Hemodynamics Flashcards
(180 cards)
1
Q
The term used to describe the forces and mechanics of blood flow
A
Hemodynamics
2
Q
The measurement and monitoring of the factors that influence circulation
A
Hemodynamic monitoring
3
Q
Volume of blood ejected by the heart over 1 minute
A
Cardiac output (CO)
4
Q
CO normal range
A
4-8 L/min
5
Q
The volume of blood ejected from the ventricle with each beat of the heart
A
SV
6
Q
What are the 3 components of stroke volume?
A
Preload, afterload, contractility
7
Q
CO value adjusted for body size (BSA) that provides a more accurate measurement of adequacy of circulation
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Cardiac Index (CI)
8
Q
CI normal range
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2.5-4 L/min m2
9
Q
Equation for CI
A
CI = CO/patient’s BSA
10
Q
BSA is calculated through what measurements?
A
Weight (Kg) and Height (cm)
11
Q
Goal of hemodynamic monitoring
A
Tissue perfusion
12
Q
To perfuse tissues and organs, several things must be done including
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1) get O2 into lungs (ventilation), 2) get O2 from lungs into tissues (oxygenation), 3) get oxygenated blood to tissues (circulation), and 4) release O2 from blood into tissues
13
Q
Factors that affect CO
A
Preload, afterload, contractility, and HR
14
Q
Factors resulting in low cardiac output
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Low SV, Low HR, or Both
15
Q
Factors that decrease stroke volume
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Low preload, high afterload, or decreased contractility
16
Q
Component of stroke volume concerned with volume
A
Preload
17
Q
Preload is associated with
A
Venous vasoconstriction or vasodilation
18
Q
The initial stretching of cardiac myocytes prior to contraction
A
Preload
19
Q
Preload is measured as ___ in the right ventricle and ___ in the left ventricle
A
CVP; PCWP/LVEDV
20
Q
Factors that increase preload
A
Increased blood volume, pregnancy, exercise, HF, valve regurgitation, increased ventricular compliance
21
Q
Factors that decrease preload
A
Drugs such as venous vasodilators and diuretics, loss of AV synchrony, increased HR
22
Q
Volume of blood in the left ventricle at the end of diastole, as systole begins
A
LV end-diastolic volume
23
Q
The ability of the heart and lungs to stretch
A
Compliance
24
Q
How do venous vasodilators decrease preload?
A
Reduce blood return to the R side of the heart
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How do diuretics decreased preload?
Reduce overall volume
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Direct measure of preload
CVP
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Premise that the greater the end-diastolic volume (preload), the greater the stretch of muscle cells, leading to greater stroke volume up to a point
Starling’s Law (Frank-Starling Curve)
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Component of stroke volume associated with resistance
Afterload
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Afterload is associated with
Arterial vasoconstriction or vasodilation
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The pressure that must be overcome to push blood into the aorta or “what the heart has to work against”
Afterload
31
Factors that increase afterload
Vasoconstriction (medications with alpha 1 properties), hypothermia, SNS activation, aortic/pulmonic valve stenosis, HTN (systemic or pulmonary)
32
Factors that decrease afterload
Arterial vasodilation resulting from fever, exercise, inflammation/infection, or medications
33
Medications that cause arterial vasodilation (decreased afterload)
ACE inhibitors, ARBs, CCB, hydralazine (Apresoline), nipride, NTG
34
Afterload is measured through ___ in the right ventricle, and ___ in the left ventricle
CVP; PCWP
35
Explain resistance
The smaller the vessel the greater the resistance and vice versa; the greater the resistance, the harder the heart has to work to eject blood; increased resistance increases cardiac workload
36
Factors causing vasoconstriction
Decreased temperature, SNS activation, medications such as alpha — epi, phenylephrine, Levo (norepinephrine), vasopressin
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Intervention to decrease afterload
Arterial vasodilators
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Hormone that helps regulate BP by constricting blood vessels and triggering uptake of sodium and water
Angiotensin
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Effects of increased afterload
Increased cardiac workload and oxygen
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What should be administered to a smoker with HTN with narrowed, stiffened arteries?
Arterial vasodilator due to increased afterload
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The force the heart can generate to eject blood, or the ability of the heart to overcome afterload
Contractility
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Factors that increased contractility
SNS activation (catecholamine release), drugs
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Factors that decrease contractility
PNS stimulation, hypoxia, ischemia/injury/infarction, acidosis, electrolyte imbalances
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Irreversible tissue death from prolonged ischemia
Infarction
45
A patient with hypoxia and ischemic chest pain may have decreased
Contractility
46
Drugs that increase contractility
Digoxin, dopamine, dobutamine, epi
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Drugs that decrease contractility
Negative inotropes such as beta blockers
48
The percentage of blood ejected from the ventricle
Ejection fraction (EF), or Left Ventricular Ejection Fraction (LVEF)
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Ejection Fraction equation
EF = SV/LVEDP x 100
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Normal EF
55-75%
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Normal EF in women and men
Slightly higher for women (54-74%) than men (52-72%)
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Low EF resulting in decreased ventricular function is associated with what conditions?
MI, CM, ischemia
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Higher EF is associated with heart conditions like
Hypertrophic cardiomyopathy
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EF less than 40% is generally considered
HF
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Purpose of hemodynamic monitoring
Early detection, identification, and treatment of life-threatening conditions; evaluation of patient’s response to treatment; evaluate effectiveness of cardiovascular function
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Indications for hemodynamic monitoring
Determine fluid volume status, measure CO, monitor/manage unstable patients, assess hemodynamic response to therapies, Dx primary pulmonary HTN, Dx shock states
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Types of hemodynamic monitoring
Non-invasive, direct measurement of arterial pressure, invasive
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Non-invasive hemodynamic monitoring includes
Clinical assessment and NBP
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Non-invasive hemodynamic monitoring through clinical assessment
skin color/temp/mottling, HR, pulses, mental status, cap refill, UO, pulse ox, edema
60
Disadvantage of non-invasive hemodynamic monitoring
Susceptible to inaccuracy related to nature of measurements, impact of patient condition on results, etc.
61
Automated BP is less accurate during
Hypotension, arrythmias
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Inaccurate pulse ox reading may be influenced by
Vasoconstriction, poor perfusion, cold extremities, skin pigmentation, motion artifact
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A blood pressure cuff that is too small may yield a false _____ reading, while a blood pressure cuff that is too large may yield a false _____ reading
High; low
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Indications for arterial BP monitoring
Frequent titration of vasoactive drips, unstable BP, frequent ABGs or lab draws, inability to obtain noninvasive BP
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Sites for arterial BP monitoring
Radial, brachial, and femoral artery
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Complications of arterial blood pressure monitoring
Hematoma, blood loss, thrombosis, distal ischemia, arterial injury, infection
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Arterial line must remain level with patient’s
Phlebostatic axis (4th intercostal space, mid-axillary line)
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An arterial line transducer that sits too low can result in a false _____ pressure, while a transducer that sits too high can result in a false _____ pressure
High; Low
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Purpose of zeroing an arterial line transducer
Eliminates atmospheric pressure (0 mm Hg) ensuring that pressure measurements reflect only pressure values from the patient
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Calculated pressure that closely estimates the perfusion pressure in the aorta representing average systemic arterial pressure during the entire cardiac cycle
Mean Arterial Pressure (MAP)
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Normal MAP
70-100 mm Hg
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MAP must be maintained above ___ mm Hg to preserve perfusion of major organs
60
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Nursing implications for arterial line
Prevent/reduce potential complications, maintain 300 mm Hg on pressure bag, maintain continuous flow through tubing, aseptic dressing changes, sterile caps on openings
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How often should arterial line tubing be changed?
Every 96 hrs or per facility protocol
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How often should arterial line fluids be changed?
Every 24 hours (NS or heparin 1000 units/500 mL)
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The nurse should hold the discontinued arterial line site for at least
5 min
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Why does arterial line tubing need to be changed every 96 hrs?
To decrease opportunity for contamination of closed system
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Why is heparin not commonly used in an arterial line?
Risk of HIT
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Measurement of right atrial pressures reflecting preload to the right side of heart
Central Venous Pressure (CVP)
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CVP assesses
Blood volume and RV function
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CVP normal range
2-6 mm Hg
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Causes of low CVP
Inadequate preload, hypovolemia (or bleeding), vasodilation
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Causes of high CVP
Hypervolemia, RV failure, cardiac tamponade, tricuspid valve disease, pulmonary HTN, chronic LV failure, ventricular septal defect, constrictive pericarditis, PEEP > 10
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CVC/PAC nursing care
Sterile insertion and dressing changes, hand hygiene, avoid kinking, periodic flushing for patency, maintain sterile port, prompt removal if no longer required, NOT routinely replaced, replace tubing every 96 hrs, monitor for infection
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Hand hygiene is the most crucial step in nursing care for CVC to avoid
HAI such as CLABSI
86
Why are CVCs not routinely replaced?
Risk of complications and infections
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CVC ports nursing care
Vigorous scrubbing before use (CHG, alcohol), use only sterile devices to access, lumens capped at all times
88
Placement of swan gang (pulmonary artery) catheter
Internal jugular vein, subclavian vein, femoral vein
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What does a swan ganz catheter measure?
Pulmonary artery pressure (PAP), central venous pressure (CVP), core body temp, and allows for measurement of CO
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Where does the tip of the swan ganz catheter lie?
Pulmonary artery
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Indications for PA catheter
Dx and management of PAH, HF management, shock differentiation
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Pulmonary artery pressure (PAP) normal range
20-30 / 6-12 mm Hg
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Reasons for increased PAP
L-sided HF, increased pulmonary blood flow, increased pulmonary arteriolar resistance
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Reasons for decreased PAP
Hypovolemia, increased pulmonary resistance (ex: pulmonary HTN)
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Normal range for wedge pressure (PAWP/PCWP)
4-12 mm Hg
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Indirect measure of left atrial filling pressure
Wedge pressure (PAWP/PCWP)
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What does PAWP/PCWP indicate?
Intravascular fluid volume status
98
Wedge pressure should be roughly equal to
Left ventricular end diastolic pressure (LVEDP)
99
Why should PAP and PAWP be measured at end-expiration?
Respiratory pressure changes (ventilation) affect PAP and PAWP; intrathoracic pressure approaches atmospheric pressure and has the least effect on hemodynamic pressures at end-expiration
100
Swan and Wedge ports should be inflated with no more than ___ mL of air
1.5
101
How is wedge pressure measured?
By advancing a PA or swan ganz catheter in small branch of pulmonary artery
102
PA catheter puncture site complications
Infection, hematoma, bleeding, pneumothorax (IJ/SCV access)
103
PA catheter rhythm disorder complications
PAC/PVC, VT, VF
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PA Catheter conduction disorders complications
Right bundle branch block (particularly danger in preexisting LBBB)
105
PA catheter complications
Damage to pulmonic or tricuspid valve (caused by pullback with inflated balloon), pulmonary artery rupture, pulmonary infarction/thromboembolism
106
Measures of preload
CVP, wedge pressure, PAD
107
Measures of afterload
ABP, SVR, PVR, valvular dysfunction
108
Measures of contractility
LVEF, RVEF
109
PAD can be a substitute measure for preload EXCEPT in patients with any degree of
Pulmonary hypertension (ex: smokers)
110
How does a defibrillator work?
randomized shock delivery to myocardium making all electrical activity stop. Goal is that patient’s own pacemaker will kick in and restore a normal rhythm
111
Defibrillators that decrease the amount of energy needed to convert rhythm resulting in less myocardial damage
Biphasic (150j - 200j)
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Monophonic defibrillator range
200j - 360j
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Shock synchronized with the patient’s R wave on EKG to avoid delivery of electricity during the refractory or repolarization phase
Cardioversion (synchronized shock)
114
Indications for cardioversion
Convert arrhythmias back to Sinus Rhythm, used for rapid rhythms WITH pulse (SVT, Afib, Aflutter, VT (pulse))
115
What causes ventricular tachycardia?
Low magnesium level
116
Preparing the patient for cardioversion
Ensure understanding, remove all metal objects from pt to prevent burns, do not shock over transdermal medication (remove or avoid), ensure pt and environment dry, remove hair from chest if necessary, confirm asystole in 2 leads; no need to turn to side
117
Defibrillator pad placement
To right of sternum just below clavicle, to left anterior axillary line 5th-6th intercostal space; NOT placed over permanent pacemaker
118
Additional patient preparation for cardioversion
Informed consent, time-out, obtain 12-lead EKG, NPO, supine position, remove dentures/partial plates, pre oxygenate and maintain oxygenation throughout procedure (NRB or oxymask; ambu-bag on standby), ensure suction set up, sedation and analgesia as prescribed, set defibrillator on “synchronize”
119
Synchronizing a defibrillator
Synchronized to R wave of patient’s EKG rhythm; marker indicates synchronization and beeping sound for each R wave (note: this procedure hurts!)
120
Post defibrillation care
Assess VS, LOC, pulmonary and cardiovascular status; antidysrhythmic meds if needed; evaluate for burns; emotional support
121
Treatment of choice for ventricular fibrillation (VF) and pulseless ventricular tachycardia (VT)
Defibrillation
122
Synchronized v. Unsynchronized defibrillation for V -tach
Stable v. Unstable
123
Defibrillator strips for ventricular tachycardia vs. ventricular fibrillation
Monomorphic for VT and fine VF
124
Post unsynchronized shock monitoring and care
Evaluate LOC, VS, burns, and electrolytes; monitor airway (may be intubated during code), IV fluids (vasopressors for BP) antidysrhytmic medications (IV drip, amiodarone), consider possible causes
125
Defibrillation education
Explain S/S and problems associated with the dysrhythmia, discuss need for long term drug therapy, lifestyle changes, possible implanted cardiac defibrillator (ICD), need for an emergency communication system
126
Types of pacemakers
Transdermal, transvenous, epicardial, permanent
127
Transdermal pacemaker
Emergency, painful, very temporary
128
Transvenous pacemaker
Temporary, usually via IJ or femoral vein, sits in RV
129
Epicardial pacemaker
After cardiac surgery, use gloves to handle
130
What should patients with pacemakers avoid?
Strong magnets (turn off pacemaker and stop function), MRI
131
Permanent pacemaker
For complete heart block or other severe blocks, single/double/or triple chamber options, few restrictions after recovery (exercise, sexual activity, etc. are OK)
132
Permanent pacemaker post-procedure care
CXR, Monitor for bleeding/swelling at insertion site, pain/comfort, and assess EKG for appropriate function
133
Function of implantable cardiac defibrillator (ICD)
Shocks the patient internally for VT or VF
134
ICD education
OK to do chest compressions, magnet turns off defib (no MRI w/o consult), can have pacemaker and defib in one (most ICDs are also pacemakers), batteries replaced in several years (~10)
135
Where to listen during cardiac assessment
Aortic area, pulmonic area, Erb’s point, tricuspid area, mitral area/apex
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Aortic area
2nd intercostal space, right sternal border
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Pulmonic area
2nd intercostal space, left sternal border
138
Erb’s point
3rd intercostal space, left sternal border
139
Tricuspid area
4th intercostal space, left sternal border
140
Mitral area/Apex
5th intercostal space, midclavicular line
141
Area in which S2 (dub) sound is loudest
Aortic area
142
Area in which S1 (lub) sound in loudest
Mitral area
143
S2 (dub) sound is associated with
Closure of pulmonic and aortic valves
144
S1 (lub) sound is associated with
Closure of mitral and tricuspid valves
145
S3 heart sound
Follows S2, ventricular gallop (“Ken-tuck-y”), common in children, cardinal sign of HF, pulmonary edema, atrial septal defect
146
S4 heart sound
Occurs just before S1, Atrial gallop (“ten-nes-see”), indicates increased resistance to ventricular filling, MI after effect, elderly, HTN, aortic stenosis
147
Murmurs are caused by
Turbulent blood flow (d/t stenosis, regurgitation, structural defects such as septal defects, ruptured papillary muscle, etc.)
148
Assessment of abnormal or extra heart sounds
Location, degree (loudness), character, timing
149
Extra heart sounds
S3 and S4
150
Extra heart sounds indicate
Decreased ventricular compliance to filling
151
Extra heart sound associated with early diastole (passive filling phase)
S3
152
Extra heart sound associated with late diastole (caused by blood in active filling phase working against higher pressure (non-compliant LV))
S4
153
Best way to hear abnormal or extra heart sounds
With bell of stethoscope (low-pitched sound), patient on L side
154
Flow of blood through a valve that is supposed to be open, but is narrowed d/t calcium, clots, congenital defects, etc.
Stenosis
155
Backward flow of blood through a valve
Regurgitation
156
Regurgitation characteristics
Blowing, harsh, musical sound
157
S3 may be normal in patients…
Under 40 or some athletes (should disappear before middle age)
158
S4 is nearly always
Pathologic
159
Pulses to assess
Carotid, brachial, radial, ulnar, femoral, popliteal, posterior tibial, dorsalis pedis
160
Assessment of pulses
Note symmetry and strength, start distal and move up if not felt, if you think you feel it —> confirm w/ Doppler
161
Indications of poor CO and tissue perfusion
Cyanosis, pallor, cold skin
162
Characteristics of arterial insufficiency
Skin cool, pale, and shiny; ulcerations on toes and heels; foot usually turns deep red when dependent; nails may be thick and ridged
163
Characteristics of chronic venous insufficiency
Ulcerations around ankles, foot cyanosis when dependent, edema
164
Visible JVD can indicate
R-sided HF (occurs any time venous return is greater than hearts ability to pump the blood back out)
165
Partially occluded blood vessels
Bruits
166
Assessment of carotid artery bruit
Auscultate upper, middle, and lower carotid artery; have patient hold breath while auscultating each spot (eliminates high tracheal breath sounds)
167
Factors for monitoring perfusion
Noninvasive BP, HR, pulses, mental status, skin temp, mottling, cap refill, UO, pulse ox
168
Structures responsible for nutrient and oxygen delivery
Arteries and capillaries
169
Characteristics of ischemia
Blood is available but reduced (thrombus, stenosis, vasospasm), always results in hypoxia, leads to pain
170
Reduced oxygenation (turning blue) as a result of uncorrected ischemia
Hypoxia
171
Total lack of oxygen in body tissues resulting in cell death (infarction)
Anoxia
172
Insufficient flow of oxygenated blood to tissues that may result in hypoxia and subsequent cellular injury and death
Ischemia
173
The death of tissue with an inability to regenerate
Infarction
174
The death of an area of heart muscle or myocardium
Myocardial infarction
175
Chest pain assessment scale
APQRST: associated symptoms, palliative/provoking, quality (dull/sharp/crushing), radiate, severity (0-10), timing (before/after exercise, etc.)
176
Cardiac laboratory testing for diagnosis
Enzymes such as CK, CK-MB; troponin (elevation indicates MI/infarction); BNP (elevation indicates HF)
177
Laboratory tests for cardiac risk factors
Cholesterol/lipids (HDL/LDL), triglycerides
178
Cardiac enzyme that measure possible brain, heart, skeletal mm injury
CK
179
Cardiac enzyme specific to cardiac injury
CK-MB
180
Peptide that helps regulate circulation by promoting urine excretion, relaxing blood vessels, lowering BP, and reducing cardiac workload
BNP
