Valvular Disease Flashcards
Drug therapy for valvular disease
1) Digitalis (Digoxin)
- Given to increase contractility and low the ventricular response in those with a-fib
2) Diuretics
- May be given for excess intravascular fluid volume, but resultant hypokalemia can place at risk for digitalis toxicity
3) Prophylactic Antibx
- Recommended for the protection against the development of infective endocarditis
Tests for valvular heart disease
1) Doppler Echo
2) Cardiac cath to measure the severity of valvular heart disease
3) ABG may show low O2 and signs of VQ mismatch
Patho of mitral stenosis
Usually due to fusion of the mitral valve leaflets at the commissures during the healing process of acute rheumatic fever
Normal valve area is 4-6cm2
When valve area is
Adverse effects that may happen d/t mitral stenosis
Left atrial enlargement - Predisposes to a-fib A-fib can cause thromboemboli formation - Pt will be on anticoagulants Blood gets backed up. Pt will experience dyspnea on exertion when CO is increased.
Severe MS can lead to
CHF
Overall goal for mitral stenosis disease in anesthesia
Slow, tight, full
Slow: Avoid tachycardia or a-fib with RVR
Tight: Tight control of blood volume. Avoid marked increases in blood volume from over-transfusion or head-down positions. Tight fluid administration, give blood or colloids.
Full: Maintain preload. We need adequate pressures to overcome the stenosed valve. Large decreases in SVR will drop preload. IAs will drop SVR a lot.
Also don’t do anything that will increase PVR and cause RV failure.
Induction with valvular disease
Etomidate is probably best. We want to avoid things that increase HR (ketamine) or abruptly decrease SVR (propofol).
Slow, tight, full mothafucka
Patho of mitral regurgitation
Usually d/t rheumatic fever and is almost always associated with mitral stenosis.
Causes fluid overload in the LA by retrograde flow during ventricular contraction
Appearance of mitral regurgitation on PAOP tracing
Reguritant flow causes V wave on PAOP
Size of the V wave correlates with the magnitude of regurgitant flow
Anesthetic goals in mitral regurgitation
Fast, full, forward
Fast: Avoid sudden decreases in HR, which allows more time for blood to flow backwards
Full: Avoid sudden increases in SVR, which would promote backward flow
Forward: minimize myocardial depression
Patho of aortic stenosis
If purely AS, it’s usually d/t calcification of a congenitally abnormal valve.
If in association with MVS, then it was due to rheumatic fever.
Normal valve area is 2.5-3.5cm2.
Significant AS is associated with valve area 50mmHg.
Classic symptom triad with AS
Angina
DOE
Syncope
General anesthetic goals for the pt with AS
Maintain NSR:
- Need time for atrial kick
Avoid bradycardia:
- BP is very dependent on HR. These pts have a very low SV, so a higher HR is needed to maintain a normal CO and BP.
Avoid sudden increases or decreases in SVR
Ensure adequate fluid volume for venous return and ventricular filling (frank starling mechanism!)
Is RA or GA preferred in AS?
GA is preferred.
RA causes sympathectomy and drop in SVR
Patho of aortic regurgitation
Acute:
- Infective endocarditis
- Trauma
- Dissection of thoracic aneurysm
Chronic:
- Rheumatic fever
- Chronic HTN