Cardiac special populations Flashcards
How much oxygen does the myocardium consume at rest?
70%
The heart ____ ____ meaningfully increase its extraction ratio when oxygen demand increase
The heart can not meaningfully increase its extraction ratio when oxygen demand increase
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
What causes increased oxygen demand?
Tachycardia
Hypertension
SNS Stimulation
Increased Wall Tension
Increased LVEDV
Increased Afterload
Increased Contractility
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
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
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%
What causes systolic heart failure?
all basically from an increase in volume
CAD / myocardial Ischemia
***Volume Overload ( d/t Valve insufficiency)
Dilated cardiomyopathy
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.
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
What happens to the myocardium with diastolic (concentric) heart failure?
Chronic pressure overload leads causes the myocardium to thicken
How do you treat diastolic heart failure?
Slow, Full, Constricted
-similar to stenotic lesions-
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!
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
What is the main goal of treatment for right heart failure?
to improve contractility while reducing right heart afterload
Inotropes and decreased PVR
What meds can reverse remodeling?
Ace Inhibitors/ aldosterone inhibitors
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
What are the complications of hypertension
Left ventricular hypertrophy
Ischemic heart disease
Congestive heart failure
Arterial aneurysm (aorta, cerebral)
Stroke
ESRD
Cerebral Autoregulation Curve
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?
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?
Cancer (radiation), cardiac surgery, rheumatoid arthritis, TB, uremia
Signs & Symptoms of constrictive pericarditis
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
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
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
