Perioperative Heart

Front 1

Normal Coronary Blood Flow Parameters:

Back 1

225-250mL/min, 4-7% of CO

Front 2

Coronary Autoregulation Parameters:

Back 2

50-120mmHg (MAP)

Front 3

Coronary Perfusion Pressure (CPP):

Back 3

CPP=DBP-LVEDP
Normal range 50-80mmHg
Main determinent of CPP is DBP

Front 4

Coronary Flow Reserve:

Back 4

Resting Coronary Blood Flow
(-) Maximal Coronary Blood Flow; the smaller the difference = smaller the reserve

Front 5

Factors that Increase Myocardial Supply:

Back 5

-Coronary blood flow (autoregulation)
-Increased DBP
-Decreased HR
-Increased Oxygenated Hgb

Front 6

Myocardial ischemic threshold:

Back 6

The point in which development of ischemia occurs, most significant cause is increased HR

Front 7

Preload Desired with Cardiovascular Disease:

Back 7

Decreased, yet adequate to maintain CPP & adequate Stroke Volume

Front 8

Afterload Desired with Cardiovascular Disease:

Back 8

Maintain or slightly decrease to "unload" heart, not a dramatic decrease that would trigger barorecpetor = increased HR (bad)

Front 9

Contractility Desired with Cardiovascular Disease:

Back 9

If LV good then slight depression; if LV bad then depression could cause CHF

Front 10

Factors that increase myocardial rate of O2 consumption to the greatest:

Back 10

(Most to least):
-Increased HR
-Increased contractility
-Increased wall tension

Front 11

Energy Starvation Hypothesis

Back 11

With decreased amounts of substrate and decreased amounts of O2 there is decreased energy production & decreased pumping efficiency = potential for ischemia

Front 12

Normal B/P:

Back 12

<120 systolic <80 diastolic

Front 13

Prehypertension:

Back 13

120-139 systolic
80-89 diastolic

Front 14

Hypertension Stage 1:

Back 14

140-159 systolic
90-99 diastolic

Front 15

Hypertension Stage 2:

Back 15

>160 systolic
>100 diastolic

Front 16

Idiopathic HTN:

Back 16

Essential or idiopathic HTN accounts for 90% of HTN, unknown etiology, thought d/t ANS dysfunction = chronic vasoconstriction, hyperactive renin-aldosterone system, or increased amounts of Ca+ stores

Front 17

Changes in CO & SVR with HTN:

Back 17

Initially have increased cardiac output with normal SVR, over time CO returns to normal but SVR increases

Front 18

Left Ventricular Hypertrophy:

Back 18

Concentric/wall thickens, increased muscle from pushing against increased SVR

Front 19

Composition of Plaque:

Back 19

-Cholesterol
-Ca+
-Fibrin
-Inflammatory cells

Front 20

Stable Angina:

Back 20

-Occurs when coronary artery occlusion ~50-70%
-With increased demand cannot meet supply needs develop s/s of ischemia
-Relieved with rest, O2, NTG
-Usually <15min
-No increased morbidity/mortality associated with stable angina in cardiac patients presenting for noncardiac surgery

Front 21

Unstable angina:

Back 21

abrupt or new onset increase in severity, frquency, duration of anginal attacks (>3/day), angina at rest, no precipitating factors, usually lasts >30min, associated with MI and plaque disruption & micro-emboli

Front 22

Myocardial Ischemia/Infarction Time Periods:

Back 22

-<40 minutes reperfusion minimal damage
-40min-4hrs = necrosis
->6hrs = infarcted tissue

Front 23

Myocardial stunning & Ischemic preconditiong:

Back 23

even within infarcted tissue there are viable myocytes, stunning occurs as a r/o brief period of ischemia followed by reperfusion, resolves in 42-78hrs.
-Myocytes become ineffective which decreases metabolic rate, decreases MVO2, & protects cells in low O2 environment

Front 24

Reperfusion of ischemic tissue:

Back 24

Ischemic tissue exposed to O2 then O2 free radicals (substrate, acid, free Ca+, mediators of inflammation) are created and released that destroy cell membranes, myocardium, mitochondria

Front 25

Coronary Artery Spasm:

Back 25

"Prinzmetal's angina," unknown etiology, thought d/t stress, hyperventilation, exertion, females>males, no CAD, trt: Nitrates, Ca+ channel blockers, spasm can lead to infarction!

Front 26

Top 3 objective factors that increase the intraoperative risk of myocardial ischemia/infarct:

Back 26

History MI, CHF, S3 gallop

Front 27

Revised Cardiac Risk Index:

Back 27

6 Factors:
-high risk surgery
-hx ischemic heart dx
-hx CVA
-hx CHF
-preop use insulin
-preop serum creatinine >2.0

*>3 factors significant

Front 28

Low Risk Surgical Procedures:

Back 28

-Endoscopic procedures
-Superficial procedures
-Cataract
-Breast

Front 29

Intermediate Risk Surgical Procedures:

Back 29

-Carotid endarterectomy
-Head & Neck
-Intraperitoneal
-Intrathoracic
-Orthopedic
-Prostate

Front 30

High Risk Surgical Procedures:

Back 30

-Emergent major in elderly
-Aortic/Major Vascular
-Peripheral vascular
-Prolonged with large fluid shifts

Front 31

Major Clinical Predictors:

Back 31

-Unstable Coronary syndromes
-Decompensated CHF
-Significant arrhythmias
-Severe valvular disease

Front 32

Intermediate Clinical Predictors:

Back 32

-Mild angina pectoris
-Prior MI
-Compensated or prior CHF
-Diabetes Mellitus

Front 33

Minor Clinical Predictors:

Back 33

-Advanced age
-Abnormal ECG
-Rhythm other than sinus
-Low functional capacity
-Hx CVA
-Uncontrolled systemic HTN

Front 34

Functional Capacity:

Back 34

-Low: 1-3 METS: eating, dressing, walking around house
-Moderate: 4 METS: walk one flight stairs, walk at 4mph
-Excellent: >10 METS: swimming, tennis

*Less than 4 METS is a minor clinical predictor

Front 35

Ejection Fraction:

Back 35

-Normal: 60% or >
-Mild dysfunction: 59-40%
-Moderate dysfunction: 39-20%
-Severe dysfunction: 19% or less

Front 36

ECG

Back 36

-picture @ one moment in time
-detects acute changes
-old MI's
-hypertrophy
-arrhythmias
-conduction abnormalities

Front 37

2-D Echo:

Back 37

-Non-invasive
-assesses wall motion
-estimates EF
-estimates chamber size
-measures wall thickness
-can be inaccurate-depend on technician-when EF low can be <15%->28% inaccurate

Front 38

Exercise electrocardiography (Treadmill):

Back 38

-Increase demand to see if supply can keep up
-ischemia, arrhythmias, hypotension, syncope, MI, sudden deateh
-normal test does not exclude CAD

Front 39

Holter monitor:

Back 39

-Measures silent ischemia
-Records arrhythmias

Front 40

Exercise thallium:

Back 40

Give thallium, pt. exercises fluroscopy for infarcted areas

Front 41

Pharmacological Stress thallium:

Back 41

Pt. doesn't exercise, given adenosine and dipyridamole-dilate coronary's (produce coronary steal without direct negative inotropic stess testing)

Front 42

Coronary angiography:

Back 42

gold standard for evaluating CAD

Front 43

Significant ventricular dysfunction indicators:

Back 43

-EF <40%
-CI <2.2L/min
-LVEDP >18mmHg

Front 44

Beta Blocker Hemodynamic Effects:

Back 44

-Decrease contractility
-Decrease SA automaticity
-Decrease AV conduction

Front 45

Most sensitive leads for ECG:

Back 45

V4 & V5 90% sensitive
II & III 80% sensitive

Front 46

Ischemia:

Back 46

-<20min
-Peaked T Waves
-Inverted T Waves
-ST segment depression

Front 47

Injury:

Back 47

-20-40 minutes
-ST segment elevation

Front 48

Infarction:

Back 48

->1-2 hours
-Abnormal Q waves
->25% height of R wave in that lead
->2mm wide

Front 49

LAD occlusion on ECG:

Back 49

V1-V6

Front 50

Circumflex occlusion on ECG:

Back 50

I, aVL, possibly V5, V6

Front 51

RCA occlusion on ECG:

Back 51

II, III, aVF

Front 52

TEE

Back 52

Highest sensitivity for ischemia for intraoperative monitoring, only use intraoperative, expensive, analysis difficult