Vascular PP Flashcards
2 aspects that the extent of perioperative monitoring should be based on?
type of surgery and presence of coexisting disease
3 ways to assess cardiac function in vascular surgery patients?
TEE, EKG, PA cath
Does PAC monitoring affect length of stay or mortality in vascular patients?
no
When comparing vascular patients who had a PA cath versus those who did not, the PA cath group had higher rates of what 3 complications?
pulmonary embolism, pulmonary infarction, and hemorrhage
What procedures warrant routine use of PACs according to the ASA?
none
Patients with HTN or angiopathology rely on what to perfuse their vital organs>
increased mean arterial pressures
Patients with HTN or angiopathology require lower or higher pressures to maintain autoregulation?
higher
What is the most common cause of occlusive disease in arteries of lower extremities?
atherosclerosis
The short and sweet 3 step pathophysiology summary of how plaques affect arteries?
- plaque formation 2. thrombosis 3. aneurysm formation
4 symtpoms associated with peripheral occlusive disease?
gangrene, impotence, ulcers, claudication
Plaque is made up of what substances?
cholesterol, fat, Ca, fibrin, cellular waste products
Mortality rates for PVD at 5 years and 10 years, respectively?
30%; 70%
The extent of disability in PVD patients is influenced?
collateral blood flow
What is responsible for activating the clotting system in PVD?
inflammatory process
Target heart rate for beta blocker therapy in PVD patients?
50-60
Beta blocker therapy is recommended for PVD patients at risk for what 2 things?
MI, ischemia
5 effects on the pulmonary system that epidurals have?
Decreased effect on FVC, FEV1, and PEFR, Decreases ventilation perfusion mismatch, Improves atrioventricular oxygen differentiation, Decreases pulmonary postoperative complications, Decreased incidence of thromboembolism
2 effects that epidurals have on the renal system?
- Increases blood flow in the renal cortex
* Decreases renovascular constriction
2 effects that epidurals have in the geriatric population?
decreased stress and improved post op mental function
In regards to extubation and pain control how does epidural anesthesia affect those 2?
earlier extubation and improved pain control
What effects does epidural anesthesia have on the heart?
Decreases MVO2 demand & afterload, increases endocardial blood flow at ischemic zones, increased hemodynamic stability (?), Decreases GA medication usage, improves blood flow to lower extremities
7 things inhibited by epidurals?
surgical stress response, epinephrine & cortisol release (not sure if good or bad), hyperglycemia (good), lymphopenia, inflammatory mediator release, nitrogen sparing, blocks sympathetic tone
3 risks possible when having surgery on the aorta?
large intraop blood loss, renal failure, paralysis
An EF less than what percentage proves to be risky when having aortic surgery?
30
3 screening tools to diagnose AAA?
MRI, CT, ultrasound
Primary goal of preoperative period for AAA?
restore intravascular volume/fluid load
Blood products to have available for AAA surgery?
PRBC x 2, FFP, platelets
When does heparinization occur during AAA repair?
before occlusion
Renal prophylaxis during AAA repair can be completed with?
mannitol
Abdominal aortic aneurysm repair can be done using which 2 approaches?
transperitoneal or anterolateral
For an abdominal aortic aneurysm repair, what are the 3 locations the clamp can be placed?
supraceliac, suprarenal, infrarenal
There is less effect on LV afterload when the clamp is placed where in AAA surgery?
farther distally
The aortic cross clamp causes what to happen to BP above and below clamp?
above- HTN; below- hypotension
What happens to MAP and SVR during aortic cross clamping? What happens to PAW?
increase; increase PAW
What affect does aortic cross clamping have on afterload and wall tension?
increases both
Why may aortic cross clamping cause issues in the ischemic heart?
because aortic cross clamping increases afterload and wall tension
The hemodynamic effects of aortic cross-clamping depend on what 3 things?
the application site along the aorta, the patient’s preoperative cardiac reserve, and the patient’s intravascular volume
Most common site for aortic cross clamping?
infrarenal
What two systems are involved with aortic cross clamping?
SNS, RAAS
5 metabolic changes which occur from aortic cross clamping?
increased lactic acid, release of arachidonic acid, thromboxane A2, cyclo oxygenase inhibitors, increased epi and norepi levels
How do beta blockers help w the metabolic changes associated with aortic cross clamping?
as a result of aortic cross clamping, epinephrine and norepinephrine release are increased and stimulate myocardial β1-receptors that can increase heart rate and myocardial oxygen demand
This is a metabolic change associated with the decrease in myocardial contractility and cardiac output during aortic cross clamping?
thromboxane A2
5 symptoms common with mesenteric traction syndrome?
decreases in blood pressure and SVR, tachycardia, increased cardiac output, and facial flushing
These mediators are thought to be responsible for the tachycardia, elevated temp, leukocytosis, and fluid sequesteration during surgery?
TNF, IL-6, catecholamines, cortisol
The hemodynamic instability that may ensue after the release of an aortic cross-clamp is called?
declamping shock syndrome
What happens to the SVR, vessel tone, afterload, preload, CO, and myocardial tone in declamping shock syndrome?
all decrease and the vessel tone dilates and blood is directed to the dilated vasculature
This is paramount in providing circulatory stability before release of the aortic clamp?
Restoration of circulating blood volume
What three things influence the magnitude of circulatory instability after undoing the aortic cross clamp?
site and duration of cross-clamp application, gradual release of the clamp
What does decreased myocardial contractility do to total body oxygen consumption? What can the CRNA do to counteract decreased myocardial contractility during AAA repair?
increase; decrease vasodilators
What does decreased CVP do to prostaglandin levels?
decrease
What is a major complication of clamping the thoracic aorta?
spinal cord ischemia and paraplegia
At what spinal level is the Artery of Adamkiewitcz located?
T8-L2
Where does the spinal cord receive its blood supply from?
vertebral arteries and thoracic and abdominal aorta
Classic deficit of spinal cord ischemia? These deficits are also commonly known as?
loss of motor function and pinprick sensation but preservation of vibration and proprioception; anterior spinal artery syndrome
There is an increased incidence of renal failure following aortic surgery associated with what 3 events?
emergency procedures, prolonged cross clamp period, prolonged hypotension
What is the dose of mannitol to infuse prior to cross clamping to preserve renal function?
0.5g/kg
What infusion can treat renal vascular HTN?
fendoldopam
5 indications for aortic surgery?
dissection, aneurysm, occlusive disease, trauma, coarctation
What are the 4 specific site lesions requiring aortic surgery?
ascending aorta, aortic arch, distal to left subclavian artery and above diaphragm, below diaphragm
The 6 etiologies of thoracic aortic aneurysms?
degenerative (arteriosclerotic), mechanical (dissection, trauma), connective tissue syndrome, inflammatory, anastomatic (postarteriotomy), infectious
A true aneurysm involves which layers, whereas a false aneurysm involves this layer?
true involves all, false involves only adventitia
Thoracic aneurysms are classified based on what three things?
location, shape, type
This type of aneurysm has a spindle shape and results in dilation of the aorta?
fusiform
These aneurysms are spherical dilations and are generally limited to only one segment of the vessel wall?
saccular
Aortic dissection is the result of a spontaneous tear within what layer that permits the flow of blood through a false passage along the longitudinal axis of the aorta?
intima
Thoracoabdominal aortic aneurysms (TAAA) are classified using the ___________ classification?
Crawford
A Type A Type I Aortic Dissection occurs where?
entire length of aorta
A Type A Type II Aortic Dissection occurs where?
ascending aorta
A Type B Aortic Dissection occurs where?
distal to subclavian artery
A Type A Aortic Dissection is also known as? A Type B Aortic Dissection is also known as?
proximal; distal
What can an aortic aneurysm do to the trachea or bronchus?
compression or deviation
What type of valve irregularity can an aortic aneurysm produce?
aortic regurgitation
Normal adult aorta is how many cm?
2-3 cm
Operative mortality rate of aortic aneursym? if leaking occurs?
2-5%; > 50%
What does a chest x ray show in aortic trauma?
wide mediastinum
Which artery is recommended for monitoring BPs for surgery on the ascending aorta?
left radial artery bc of proximity of inominate artery to where you put clamp
What is unique about the surgical technique for ascending aorta surgeries?
uses median sternotomy and cardiopulmonary bypass
A good drug to use during ascending aorta surgeries?
nitroprusside
Descending thoracic aorta: What approach is used if limited to descending aorta?
left thoracotomy
Descending thoracic aorta: what approach is used if the abdominal aorta is involved?
thoracoabdominal
Descending thoracic aorta: One or two lung ventilation?
one
Descending thoracic aorta: arterial pressures measured from which artery?
right radial
Descending thoracic aorta: where is aorta cross clamped?
above and below the lesion
Descending thoracic aorta: HD instability likely to occur following release of the cross clamp due to what 3 reasons?
abrupt decrease in afterload, bleeding, release of vasodilating acid metabolites
Descending thoracic aorta: 3 therapeutic considerations for releasing the cross clamp?
decrease anesthetic depth, volume load, partial or slow release of the cross clamp
Descending thoracic aorta: 3 good drugs to treat hypotension after releasing cross clamp?
CaCl, bicarb, vasopressors
Some early complications of thoracic aortic surgery?
MI, CHF, resp failure, paraplegia, embolism, bowel ischemia, renal failure, CVA, vocal cord paralysis, sexual dysfunction
Which artery is the guidewire threaded through for an EVAR repair?
femoral artery to iliac artery
When is heparin given during an EVAR?
prior to manipulation of catheter
Advantages of EVAR versus the open repair?
no aortic cross-clamping, improved hemodynamic stability, decreased incidence of embolic events, decreased blood loss, reduced stress response, decreased incidence of renal dysfunction, and decreased postoperative discomfort
Is local anesthesia versus general anesthesia more beneficial for patients undergoing EVAR?
no
Some factors contributing to morbidity during carotid endarterectomy?
operative timing, hyperglycemia, history of stroke, surgery w or w/out a shunt, ulcerative lesion, age
The greatest contribution to overall morbidity related to carotid endarterectomies is?
MI
How do you calculate cerebral perfusion pressure?
difference between MAP and ICP
During CEA, what plays a predominant role in regulating CPP?
MAP
When MAP is maintained between __ and __ CBF remains constant?
60-160
Chronic systemic hypertension shift the patient’s cerebral autoregulatory curve to which direction?
right
Why should MAP be higher during a CEA?
Chronic systemic hypertension shift the patient’s cerebral autoregulatory curve to the right so a higher MAP is required to maintain CPP
Normal CBF?
50mL/100 g/min
Neuronal function is generally maintained at CBF levels greater than?
25 mL/100 g/min
Cellular death occurs at CBF levels less than?
6 mL/100 g/min
Cerebral ischemia leads to disruption of autoregulation and therefore what does the vasculature do? Therefore the blood flow becomes dependant on?
dilate; pressure
What is the major objective during carotid artery revascularization?
maintain CBF and decrease cerebral ischemia
How can cerebral ischemia be prevented during CEA?
increasing collateral flow (placement of intraluminal shunt) or by decreasing cerebral metabolic requirements (pharmacologic adjunct)
4 interventions for preserving cerebral protection?
avoiding hyperglycemia, hemodilution, maintenance of normocarbia, and tight control of arterial blood pressure
What is the risk associated with shunting during a CEA?
shedding of debris in to cerebral vasculature
What medications should the patient receive prior to CEA?
all of his/her usual medications
Superficial and deep cervical plexus blocks block which nerves?
C2-C4
Advantages of superficial and deep cervical plexus blocks during CEA?
LOC, speech, contralat hand grip can be assessed and examined intraop
Disadvantages of superficial and deep cervical plexus blocks during CEA?
airway not secured, full cooperation of pt required
What is common for BP to do during carotid surgery?
HTN
What should the goal be for CO2 during CEA?
normocapnia
How should emergence and extubation be after a CEA?
smooth and uneventful
T/F: It has now been determined the incidence of stroke resulting from CAS is similar to the CEA results for all age
True
The most common complication associated with carotid artery stenting?
stroke
Some complications associated with carotid artery stenting?
MI, bradycardia, hypotension, stroke, Horner syndrome, cerebral hyperperfusion syndrome, carotid artery dissection/rupture
What does increased arterial BP above the clamp mean? And what is our intraoperative intervention?
decreased O2 consumption; nitro, milrinone, inhaled anesthetics (reduce afterload), shunt and aorta to fem bypass
What does decreased arterial BP below the clamp mean for us? And what is our intraoperative intervention?
Decreased total body CO2 production; reduce preload/nitroglycerin, atrial to femoral bypass
How will increased wall motion abnormalities and left ventricular wall tension be manifested during aortic surgery? And what is our intervention?
increased mixed venous O2 sat; renal protection/fluid admin, mannitol, lasix, dopamine, mucomyst, sodium bicarb
What does a decreased EF and CO mean for us during aorta surgery? What are interventions done to help w that?
decreased total body O2 extraction; hypothermia, decrease minute ventilation, sodium bicarb
What does decreased RBF do to catecholamine release?
increase
Acid base imbalance from increased pulmonary occlusion pressure?
respiratory alkalosis
Acid base imbalance from increased CVP?
metabolic acidosis
Vascular patients receiving what 3 types of surgery should be considered high risk for an ischemic event?
open AAA repair, visceral arteries, and lower leg revascularization,
In what 2 ways can coronary ischemia occur in vascular patients?
plaque becomes loose and subsequent vessel thrombosis or supply demand mismatch exacerbated by tachycardia and HTN
What is another contributing factor increasing cardiac risk in patients undergoing major arterial repair?
fluid shifts caused by blood loss and HTN
