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