CV Special Populations Flashcards
At rest, myocardium consumes ~ _____% of the oxygen delivered to it.
70%
Tachycardia effects both _______ and _________.
Supply and Demand
When the heart requires more oxygen, coronary blood flow and/or CaO2 must ________.
increase
What is the most useful measure of coronary perfusion?
MAP!!!!
____%of blood flow to the left ventricle happens during _______ when LVEDP is low -> diastolic time ______ as HR _______, thus giving less time for adequate perfusion
-80%
-diastole
-decreases
-increases
Decreased Oxygen Delivery:
-Decreased Coronary flow
-Decreased CaO2
-Decreased O2 extraction (left shift of HGB curve)
Increased O2 Demand
-Tachycardia
-HTN
-SNS stimulation
-Increased Wall Tension
-Increased LVEDV
-Increased Afterload and Contractilty
The heart acts as an “________” organ under stress
endocrine
ANP is released in response to _______ _________.
Volume Overload
B-type natriuretic peptide is released from the ventricles in response to ______ _______.
wall stress
______ is a marker for diagnosis of heart failure
BNP
Hallmark of LV Heart Failure:
Decreased EF with an increased EDV
-Ventricle doesn’t empty well
LV HF: shape change
-becomes more spherical shaped
LV HF: Volume overload causes _____ ______.
Eccentric Hypertrophy
Calculation for EF:
SV/EDV
EF levels (normal, mild, moderate, severe)
Normal: >55%
Mild: 45-54%
Moderate: 30-44%
Severe: <30%
Causes of Systolic HF:
CAD / myocardial Ischemia
Volume Overload ( d/t Valve insufficiency)
Dilated cardiomyopathy
Compensatory mechanism in Systolic HF:
SV reduces –> SNS activates –> raise the resting HR to try and maintain CO
Systolic HF: Anesthesia Considerations
Preload: already high, (avoid overload, diuretics if too high)
Afterload: DECREASE to reduce myocardial workload
-coronary pressure must be maintained
-SNP (nipride) works well if volume adequate
Contractility: may be reduced –> INOTROPES
HR: usually HIGH d/t SNS
-if EF low then HIGHER HR needed to perserve CO (do not decrease HR)
FULL FAST FOWARD
Left Heart Failure: Diastolic Dysfunction
-Ventricle doesn’t FILL properly
HALLMARK: symptomatic HF with preserved EF
Left HF Diastolic Dysfunction: Chronic pressure overload leads causes the myocardium to _______.
Pressure overload leads to ________ _______.
-thicken
- concentric hypertrophy
Left HF Diastolic Dysfunction: ______ ischemia from chronic _____ _____.
Demand
pressure overload
Most common type of heart failure in women and the elderly
Left HF Diastolic Dysfunction
Preserved EF = >40%
Left Heart Failure: Diastolic dysfunction
CAUSES:
Demand ischemia from chronic pressure overload
Myocardial ischemia
Stenotic heart valves
Hypertrophic cardiomyopathy
Chronic hypertension
Cor pulmonale
Obesity
Diastolic HF: Anesthetic Considerations
PRELOAD: volume required to stretch non-compliant ventricle
AFTERLOAD: usually already elevated, if not keep elevated to perfuse THICK myocardium
-PHENYLEPHRINE –> GIVE WITH INDUCTION
CONTRACTILITY: usually normal, caution with agents that depress function
HR: slow/normal to maximize diastolic time for coronary perfusion and decrease MVO2
** 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!
Diastolic HF: Anesthetic Considerations (2)
Similar to stenotic lesions: Slow, Full, Constricted
Right Ventricular Failure: The right heart is _______, more _______, and _______ than the left heart
thinner, more compliant and weaker
Most common cause of right heart failure is:
Left heart failure
Also caused by pulmonary HTN and right sided MI
_______ ______ HF causes systemic congestion, hepatomegaly, and peripheral edema
Right Sided
Anything that increases _____ can impair RV function
PVR
Factors that can increase PVR (RV HF)
Hypoxemia, hypercarbia, Acidosis
N2O and Desflurane can increase PVR
Treatment of Right Ventricular HF:
main goal is to improve contractility while reducing right heart afterload
Inotropes and decreased PVR
Management of right sided HF can be more difficult than left sided HF because fewer options exist for unloading and supporting the right ventricle
Remodeling can be reversed by _______ and ________.
Ace Inhibitors and aldosterone inhibitors
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
Malignant HTN —–> __________/__________
Hemorrhagic stroke/cerebral edema
Hypotension —–> ______________
cerebral hypoperfusion
Acute Pericarditis: Pathology
Usually from result of inflammation
Does NOT impair diastolic filling unless inflammation leads to constrictive pericarditis or tamponade
Most common cause of Acute Pericarditis (others as well)
VIRAL INFECTION
Dressler’s Syndrome (inflammation from necrotic myocardium s/p MI)
TB
Autoimmune diseases – RA, SLE, Scleroderma
Cardiac injury – trauma, surgery
Cancer (radiation)
Acute Pericarditis pain symptoms
Acute chest pain with pleural component
Increased pain with inspiration and postural changes
Pain relieved by leaning forward
Constrictive Pericarditis:
Fibrous tissue encapsulates the heart and limits its ability to expand during DIASTOLE
Constrictive Pericarditis: patient will have abnormal ________ ________.
diastolic filling
Ventricles adapt by increasing myocardial mass
Constrictive Pericarditis:
Increased _______
Decreased ________
Increased: filling pressures
Decreased: SV and CO
Constrictive Pericarditis: CAUSES
Cancer (radiation), cardiac surgery, rheumatoid arthritis, TB, uremia
Constrictive Pericarditis: Signs and Symptoms
Gradually increasing fatigue and dyspnea
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
T wave inversion or notched P waves on ECG
Pericardial shock
Kussmauls sign
JVD during inspiration
Constrictive Pericarditis: Treatment
Pericardiotomy (risky) high mortality
Hemorrhage and dysrhythmias common
Large bore Ivs
Invasive hemodynamic monitoring
Have a CPB machine ready and available in the room
Constrictive Pericarditis: Management (what to avoid, what to maintain)
Cardiac output is dependent on HR*
Avoid Bradycardia
Maintain Afterload
Meds to help preserve HR and Contractility (Constrictive Pericarditis)
Ketamine and Pancuronium are good
Opioids, benzos, etomidate are okay
Cardiac Tamponade: What is it?
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
Cardiac Tamponade (LV pressure, volume, CO, HR) Effects
Increased pericardial pressure compresses the heart
Increased LV pressure
Decreased ventricular volume = decreased SV, decreased CO, increased HR
Cardiac Tamponade: Causes
Trauma – blunt force trauma (major cause), sharp trauma, dissecting aortic aneurysm
Complications with cardiac surgery
Malignancy within the mediastinum
Expansion of pericardial effusions after pericarditis
Cardiac Tamponade: Becks Triad
Hypotension, JVD, Muffled heart tones
The most sensitive method to detect pericardial effusion and exclusion of tamponade
Echocardiogram
Definitive treatment of Cardiac Tamponade
pericardiocentesis
Cardiac Tamponade intubation considerations
Compression of heart, lungs, trachea, and esophagus d/t mass effect
Video laryngoscope, fiber optic, delicate intubation
Cardiac Tamponade- Anesthetic Management
If GA – primary goal is to preserve myocardial function
Stroke volume is severely decreased but increased SNS tone (increased contractility and afterload) provide compensation
Any drug that depresses the myocardium or reduces afterload can precipitate and CV collapse
____ preferred for pericardiocentesis
LA
Anesthesia Drugs to Avoid with Cardiac Tamponade
Halogenated agents
Propofol
Thiopental
High dose opioids
Neuraxial anesthesia
Drugs that are safer for Cardiac Tamponade
Ketamine
Nitrous oxide
Benzodiazepines
Opioids
Best anesthesia drug for cardiac tamponade?
Ketamine
Cardiac Tamponade- (HR, Rhythm, Preload, Afterload, Contractility)
Heart Rate = Maintain
Rhythm = NSR
Preload = Maintain or Increase
Contractility = Maintain or Increase
Afterload = Maintain
Most common cause of sudden cardiac death in young adults
Obstructive Hypertrophic Cardiomyopathy
LVOT obstruction caused by:
Congenital hypertrophy of intraventricular septum
Systolic anterior motion (SAM) of anterior leaflet of mitral valve
SAM is….
Systolic Anterior Motion of the Mitral valve
Conditions that distend the LVOT ——>
GOOD!
Conditions that narrow the LVOT ——>
BAD!
Surgical Procedures with Increased Risk for Infective Endocarditis
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
HALLMARK for Left Heart Failure: Diastolic Dysfunction
Symptomatic HF with preserved EF
Causes of Systolic HF:
CAD / myocardial Ischemia
Volume Overload ( d/t Valve insufficiency)
Dilated cardiomyopathy
