Week 3 Flashcards
Week 3: Anesthetic Management for Patients with Cardiovascular Disease
Coronary Artery Disease
- Cardiac anesthesia provider needs a..
- Good understanding of normal and altered cardiac physiology
- Working knowledge of the pharmacology of anesthetics, vasoactive, and cardio-active drugs
- To be familiar with the physiologic alterations associated with cardiovascular procedures
- Preventing myocardial Ischemia
- Avoid factors known to increase _______(1)
- Myocardial oxygen consumption (MVO2) is defined by the equation: MVO2 = _______(2) x ______(a)
- Avoid factors known to increase _______(1)
- Principle determinants of MVO2
- _______(3)
- _______(4)
Answers:
- MV02
- coronary blood flow
a. arteriovenous difference in O2 content. - Wall tension
- Contractility
Myocardial O2 Balance with CAD
- Typically _______(1) at rest
- Exercise/stress increases _______(2)
- Ischemic symptoms develop
- O2 requirements greater than existing coronary blood flow
- Coronary vascular _______(3) is exceeded
- Ischemic symptoms develop
- _______(4)
- Alterations in electrophysiology, metabolism, function
- Obstructions
- Large epicardial conductance vessels → The _______(5) have generally been viewed as conductance vessels that pose ______(a) to CBF.
- Normally, the resistance is _______(6)
- As the percent of stenosis increases, the resistance across the stenotic area increases
- Resistance begins to increase when lumen is reduced by > _______(7)
- Further restrictions, resistance increases dramatically
- _______(8), resistance across stenosis triples
- Small changes in vessel diameter can dramatically increase resistance and decrease CBF
Answers:
- asymptomatic
- MVO2
- reserve
- Angina
- epicardial coronary arteries
a. minimal resistance - almost zero
- 50%
- 80-90% stenosis
Remember Laplace’s Law
- Wall tension is directly proportional to _______(1) and radius
- Wall tension in inversely proportional to _______(2)
- Can decrease MVO2 by:
- Decreasing _______(3)
- Preventing or promptly treating ventricular _______(4)
Study the illustaration on GoogleDoc
LV Wall Stress = (LV Pressure) x (Radius) / 2(LV Wall Thickness)
HFrEF: Expected increased Radius and Decreased wall thickness
HFpEF: Increased Wall thickness BUT decreased Radius
Answers:
1. intracavitary pressure
2. wall thickness
3. intraventricular pressure
4. distention
Preload and Afterload
Preload
- Volume of blood in ventricles at end of diastole (end diastolic pressure)
- Increased in: _______(1), _______(2) of cardiac valves, _______(3)
Afterload
- Resistance left ventricle must overcome to circulate blood
- Increased in: _______(4), _______(5)
Athlete: Increased Thickness of Myocardium but body accommodates accordingly
Stucy the Myocardial Oxygen Supply Graphic Chart
Answers:
1. Hypervolemia
2. Regurgitation
3. Heart Failure
4. Hypertension
5. Vasoconstriction
Coronary Blood Flow
- Critical factors/modifiers
- Perfusion pressure
- Vascular tone of the coronary circulation
- Heart rate (time available for perfusion)
- Severity of intraluminal obstructions
- Presence of collateral circulation
- What area of the heart is most vulnerable to ischemia?
- _______(1) of the LV
Myocardial O2 balance with CAD: Compensatory Mechanisms
- Collateral circulation
- Develops and matures over time
- Physiologic bypass of the obstructed vessels
- Heart can generate new blood flow if an important vessel becomes obstructed
- Resting CBF maintained by progressive _______(2) at the microcirculation
- As proximal stenosis increases, autoregulation seeks to preserve flow
- Basal flow can increase _______(3) times with maximal vasodilation
- Coronary vascular reserve progressively decreases and flow becomes _______(4)
Answers:
- Subendocardium
- vasodilation
- 4-5
- pressure dependent
Hemodynamic Goals for Coronary Artery Disease
Parameter | Goal
— | —
Preload | Keep the heart small: decrease wall tension (diameter) and LVEDP; increase perfusion pressure gradient
Afterload | Maintain: Hypertension is better than hypotension
Contractility | Depress (if LV function is normal)
Rate | Slow
Rhythm | Sinus
MVO2 | Monitor for and treat “supply” —related issues
CPB | Elevated filling pressures are usually not needed after CABG
Small, Steady, Slow, and Sinus
CPB=Cardiopulmonary Bypass
Preoperative Evaluation
- Goals:
- Define risk
- Determine need for further testing
- Form a safe anesthetic plan
- Need for additional medications (_______(1) or anti-hypertensives)
- Interventional therapies
- Surgery
- Recognize the S & S of uncontrolled HTN, myocardial ischemia, CHF, valvular heart disease, and cardiac dysrhythmias
What are the risks of a perioperative event? ______(2)
Answers:
1. beta blockers
2. Arrhythmias, MI, heart failure, death
Goldman Cardiac Risk Index
- Studied over 4,000 patients aged 50 years or older who were having elective, major noncardiac procedures
- Found 6 _______(1) of complications
- Complications increased with number of risk factors present
Table 1. Revised Cardiac Risk Index
Lee Variables
1. _______(2)
2. Ischemic heart disease (includes any of the following: history of myocardial infarction; history of positive exercise test; current complaint of chest pain that is considered to be secondary to myocardial ischemia; use of nitrate therapy; electrocardiography with pathologic Q waves)
3. _______(3)
4. History of cerebrovascular disease
5. Preoperative treatment with _______(4)
6. Preoperative serum creatinine > 2.0 mg/dL
No. of Variables | Risk of Major Postoperative Cardiac Complication
— | —
0 | 0.4%
1 | 0.9%
2 | 7.0%
≥3 | 11.0% High risk
Adapted from reference 19.
Goldman created RICHES
Risky Surgery
Ischemic Heart Dse
Congestive Heart Failure
History of CVD
Endocrine (insulin use)
Serum Creatinine > 2.0
RCRI = REVISED CARDIAC RISK INDEX
Pathological Q waves usually indicate current or prior myocardial infarction. SEE BELOW
Answers:
1. independent predictors
2. High-risk type of surgery
3. Congestive heart failure
4. insulin
Patients with Symptomatic CAD
- Preoperative Evaluation may show changes in frequency or pattern of angina symptoms
- Some patients may have more atypical or undiagnosed (_______(1)) features
- _______(2)
- _______(3)
- _______(4)
- Unstable angina is associated with high perioperative risk of MI
- Perioperative period associated with _______(5) an ______(6) in endogenous catecholamines (increasing risk of MI)
- Upregulate/Downregulate? Maintain ______(7) of patients normal MAP
Answers:
1. silent
2. Elderly
3. Women
4. Diabetics
5. hypercoagulable state
6. increase
7. 20%
Preoperative Evaluation: HISTORY
- HTN: severity and duration, medications
- Smoking
- High cholesterol
- Symptoms of any conditions
- Myocardial ischemia
- Ventricular failure
- PVD
- Diabetes (_______(1) of CAD, _______(2) and _______(3))
- Chest pain, exercise tolerance, SOB
- Edema
- Valvular Disease
- Angina, dyspnea, syncope, CHF
Answers:
1. higher incidence
2. silent MI
3. ischemia
PHYSICAL EXAM
- HEART SOUNDS
- MURMURS
- PMI LATERAL TO NORMAL (CARDIOMEGALY)
- _______(1) (LVH)
- S4 gallop associated with left ventricular hypertrophy (LVH), is a specific heart sound heard during a cardiac examination, indicating a _______(2) or hypertrophic left ventricle. This sound is caused by the atria contracting forcefully to overcome the _______(3) of the stiff ventricle during ______(a).
- It’s often an indication of underlying heart conditions, such as ______(b), that have led to _______(4) and _______(5).
- S4 gallop associated with left ventricular hypertrophy (LVH), is a specific heart sound heard during a cardiac examination, indicating a _______(2) or hypertrophic left ventricle. This sound is caused by the atria contracting forcefully to overcome the _______(3) of the stiff ventricle during ______(a).
- CAROTID BRUITS (VASCULAR DISEASE AFFECTING CORONARY CIRCULATION)
Answers:
1. S4 GALLOP
2. stiff
3. resistance
a. late diastole
b. hypertension or aortic stenosis
4. thickened heart muscle walls
5. reduced ventricular compliance
LUNG SOUNDS
- Pulmonary RALES and _______(1) (CHF)
- S3 gallop is a heart sound that typically occurs just after the S2 (second heart sound). It’s often described as a “lub-dub-ta” sound and is associated with heart failure or conditions leading to increased filling pressures. The sound is produced when a large amount of blood enters a _______(2) or failing ventricle, causing vibrations in the ventricular walls — large bc volume overload “CHF!!”
- While it can be normal in______(a), in older individuals, it often indicates a pathological state like _______(3).
- Memory Device: Think S4 for as a Strong Fort! S3 as a Dilated Sea!
- S3 gallop is a heart sound that typically occurs just after the S2 (second heart sound). It’s often described as a “lub-dub-ta” sound and is associated with heart failure or conditions leading to increased filling pressures. The sound is produced when a large amount of blood enters a _______(2) or failing ventricle, causing vibrations in the ventricular walls — large bc volume overload “CHF!!”
BLOOD PRESSURE MEASUREMENT (SUPINE AND STANDING)
- ORTHOSTATIC CHANGES (VOLUME DEPLETION, HEMORRHAGE, EXCESSIVE VASODILATION)
- One study showed: Admission ______(b) was the best predictor of response to laryngoscopy (_______(4)?)
Answers:
1. S3 GALLOP
2. dilated
a. children or young adults
3. congestive heart failure
b. BP and HR
4. anxiety
Electrocardiogram
- Provides info on state of the myocardium and coronary circulation
- Rate, Bundle branch blocks, lv
- Old injuries/infarcts
- Pacer spikes
- Conduction abnormalities
ECG Changes during Myocardial Infarction (MI)
Location of MI | Leads Affected | Vessel Involved | ECG Changes
— | — | — | —
Anterior wall | V2 to V4 | Left anterior descending artery (LAD) - Diagonal branch | Poor R-wave progression ST-segment elevation T-wave inversion
Septal wall | V1 and V2 | Left anterior descending artery (LAD) - Septal branch | R wave disappears ST-segment rises T-wave inverts
Lateral wall | I, aVL, V5, V6 | Left coronary artery (LCA) - Circumflex branch | ST-segment elevation
Inferior wall | II, III, aVF | Right coronary artery (RCA) - Posterior descending branch | T-wave inversion ST-segment elevation
Posterior wall | V1 to V4 | Left coronary artery (LCA) - Circumflex branch Right coronary artery (RCA) - Posterior descending branch | Tall R waves ST-segment depression Upright T waves
Posterior wall only one with _______(1)
Lateral wall is the only one without _______(2), whilst Posterior wall has _______(3) T Waves
The LAD causes loss of _______(4), whilst poster wall inc _______(5)
Posterior wall as a _______(6) MI of Anterior wall MI — _______(7) of LAD infarct
Answers:
1. ST-depression
2. T-wave inversion
3. Upright
4. R-wave progression
5. R waves
6. reciprocal
7. mirror image
Abnormal “Q” waves
- Highly suggestive of _______(1)
- 30% of myocardial infarctions occur without symptoms (silent MI) with highest incidence in _______(2) and _______(3)
- Presence of _______(4) on preoperative EKG in a high risk patient = high indication of increased perioperative risk and possible active ischemia
- THINK Young, African American Athlete- Do Not Ignore this abnormality
Preoperative Evaluation might include:
- CXR
- ECHO results (LVH, DIASTOLIC AND SYSTOLIC FUNCTION ESPECIALLY IN HEART FAILURE)
- Cardiac tests
- LABORATORY FINDINGS
- RENAL: SERUM CREATININE AND _______(5)
- POTASSIUM (DIURETICS, DIGOXIN OR RENAL IMPAIRMENT, EKG CHANGES/ECTOPY)
- Magnesium
- Hemoglobin/Hematocrit
Answers:
1. past MI
2. diabetics
3. hypertensives
4. Q wave
5. BUN LEVELS
Surgical Procedure Risk
- Major vascular procedures associated with _______(1)
- ACC/AHA risk stratification
- Other high risk procedures
- Abdominal
- Thoracic
- Orthopedics
TABLE 21–3 Cardiac risk1 stratification for noncardiac surgical procedures.
Risk Stratification | Procedure Examples
— | —
Vascular (reported cardiac risk often more than 5%) | Aortic and other major vascular surgery Peripheral vascular surgery
Intermediate (reported cardiac risk generally 1% to 5%) | Intraabdominal and intrathoracic surgery Carotid endarterectomy Head and neck surgery Orthopedic surgery Prostate surgery
Low2 (reported cardiac risk generally less than 1%) | Endoscopic procedures Superficial procedure Cataract surgery Breast surgery Ambulatory surgery
Which of the following is the higher stratification surgery? A carotid endarterectomy, intrathoracic surgery, or peripheral vascular surgery?
Ans: _______(2)
PLEASE STUDY
2014 ACC/AHA guidelines
Answers:
1. highest incidence of complications
2. PVS
Importance of Exercise Tolerance
- _______(1) is one of the most important determinants of perioperative risk and the need for further testing and invasive monitoring
- Good exercise tolerance suggests that the myocardium can be stressed without failing (climbing two flights of stairs or walking 4 blocks) — _______(2)
- Assessed with a questionnaire that assesses daily activity
- (hip/knee issues?) — _______(3) mean you are cardiac crippled, just restricted movement
- Treadmill testing
Answers:
1. Exercise tolerance
2. 4 METS Equivalent
3. does not necessarily
TABLE 21-2
TABLE 21–2 Estimated energy requirements for various activities.
Can you …
1 MET
- Take care of yourself?
- Eat, dress, or use the toilet?
- Walk indoors around the house?
- Walk a block or 2 on level ground at 2 to 3 mph (3.2 to 4.8 kph)?
4 METs
- Do light work around the house like dusting or washing dishes?
Can you …
4 METs
- Climb a flight of stairs or walk up a hill?
- Walk on level ground at 4 mph (6.4 kph)?
- Run a short distance?
- Do heavy work around the house like scrubbing floors or lifting or moving heavy furniture?
- Participate in moderate recreational activities like golf, bowling, dancing, doubles tennis, or throwing a baseball or football?
Greater than 10 METs
- Participate in strenuous sports like swimming, singles tennis, football, basketball, or skiing?
TABLE 21-13
TABLE 21–13 Modified New York Association functional classification of heart disease.
Class | Description
— | —
I | Asymptomatic except during severe exertion
II | Symptomatic with moderate activity
III | Symptomatic with minimal activity
IV | Symptomatic at rest
Choice of Anesthetic - Regional
- Regional anesthesia
- Dense analgesia
- Blockade of afferent and efferent nerve conduction (_________(1))
- Major disadvantages
- Hypotension from sympathetic block
- ______(a) in wall tension with volume loading could precipitate subendocardial ischemia w/ CAD
- _________(2) may be better
- _________(3) is your best choice
- _________(4) may be problematic after return of vascular tone
- _________(2) may be better
Answers:
1. catecholamine release is suppressed
a. Increase
2. Alpha-agonist
3. Phenylephrine
4. Large volume loads
Choice of Anesthetic: General
- General anesthesia with Opioids
- Lack of myocardial depression (desirable in patients with markedly impaired ventricular function)
- Suppression of stress response
- Reduction of HR
- Hemodynamic stability
- Can supplement with volatile anesthetics
- Muscle relaxants
- Emergence: relatively comfortable and hypothermia avoidance
Selection of Anesthetic
- There is no ideal anesthetic for _______(1)
- Opioids
- Advantages: lack of myocardial depression, stable hemodynamic state and reduction of heart rate
- High dose valuable only in the patient with _______(2)
- Advantages: lack of myocardial depression, stable hemodynamic state and reduction of heart rate
- Inhalational
- Dose-dependent hemodynamic changes, reversible, titratable myocardial depression, suppression of sympathetic responses to surgical stress
- _______(3) the myocardium from ischemia and reperfusion injury and reduces infarct size
- Dose-dependent hemodynamic changes, reversible, titratable myocardial depression, suppression of sympathetic responses to surgical stress
- Adjuncts: propofol, midazolam, dexmedetomidine
Answers:
1. patients with CAD
2. severe myocardial dysfunction
3. Protect
Treatment of Intraoperative Problems
- Sinus tachycardia
- Increase anesthesia
- Beta blockers
- Increase PCWP
- NTG (add inotrope or alpha agonist if decrease in BP)
- _______(1)
- _______(2) with good LV function
- HTN
- Anesthesia,
- vasodilators,
- beta blocker if tachycardia
Answers:
1. Restrict fluids
2. Volatile anesthetic
Treatment of Intraoperative Problems
- Hypotension
- Volume, if hypovolemic
- ______(a) agonist, if transient and not hypovolemic
- _______(1)
- Inotrope
- Associated with increased PCWP and decrease CO
- Increase MVO2 offset by increased CPP and decreased ventricular size
- Associated with increased PCWP and decrease CO
- Neo/NTG
- Maintains perfusion pressure and keeps heart small
- _______(2)
- Maintains perfusion pressure and keeps heart small
Answers:
a. Alpha
1. phenylephrine
2. Good for ischemic changes
Valvular Heart Disease
Valve Review Sheet
- Please print and review the Valve Review Worksheet, which I posted for you under Module 1.
- This is a very _______(1) guide to keep with you during your Clinical rotation.
Pathophysiology of Valvular Heart Disease
- Causes chronic volume and _______(2) overload
- Ventricular Hypertrophy: increased left ventricular mass
- Pressure overload: Concentric (_________(3), normal chamber size)
- Volume Overload: Eccentric (_________(4) and dilated cardiac chamber)
2 types of hemodynamic overload → HF
Answers:
1. handy
2. pressure
3. increase in ventricular wall thickness
4. normal wall thickness
History and Physical
- Should have a high index of suspicion if patient has a history of rheumatic fever, IV drug abuse, genetic disorders (i.e., _______(1)), heart surgery as a child, or heart murmurs
- Exercise tolerance usually decreased
- Exhibit signs/symptoms of heart failure to include:
- dyspnea, orthopnea, fatigue, pulmonary rales, jugular venous congestion, _______(2) congestion, or edema
- Angina can occur in patients with hypertrophied _______(3)
- A-Fib often accompanies _______(4) of the atria
Tests to evaluate valvular heart disease:
- Echocardiography with doppler
- Measures size and function of the chambers
- Pressure gradients of the valves
- Valve area measurements
- Severity of disease determined
- EKG: Evidence of ischemia, arrhythmias, atrial enlargement, ventricular hypertrophy
- CXR: enlargement of chambers, pulmonary HTN, pulmonary edema and effusions
- Cardiac Cath: used before surgery to diagnosis ______(5), measurement of heart pressures in the chambers and pressure gradients across valves
Answers:
1. Marfans
2. hepatic
3. left ventricle
4. enlargement
5. CAD
Transesophageal Echocardiography (TEE)
- Can be used in the OR during valve surgery
- Evaluate severity of valvular disease, structural and functional changes
- Evaluation of the valve repair or function of artificial valves
- Systolic and diastolic function of the Left and right ventricles before and after _______(1)
- Determines postsurgical management
Pressure-Volume Loops
- Please watch and review the videos by the Khan Academy posted under Module 6:
- Pressure in the left heart – Part I
- Pressure in the left heart – Part II
- Pressure in the left heart – Part III
- These videos were absolute _______(2)
(Know these, compare these, know what they’re describing, how do they change due to pathology)
Answers:
1. bypass
2. basura
Pressure-Volume Loops
- Plots LV pressure against volume through one complete cardiac cycle
- Each valvular lesion has a unique profile that suggests compensatory physiologic changes by the left ventricle
Match the event/description with the valve action (answer below the next img)
A. Aortic Valve Closes
B. Aortic Valve Opens
C. Mitral Valve Opens
D. Mitral Valve Closes
- End Systolic Volume
- Beginning of Systole
- End Diastolic Volume
- Represents Preload
- Beginning of Ventricular Filling
Preload is represented by the point just before the mitral valve closes, indicating the ventricle is at its maximum volume in diastole.
Please study the Pressure Volume Loop graph
P-V Loops: Valve disease
- Definitely qs on this
- A = normal - LV
- B = mitral stenosis
- C = aortic stenosis
- D = mitral regurgitation (chronic)
- E = aortic regurgitation (chronic)
Aortic Stenosis (AS) “______(a)”
Pathology of Aortic Stenosis
- Most common valvular disease in the U.S.
- Normally, composed of 3 semilunar cusps
- Classified as valvular, subvalvular, or supravalvular obstruction
- Concentric hypertrophy develops: thickened ventricular wall with normal chamber size
Answers:
A -> 1. End Systolic Volume
B -> 2. Beginning of Systole
C -> 3. End Diastolic Volume
D -> 5. Beginning of Ventricular Filling
a. FULL, SLOW, AND CONSTRICTED
Pathophysiology of Aortic Stenosis
- Decreasing LV compliance accompanies ______(a) LV end-diastolic pressure
- Contractility and ejection fraction can be maintained until ______(b) disease process
- Atrial contraction account for 40% of the ventricular filling (normally 20%)
- Clinical factors associated with AS:
- ______(c)
- Causes:
- ______(d) (more common in developing countries)
- Calcification of tri-leaflet
- Congenital _______(1) valve
Presentation of Aortic Stenosis
- Angina
- Angina can occur in the absence of CAD
- Thickened myocardium is susceptible to ischemia and elevated LV end-diastolic pressures that decrease coronary perfusion pressure
- ADP/LVEDP=CPP
- Syncope
- CHF
- Tighter AS, LV systolic pressure increases to a level where LV hypertrophy cannot normalize the wall tension so the heart starts to dilate with symptoms of systolic dysfunction and decreasing cardiac output concomitant with symptoms of.
- AS is S.A.D. → syncope, angina, _______(2) (from CHF/pulmonary involvement)
- Life expectancy with symptoms of:
- Angina: ______(e) years
- Appearance of syncope: ______(f) years
- Appearance of CHF: ______(g) years
Answers:
a. elevated
b. late
c. Older, male, smoker, HTN, Hyperlipidemia
d. Rheumatic fever
1. bicuspid
2. dyspnea
e. 5
f. 3-4
g. 1-2