic Cross ClampCreates _____
Central Hypervolemia
↓ Venous Capacity resulting from a shift in a large portion of blood volume proximal to the clamp and increasing venous return
Removal of Arotic cross clamp creates ____
Central Hypovolemia–Large ↓ in BP
Venous capacity is restored blood shifts back to lower body below clamp capillary beds leak decreasing intravascular volume and ↓ venous return
CV Canges with Cross Clamp
HR-
CO-
Above Clamp?
Below Clamp?
HTN above the cross clamp
Hypotension below cross clamp
Due to ↑ SVR aortic impedence and after load
Cardiac Output ↓ or remains
HR remains unchanged
Hemodynamic Changes with Cross Clamp
Increased (6)
Art BP Above Clamp
Segmental Wall motion abnormalities
Left Ventricular Wall Tension (↑ Afterload)
PAOP
CVP
CA Blood Flow (↑ Demand/Adenosine)
Myocardial O2 Demand – ↑ Afterload and ↑ Preload & Conractility
Hemodynamic Changes
Decreased… (4)
Art BP Below Clamp
EF
CO
Renal Blood Flow
Metabolic Changes
Increased… (3)
Mixed Venous O2
Epi and Norepi
Respiratory Alk and Met Acidosis
Metabolic Changes
Decreases …
total-Body O2 Consumption
Total Body CO2 Production
Total Body O2 Extraction
Fluid Shifts from ____ to ____ distal to clamp
and ____ to ____ proximal of Clamp
Fluid Shifts from __Iterstitial__ to _intravascular___ distal to clamp
and _intravascular___ to _interstitial___ proximal of Clamp
Hemodynamic Change– ↑ BP Above Clamp
Metabolic Change ↓ Total Body O2 Consumption
Intraop intervention
↓ Afterload–> Na Nitroprusside
Inhaled Anesthetics
Milrinone
Shunts and Aorta to Femorlal Bipass
Hemodynamic Change– ↓ in arterial BP below Clamp
Metabolic Change– ↓ in CO2 Production
Intraop Intervention:___
Nitroglycerin
Atrial to Femoral Bypass
Hemodynamic Changes– ↑ Wall Motion abnormalities and LV wall Tension
Metabolic Change: ↑ Mixed venous O2 Sat
Intraop Interventions:
renal Protection:
Fluid
Manitol
Lasix
Dopamine
N-Acetylcystein
renal Cold Perfusion
Effects of Cross Clamping on the Lungs
↑ PVR and PAP
Ischemia Generates Thromboxane Which …
↑ PAP,
induces Neutrophil Entrapment in lungs,
↑ Pulmonary permeability resulting in Pulnmonary edema and shunting
Aortic Cross Clamping of the kidneys results in _______, Which activates _______
Aortic Cross Clamping of the kidneys results in ___Hypoperfusion__, Which activates ___Renin- Angiotensin system__
What is the best way to effective protect the kidneys from ischemia?
Optimization of systemic hemodynamics including ciorculating blood volume
The major effect of Angiotensin II is ___
↑ in renal vascular resistance and sodium reabsorption
Directly (Proximal and tubular) and indirectly (by ↑ of aldosterone
____ reduces the degree of the ↓ in renal blood flow during cross clamp
__Manitol__ reduces the degree of the ↓ in renal blood flow during cross clamp
Paraplegia/Anterior Cord Syndrom is characterized by ____
loss of motor &
pinprick sensation but preservation of vibration &
proprioception
Where is the Artery of Adma owicz located?
Usually T8-T12 but can be L1-L2
Spinal Cord Ischemia Prevention Measures
Short Cross Clamp Times
Fast Surgery
Maintenance or normal Cardiac Function
Higher Perfusion Pressures
Monitoring SSEPs and MEPs
Ideal ICP for these Patients
10-12
Do not drain more than ____ mLs of CSF /hour. Risk for SAH
20 mL/hour
Hemodyamic Response to Unclamping
↓ Myocardail Contraction (Stunting), Arterial BP, CVP, Venous Return, CO, SVR and Preload
↑ in PAP
Unclamping Metabolic Changes
↓ in Mixed Venous O2 Sat, Temperature
↑ in O3 Consumption, Lactate, prostoglandins, Myocardial depressant Factors and aNetabolic Acidosis
Unclamping Intraop Interventions
↓ Anesthetic Depth
↓ Vasodilators
↑ Fluids
↑ Vasoconstrictors
Reapply Cross Clamp for Severe Hypotenion
Consider administration of mannitol and sodium bicarb
Whatcauses repurfusion syndrome?
Restoration of blood flow t tissues with ↑ inflammatory cell influx and cytotoxic substance wash out into central circulation
What is the severity of repurfusion syndrome dependant on?
Duration of clamping
Repurfusion syndrom results in: (6)
Myocardial Stunning and dysrhythmias
Hypotension
Acute Repiratory distress syndrome
Renal Failure
COmpartment syndrome
MODS
What influences the magnitude or Change in CO after Unclamping?
Intravascular Volume
Site
Duration of Clamp
Anesthetic Interventions to unclamping
↓ Anesthetic Depth
↓ Vasodilators and ↑ Constrictors
↑ Fluids
Fluid Load prior to unclamping
Reapply Clam and Gradual release
What Thoracic AAA Classification is this?
Debakey I
Stanford A
What Thoracic AAA Classification is this?
Debakey II
Stanford A
What Thoracic AAA Classification is this?
Debakey III
Stanford B
What Side A-Line for a Thoracic AAA repair
R Side
Anesthetic Management of AAA
Preload:
↓
Anesthetic Management of AAA
Afterload
↓ with Anesthetics, analgesics, and aerterial dilators
Keep Systolic <100-120
Anesthetic Management of AAA
Contractility
Maintain or ↑ Titrate Myocardial Depressant carefully
Advanctages to Endovascular Adbominal aortic repair
less Invasive
Shorter Hospital Stay
Lower Cost
No Aortic cross Clamping
↓ Embolic events
↓ blood loss
Reduce in stress response
Reduce organ dysfunction
↓ aortic interruption
↓ postop pain
Disadvantages tot Endovascular abdominal aortic repair
Endoleak
Graft Thrombosis
Ggraft migration
Graft Rupture
Graft infection
iliac artery rupture
Lower Extremity ischemia
Late AAA rupture
No long term all cause moratality or quality of life advantage for evar
ACT for Endovascular Abdominal Aortic Repair
ACT >200
What is the critical phase in endovascular thoracic aortic repair?
Device Deployment
ACT for Lower Extremity revascularization?
> 200 s
Regional Spinal Level for Lewer Extremity Revascularizatino?
T10
Repurfusion of Lwer Extremity causes release of ____, ____ and _____ that causes ____ and ______
Repurfusion of Lwer Extremity causes release of __Potassium__, __Cytokines__ and ___Metabolic acidosis__ that causes _Hypotension___ and ___Myocardial Depression__
Anesthesia for Vena Cava Filter?
Usually Local or MAC with light sedation
TIPS Procedure
______ or ____ within the first 6 months
TIPS Procedure
___Reocclusion___ or __thrombosis__ within the first 6 months
What is the most painful part of a TIPs procedure?
Balloon Dilation of the tract
Anesthesia considerations for TIPs procedure
RSI for Ascites
Coagulopathy
Hyperdynamic circulation
metabolism of drugs
respiratory alkalosis
Hemorrhage risk
Indications of Radiofrequency Ablation therapy for varicose veins
Symptomatic Superficial insufficiency of veins >3 mm that is refractory for those with compression stockings >18 yo
Contraindications for Radiofrequency Ablation of VV
(7)
- INcompetent superficial vein diameter <2mm
- Hx of extensive DVT in the same leg
- Active superficial DVT in the same vein
- History of prior surgical or endovenous treatment of the same leg
- Pregnancy
Known Malignancy - Overall poor health frail immobile
- Known bleeding or clotting disorders
