Peripheral Vascular disease/Valvular disease Flashcards
1
Q
What is Peripheral Vascular disease?
What causes it?
A
- A compromised blood flow to the extremities
- Ankle-brachial index of less than 0.9
- Ratio of SBP in ankle vs SBP in brachial artery
- Causes:
- Atherosclerosis- most common
- arterial embolism
- vasculitis
2
Q
How prevalent is atherosclerosis?
A
- 2 million Americans are symptomatic
- associated with aging
- exceeds 70% in ppl over the age of 75
- increases with risk factors
3
Q
What are the risk factors of atherosclerosis?
A
- DM
- advanced age
- male gender
- ovesity and physical inactivity
- sedentary lifestyle
- essential HTN
- smoking
- dyslipidemia
- family Hx
4
Q
What are the signs and symptoms of atherosclerosis?
A
- Intermittent claudication (angina of the legs)- most common
- cool/cold feet to touch
- pain while laying flat and relieved by a sitting position
- loss ofpulses in legs or feet, pale color when legs are raised
- dependent rubor (redness)
- shiny skinn, loss of hair
- thickened toenail (fungal infections)
- Critical limb ischemia (rest pain)- lack of O2 to the limb/leg at rest
- associated with non-healing ulcers and gangrene
- most severe symptom
5
Q
What is the treatment for atherosclerosis?
A
- Identify and treat the risk factors
- exercise, lifestyle change, wt loss, smoking cessation
- lipid lowering therapy (statins)
- Vitamin C and E and Folate supplements
- Anti-platelet therapy
- Revascularization procedures
- amputation
6
Q
What
A
- After donor and recipient arteries are exposed, tunnel is created and graft is passed
- Graft may be saphenous vein or a prosthesis
- usually prosthesis b/c if one vein is so bad they need a graft, the saphenous vein probably isnt much better
- Heparine IV given (note time)
- Anastomosis are constructed
- Arteriogram to confirm adequate flow
- heparin not likely to be reversed b/c it is probably a small dose
7
Q
Pt with PVD has _____ greater risk of MI, stroke, and death
A
3-5x
These pts probably also have CAD
8
Q
What are the preferred anesthesia techniques for peripheral revascularization surgeries?
A
- Regional Anesthesia:
- increased graft blood flow
- less increase in SVR with cross-clamping
- postoperative pain relief
- less activation of the coagulation system
- Regional Vs General
- assess for coagulopathy
- If regional, spinal may be best to avoid hematoma
- No difference in cardiopulmonary complications btw RA and GA
- Significantly fewer graft occlusion complications with RA
9
Q
What should you consider for the anesthesia management of a peripheral revascularization surgery?
A
- Consider co-morbidities
- Medication Hx and impact on anesthesia delivery
- end organ perfusion and oxygenation- may want foley
- blood gases to not electrolyte and pH changes
- Cross clamp- heparin administration
- record time
- reversal?
10
Q
How should you monitor a pt during peripheral revascularization surgery?
A
- Pts typically have CAD, DM, HTN
- Make sure pt takes BBs and other chronic meds
- Art line
- CVP or catheter- to monitor intravascular volume
- EBL
- estimated third space
11
Q
What is the definition of Mitral Stenosis?
A
- Normal mitral valve orifice is 4-6 cm2
- Considered stenotic when the orifice is <1-1.5 cm2
- a mean left atrial pressure of about 25 mmHg is necessary to maintain an adequate resting cardiac output (normal 8-10)
12
Q
What is almost always the cause of mitral valve stenosis?
A
- Almost always caused by fusion of the mitral valve leaflets at the commissures during the healing process from rheumatic fever
13
Q
What is the root of the problem you are dealing with stenosis?
What is the root problem with regurgitation?
A
- Stenosis = pressure problem
- regurgitation = volume problem
14
Q
What is the pathophysiology of mitral stenosis
A
- Fusion of valves from rheumatic fever
- increased pressures in LA requires to move blood through the tiny mitral opening
- this causes LA enlargement
- LA enlargement predisposes to atrial fibrillation
- blood stasis in bil LA predisposes the formation of thrombi–this is why pts with mitral stenosis may be on chronic anticoagulation therapy
15
Q
What are the symptoms of Mitral valve stenosis?
A
- dyspnea on exertion when CO is increased
- Severe mitral stenosis leads to pulmonary hypertension and CHF
16
Q
What are the goals when managing the anesthesia of a pt with mitral stenosis?
A
- Goals: slow, tight, full
- Avoid tachycardia or rapid ventricular response rate during afib (slow)
- avoid marked increases in central blood volume that could be caused by over transfusion or head-down position
- Avoid drug-induced decreases in SVR (tight)
- Avoid events such as arterial hypoxia and/or hypoventialtion that may exacerbate pulmonary HTN and evoke right ventricular failure
17
Q
How should you induce a pt with Mitral stenosis?
A
- With drugs that are unlikely to increase HR (avoid ketamine) or abruptly decrease SVR
- Ex. etomidate with balanced technique
18
Q
How should you try to manage the maintenance of anesthesia in a pt with Mitral stenosis?
A
- Use drugs that have minimal affect on HR,SVR, PVR, and myocardial contractility
- may need BBs and CCBs, phenylephrine
- Monitoring:
- need for invasive monitoring depends on the complexity of the procedure and magnitude of impairment caused by MS
19
Q
What are the two factors associated with the development of Aortic stenosis?
A
- Aging- degeneration and calcification of the aortic leaflets
- incidence is increasing as population is aging
- Presence of a bicuspid aortic valve (BAV), which is a common congenital valve abnormality
- b/c of abnormal shape, fibrosis and calcification more likely
20
Q
What are the measurements that cause hemodynamically significant aortic stenosis?
What are the characteristic symptoms of AS?
A
- Aortic valve orifice area < 1 cm2 (normal 2.5-3.5 cm2)
- transvalvular pressure gradient >50 mmHg
- Symptoms
- angina in the absence of ischemic heart disease
- dyspnea on exertion
- syncope
21
Q
What are the goals when managing anesthesia for a patient with Aortic stenosis?
A
- Avoid any events that would further decrease CO
- Maintain NSR- properly times atrial contraction will produce an optimal LVEDV
- avoid bradycardia or tachycardia
- avoid hypotension- avoid decrease in SVR, very difficult to bring BP back up
- Optimize intravascular fluid volume to maintain venous return ad left ventricular filling
- **CPR is typically ineffective in pts with AS b/c it is impossible to get enough pressure to move blood through the small opening with compressions
22
Q
General anesthesia or Neuraxial anesthesia in pts with Aortic stenosis?
A
- General anesthesia preferred because of the sympathetic block that causes decrease in SVR
23
Q
What are some of the causes of mitral regurgitation?
A
- Usually due to rheumatic fever (book says this is uncommon) and is almost always associated with mitral valve stenosis
- Can be associated with ischemic heart disease or papillary muscle dysfunction
24
Q
What is the pathophysiology of mitral regurgitation?
A
- A portion of every stroke volume is regurgitated through the incompetent mitral valve back into the LA
- This causes LA volume overload and pulmonary congestion
- The amt that regurgitates depends on:
- size of mitral valve orifice
- heart rate, which determines the duration of ventricular ejection
- the pressure gradient across the mitral valve
- Pharmacological changes in SVR have a major impact on the regurgitation fraction
25
How is mitral regurgitation noted on a pulmonary arterial occlusion pressure waveform (PAOP)?
* Regurgitant flow causes an exaggerated V wave
* Size of V wave correlates with magnitude of regurgitant flow
* Pic below shows normal wave (about 12), will go to 20 or 25 with regurgitation
26
What are the goals for management of anesthesia in a pt with mitral regurgitation?
* Goals: **fast, full, forward**
* Avoid events that may further decrease cardiac output
* Avoid sudden decreases in HR
* avoid sudden increases in SVR
* monitor the size of the V wave as a reflection of regurgitant flow
* minimize drug-induced myocardial depression
* Ex. Etomidate or high dose opioid for induction
27
What influences the how you will manage the maintenance phas of anesthesia for a pt with mitral regurg?
Monitoring?
* Maintenance anesthesia is influenced by the degree of LV dysfunction
* If not severe:
* N2O and volatile agent (Iso, des, or sevo b/c of minimal negative inotropic effects)
* If severe:
* Use of high opioid technique minimizes drug induced myocardial depression- be aware that it might cause bradycardia
* Use of invasive monitoring depends on the complexity of procedure and magnitude of regurg
28
What are the causes of aortic regurgitation?
* Diseased leaflets:
* endocarditis\*, rheumatic fever, BAV
* Problems with aortic root:
* idiopathic aortic root dilation, aortic dissection\*, marfan syndrome, ankylosing spondylitis
* \*acute
29
What is the problem caused by aortic regurgitation?
* decrease in CO d/t regurgitation of part of the SV back into the LV during diastole
* Causes combined pressure and volume overload on LV
* Magnitude of regurgitation depends on:
* HR- amt of time available for the backward flow to occur
* SVR-pressure gradient across the aortic valve
30
What are goals for anesthesia in a pt with Aortic regurgitation.
* Avoid sudden decreases in HR
* Avoid sudden increases in SVR
* minimize drug induced myocardial depression
* Induction- use drugs likely to maintain forward left ventricular SV
* Maintenance:
* No LV dysfunction- N2O plus VA (Iso)
* LV compromise- consider opioid alone
31
How should you manage the fluid for a pt with mitral regurgitation?
monitoring?
* Prompt replacement of blood loss is important to maintain forward LV SV
* Bradycardia may require prompt treatment with atropine
* monitoring:
* based on complexity of surgery and severity of regurgitation
