Cardiac special populations Flashcards by Frank E

How much oxygen does the myocardium consume at rest?

70%

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The heart ____ ____ meaningfully increase its extraction ratio when oxygen demand increase

The heart can not meaningfully increase its extraction ratio when oxygen demand increase

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What causes decreased oxygen delivery

Decreased Coronary Flow
Tachycardia
Decreased aortic pressure
Decreased vessel diameter
(spasm or hypocapnia)
Increased LVEDP
Decreased CaO2
Hypoxemia
Anemia
Decreased Oxygen Extraction
Left shift of HGB dissociation
curve (decreased P50)
Decreased capillary
distention

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What causes increased oxygen demand?

Tachycardia
Hypertension
SNS Stimulation
Increased Wall Tension
Increased LVEDV
Increased Afterload
Increased Contractility

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What is the hallmark of systolic heart failure (eccentric hypertrophy)?

decreased EF with and increased EDV

Since the heart can’tsqueeze well, a greater amount of blood remains in the ventricle after each contraction

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What happens to chamber size with systolic HF?

Chamber size increases in an attempt to preserve stroke volume

Becomes more spherical shaped

Volume overload causes eccentric hypertrophy

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Degree of systolic heart failure by EF classification

Calculation: SV/EDV

Normal: >55%
Mild: 45-54%
Moderate: 30-44%
Severe: <30%

APEX
Normal: >50%
Mild: 41-49%
Moderate: 36-40%
Severe: <24%

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What causes systolic heart failure?

all basically from an increase in volume
CAD / myocardial Ischemia
***Volume Overload ( d/t Valve insufficiency)
Dilated cardiomyopathy

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How do you treat systolic HF?

Fast, Full, Forward (reduce afterload)

-similar to regurg-

If EF is low, higher HR is needed to preserve C.O.

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What is the hallmark of diastolic HF?

symptomatic HF with preserved EF

Diastolic failure occurs when the heart is unable to relax and accept incoming volume

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What happens to the myocardium with diastolic (concentric) heart failure?

Chronic pressure overload leads causes the myocardium to thicken

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How do you treat diastolic heart failure?

Slow, Full, Constricted

-similar to stenotic lesions-

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What is crucial in treating diastolic heart failure?

The LV with concentric hypertrophy is prone to ischemia, Maintenace of a high MAP and slow normal HR is crucial. Hypotension should be treated promptly with phenylephrine!

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What is the most common cause of right heart failure?

Most common cause of right heart failure is left heart failure

Also caused by pulmonary HTN and right sided MI

Anything that increases pulmonary vascular resistance can impair RV function
Hypoxemia, hypercarbia, Acidosis

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What is the main goal of treatment for right heart failure?

to improve contractility while reducing right heart afterload

Inotropes and decreased PVR

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What meds can reverse remodeling?

Ace Inhibitors/ aldosterone inhibitors

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Stages of hypertension

Normal 120/80
Pre-hypertension 120-129/80
Stage 1 hypertension 130-139/80-90
Stage 2 hypertension 140/90
Hypertensive crisis 180/120

Primary – no identifiable cause (95% of cases)

Secondary – identifiable cause (5% of cases)
Coarctation of the aorta, Renovascular disease, Cushing syndrome, Conn’s syndrome, Pheochromocytoma, Pregnancy-induced HTN

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What are the complications of hypertension

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Left ventricular hypertrophy
Ischemic heart disease
Congestive heart failure
Arterial aneurysm (aorta, cerebral)
Stroke
ESRD

Cerebral Autoregulation Curve

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Describes the range of blood pressures where cerebral perfusion remains constant

*Chronic hypertension shifts the curve to the RIGHT

This helps the brain tolerate a higher range of blood pressures

However, it can not tolerate lower blood pressures

Blood pressures past the range of autoregulation is pressure dependent
Malignant HTN  hemorrhagic stroke/cerebral edema
Hypotension  cerebral hypoperfusion

What is constrictive pericarditis?

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Fibrosis or any condition where the pericardium becomes thicker

During diastole, ventricles cannot relax fully  reduces compliance and limits filling  ventricular pressure increases and creates a back pressure on peripheral circulation

Ventricles adapt by increasing myocardial mass

What is the cause of constrictive pericarditis?

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Cancer (radiation), cardiac surgery, rheumatoid arthritis, TB, uremia

Signs & Symptoms of constrictive pericarditis

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Kussmauls sign – JVD during inspiration

Pulsus Paradoxes - decreased SBP by 10 mmHg during inspiration

Increased venous pressure – distended neck veins, hepatomegaly, ascites, peripheral edema

Atrial dysrhythmias

Pericardial shock

Little bit about the pericardium

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Pericardium surrounds the heart and provides a minimal friction environment
Composed of 2 layers that are separated by 10-15 ml of clear fluid
Visceral layer is attached to myocardium
Parietal layer is attached to the mediastinum

Treatment for pericarditis

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Pericardiotomy (Hemorrhage and dysrhythmias common)

Cardiac output is dependent on HR*
Avoid bradycardia

Preserve HR and contractility

*Ketamine and Pancuronium are good

Opioids, benzos, etomidate are okay

Caution with volatile anesthetics

Maintain afterload

What is acute Pericarditis?

Usually from result of inflammation Does NOT impair diastolic filling unless inflammation leads to constrictive pericarditis or tamponade Caused by: Infection (viral most common) Dressler's Syndrome (inflammation from necrotic myocardium s/p MI) SLE Scleroderma Trauma Cancer (radiation)

Signs and symptoms of acute pericarditis

Acute chest pain with pleural component - Increased pain with inspiration and postural changes Pain relieved by leaning forward Pericardial friction rub ST elevation with normal enzymes Fever

Treatment for acute pericarditis

Usually resolves spontaneously Drugs to manage symptoms: Salicylates Oral analgesics corticosteroids

Describe tamponade

Accumulation of fluid inside the pericardium  pericardial pressure high enough to compress myocardium  interferes with the hearts ability to fill and act like a pump As ventricular compliance deteriorates, left & right diastolic pressures (CVP & PAOP) begin to equalize Increased pericardial pressure compresses the heart Increased LV pressure Decreased ventricular volume = decreased SV, decreased CO, increased HR

What happens to CO, SV, and HR with tamponade?

decreased SV, decreased CO, increased HR

Signs and symptoms of tamponade

Becks Triad: Hypotension, JVD, Muffled heart tones Pulses Paradoxes: Decreased SBP by 10 mmHg during inspiration Kussmaul’s Sign Increased CVP and JVD during inspiration Reduced EKG voltage Compression of heart, lungs, trachea, and esophagus d/t mass effect

What drugs can you give for anesthesia plan for tamponade

Drugs that are safer: Ketamine Nitrous oxide Benzodiazepines Opioids Drugs to AVOID: Halogenated agents Propofol Thiopental High dose opioids Neuraxial anesthesia

What is Obstructive Hypertrophic Cardiomyopathy also called?

Hypertrophic obstructive cardiomyopathy Asymmetrical septal hypertrophy Idiopathic hypertrophic subaortic stenosis

What is Obstructive Hypertrophic Cardiomyopathy?

Most common cause of sudden cardiac death in young adults LVOT obstruction caused by: Congenital hypertrophy of intraventricular septum Systolic anterior motion (SAM) of anterior leaflet of mitral valve

When is SAM likely to occur and how is it diagnosed?

Occur after mitral valve repair and diagnosed by TEE

When does SAM occur?

When the ventricle contracts forcefully or quickly - greater tendency of the anterior leaflet of the mitral valve to reduce flow through or completely obstruct the LVOT Occurs during systole Problem is proximal to aortic valve, not the valve itself

Most common cause of sudden cardiac death in young adults

Obstructive Hypertrophic Cardiomyopathy / SAM

Do we want to distend or narrow the LVOT?

DISTEND!

What distends the LVOT?

↑ Systolic volume (↑ preload or ↓ HR) ↓ Contractility ↑ Ao Pressure

What narrows the LVOT?

↓ Systolic volume (↓ preload or ↑ HR) ↑ Contractility ↓ Ao Pressure

What is infective endocarditis?

Bacteria enters the bloodstream and find their way to a heart valve, chamber, or blood vessel

These are at risk for infective endocarditis and should receive pre-op abx

Previous infective endocarditis Prosthetic heart valve Unrepaired cyanotic congenital heart disease Repair congenital heart defect if repair < 6 months old Repaired congenital heart disease with residual defects that have impaired endothelialization at the graft site

infective endocarditis abx not required for

CABG, Coronary stent placement, Unrepaired cardiac valve disease including mitral valve prolapse

Infective endocarditis increased risks

Dental procedures involving gingival manipulation and/or damage to mucosal lining Respiratory procedures that perforate the mucosal lining Biopsy of infected lesion on skin or muscle

Infective endocarditis ABX prophylaxis ___ required for: GI endoscopic procedures w/o infection and GU procedures without infection

ABX prophylaxis not required for: GI endoscopic procedures w/o infection and GU procedures without infection

Cardiac special populations Flashcards

(44 cards)