Unit 2: Myocardial Infarction (MI) Flashcards
1
Q
Acute Myocardial Infarction
A
destruction of heart muscle from lack of oxygenated blood supply
-common cause of obstruction = atherosclerosis
2
Q
Risk Factors for Heart Disease and MI
A
-cigarette smoking
-high LDLs
-type 2 diabetes
-elevated adrenaline (catecholamines)
-obesity
-inactivity
-hypertension
-male gender
-post menopausal female
-family hx
>can occur at any time
>most dangerous time = early morning hours; may be d/t higher levels of circulating adrenaline at this time
3
Q
Atherosclerosis
A
gradual build up of plaque inside the wall of the artery
- rupture of plaque = thrombus formation and obstruction of coronary artery flow = ischemia and death of heart muscle
- heart muscle damaged by inadequate blood supply cannot maintain normal cardiac function = decrease in cardiac output (CO)
- systemic symptoms associated w/ MI = chest pain and poor peripheral perfusion
4
Q
Stable Angina
A
episodes of intermittent chest pain present when artery is narrowed 60 to 70%
- associated w/ activity or exercise
- relieved by rest
- not associated w/ damage to heart muscle
- warning sign for potential heart muscle damage
5
Q
Acute Coronary Syndrome
A
umbrella term -used when there is concern for myocardial ischemia >unstable angina (UA) >non-ST elevation MI (NSTEMI) >ST elevation MI (STEMI)
6
Q
Unstable Angina
A
pain not associated w/ exercise
- not relieved by rest
- may present w/ ECG changes
- no elevation in cardiac markers
- may present w/ nonspecific or transient ST segment depressions or elevations
- emergency = requires immediate tx
7
Q
Non-ST elevation MI (NSTEMI)
A
partial occlusion of a major coronary vessel or complete occlusion of a minor coronary vessel
- causes reversible partial thickness heart muscle damage
- ST depressions (0.5 mm at least) or
- T wave inversions (1.0 mm at least)
- w/o q waves in 2 contiguous leads w/ prominent R waves or AR/S ratio > 1
- elevated cardiac markers
8
Q
ST Elevation MI (STEMI)
A
complete occlusion of a major coronary vessel
- results in irreversible full thickness heart muscle damage
- ST elevations
- elevated cardiac markers
9
Q
Clinical Manifestations
A
-Chest Pain (angina); from obstructed blood flow to the heart muscle
-Angina can be stable or unstable
>Stable (exertional) angina: occurs during activity, has predictable pattern, goes away w/ rest
>Unstable (rest) angina: more serious; can occur at rest w/ no specific pattern, not relieved by change in activity, medical emergency
-angina is a warning sign of impending MI
10
Q
Symptoms in addition to Chest Pain when there is a complete occlusion of the vessel resulting in an MI and muscle damage
A
- shoulder and arm pain (more on left)
- jaw and tooth pain
- shoulder blade pain
- upper back pain
- SOB
- nausea and vomiting
- sweating
- generalized fatigue
11
Q
Things to consider w/ person to person
A
- symptoms can vary significally from person to person
- women are more likely to have neck, shoulder blade, jaw, and abdominal pain
- diabetes are more likely to have SOB and fatigue
- geriatrics tend to have co-morbidities may mimic angina; may experience dyspnea, syncope, weakness, or confusion
12
Q
Right MI
A
right coronary artery/ventricle
- Jugular Vein Distention (JVD)
- Hypotension
- Bradycardia r/t damage to SA node
- Nausea and vomiting
13
Q
Left MI
A
left coronary artery/ventricle
-worse prognosis; high risk of sudden death and congestive heart failure
-dyspnea
-tachycardia
-hypertension
>tachycardia and hypertension result from the loss of CO b/c of damage to the left ventricle and subsequent stimulation of sympathetic compensatory mechanisms
-hypotension will quickly evolve
14
Q
Laboratory Testing
A
- Creatinine kinase (CK)
- Creatinine Kinase Myocardial Bands (CK-MB)
- Troponin (I and T)
- CMP, CBC, Coagulation, and ABGs
15
Q
Laboratory Testing: Creatinine Kinase (CK)
A
general marker of cellular injury
-released from cells in the brain, skeletal muscle, and cardiac tissue after muscle damage has occurred
16
Q
Laboratory Testing: Creatinine Kinase Myocardial Bands (CK-MB)
A
0-3 mg/dl
- CK isoenzyme marker specific to cardiac tissue
- when myocardial damage occurs, CK-MB is released from the cells
- can remain elevated for up to 36 hours before returning to normal
- increased levels can be seen at 3 hours after injury
17
Q
Laboratory Testing: Troponin (T and I)
A
proteins expressed almost exclusively in the heart; specific marker of cardiac muscle damage
-less than 0.4 mg/ml (<0.4 mg/ml)
-can elevate within 4 hours of injury
-levels can stay elevated for up to 10 days
(b/c it stays elevated longer than CK-MB, it is a valuable marker when attempting to diagnose injury in recent past
-blood test of choice
18
Q
Laboratory Testing: CMP
A
complete metabolic profile (CMP)
- electrolytes
- tests of organ system functioning (eg. Renal values: BUN + Creatinine)
19
Q
Laboratory Testing: CBC
A
complete blood count (CBC)
-tests hemoglobin, hematocrit, and WBC
20
Q
Laboratory Tests: Coagulation
A
- Prothrombin time (PT): 10-13 sec
- Activated Partial Thromboplastin Time (aPTT): 25-35 sec
- INR: <2.0
21
Q
Diagnostic Tests for MI
A
Invasive + Noninvasive
- ECG
- Echocardiogram
- Stress testing
- Coronary Angiography
22
Q
Electrocardiogram (ECG)
A
-gold standard for diagnosis of MI
-inexpensive, easy to perform, safe, painless
>ST depression = ischemia
>ST elevation = infarction
>Q wave = confirms MI (later on)
23
Q
Echocardiography
A
- used to evaluate the ventricular functions (ejection fraction [EF])
- assists in diagnosing an MI by looking at specific areas of heart muscle that are not contracting (wall motion abnormalities)
24
Q
Stress Testing
A
- not done during time an MI is evolving
- another way to evaluate heart function
- types: exercise stress test, dobutamine/adenosine test, stress echo, nuclear stress test
- dependent on pts needs and condition
- looks at coronary blood flow
- looks at left ventricular function and wall motion abnormalities
25
Nuclear Stress Test
best for diagnosing myocardial ischemia; reveals amount of viable heart muscle
26
Coronary Angiography
gold standard for the diagnosis of flow-limiting coronary artery disease
-allows visualization of any obstruction or narrowing of the coronary arteries
-involves catheter insertion into radial or femoral artery, and advanced up to the heart
-radiopaque dye injected through the catheter into the coronary artery while sequences of x-rays (fluoroscopy) are obtained
>a ventriculogram can also be performed; positioning the catheter to allow injected dye to enter the left ventricle; demonstrates how efficiently the left ventricle fills and pumps blood, how well blood flows through the aortic and mitral valves, and size of left ventricle
27
Treatment for MI
- maximizing oxygenation
- administering medications to control pain, dilate the coronaries, prevent clots, and decrease myocardial workload
- then therapies to increase blood flow to cardiac tissue, or reperfusion therapy (within 90 minutes)
28
Immediately upon arrival to the hospital, what should the patient recieve?
- Oxygen
- Sublingual (SL) nitroglycerin
- Aspirin
- Pain medication (morphine sulfate) if pain is not relieved by the SL nitroglycerin
29
Supplemental Oxygen
- recommended for all patients w/ a suspected MI
- used if in respiratory distress, if arterial saturation is less than 90%
- for patients w/ high risk of hypoxia
30
Nitroglycerin
dilates coronary arteries; increasing blood flow to the heart in an attempt to limit myocardial muscle damage and control pain
- one tablet sublingual q 5 minutes for a max of 3 doses as long as the patient maintains adequate BP
- if pain not controlled with 3 doses, IV nitroglycerin will be started
31
Aspirin
given to help prevent platelets from enlarging the existing clot or new clots from forming
32
Morphine Sulfate
can be given to control pain
- relieves chest pain
- masks pain symptoms; not improving coronary blood flow, potentially worsening MI
- used only if pain is not relieved by Nitroglycerin
33
Beta Blockers
>Metoprolol (Lopressor)
>Atenolol (Tenormin)
-to decrease sympathetic nervous system response
-decreases myocardial workload and myocardial oxygen consumption
-not used in right coronary artery MI experiencing bradycardia
34
Heparin
heparin sodium infusion
- helps prevent new clot formation
- anticoagulant
35
Commonly Prescribed Medications for MI
- Antiplatelet: Aspirin, Clopidogrel (Plavix), Eptifibatide (integrilin)
- Anticoagulants: Heparin, Enoxaparin (Lovenox), Factor XA inhibitors
- Narcotics: Morphine Sulfate, Hydromorphone (Dilaudid)
- Beta Blocker: Metoprolol (Lopressor), Atenolol (Tenormin)
- Nitrates: (Nitroglycerin)
- Thrombolytics: (Alteplase (Activase), Reteplase (Retavase)
36
Thrombolytics
>Alteplase (Activase)
>Reteplase (Retavase)
revascularization of the heart muscle by dissolving clots in arteries
37
Reperfusion Therapy
- Percutaneous Coronary Intervention (PCI)
| - Fibrinolytic Therapy
38
Percutaneous Coronary Intervention (PCI)
most preferred method for opening blocked vessels that cause MI
- done within 90 minutes of arrival to hospital
- catheter w/ small balloon on its tip is inserted into an artery (radial or femoral) and advanced under fluoroscopy up to the left side of the heart and coronary arteries
- balloon is inflated and deflated to open the lumen of the blocked artery
- lumen opened --> a stent may be advanced to the location to hold the artery open and maintain adequate blood flow
- risk of bleeding
- femoral approach: need to lie flat w/o bending leg for 2 to 6 hours to allow artery to heal
- radial preferred; risk for internal bleeding eliminated; external bleeding easily compressed
- radial artery catheter removal--> compression device placed; no requirement for pt to remain immobile
39
Fibrinolytics
medications that accomplish revascularization through fibrinolysis of the existing clot
- administered within 30 minutes of arrival to hospital
- considered if not contraindicated and immediate PCI not available
40
Contraindications for Fibrinolytics
- recent surgery or bleeding
- presence of peptic ulcer
- uncontrolled hypertension
- pregnancy
- non-compressible vascular punctures
41
Complications of Fibrinolytics
- bleeding
| - increased risk of intracranial hemorrhage
42
Coronary Artery Bypass Grafting (CABG)
surgical revascularization intervention that bypass blockages in the coronary arteries causing the myocardial muscle damage
-not first line; PCI and Fibrinolytics much quicker and do not require a surgical procedure
>in CABG, a healthy artery or vein is grafted to the blocked coronary artery; one end attached to the aorta while the other end is attached to the blocked coronary distal to the occlusion; by passing the blocked portion of the artery allowing blood to flow to the cardiac tissue
43
Indications for CABG
- unsuccessful PCI or not a candidate for PCI
- failure of medical management
- critical left main or 3 vessel disease
44
Complications of CABG
- bleeding
- dysrhythmias
- MI
- stroke
- nonunion of sternum
- sternal infection
- renal failure b/c of decreased renal blood flow
- heart failure
45
Complications of Bypass
- induction of a systemic inflammatory response resulting in vasodilatory shock
- heparin-induced thrombocytopenia
- activation of platelets
- complications associated w/ cross clamping the aorta during the procedure
46
Secondary Prevention
- cardiac rehabilitation after acute cardiovascular event (MI), percutaneous intervention, or surgical revascularization
- supervised exercise program
- education regarding diet, weight management, medication purpose and side effects, psychosocial support
- Goal: improve recovery from event; improve quality of life
- evaluated by cardiac specialists
47
Complications of MI
- Heart Failure
- Arrhythmias
- Cardiogenic Shock
48
Complication of MI: Heart Failure
when an MI causes a large amount of heart muscle to die, there is decreased left ventricular function
-inability to produce an adequate cardiac output (CO) to maintain body's metabolic demands
49
Complication of MI: Arrhythmias
>Asystole
>Symptomatic bradycardia
>Heart Block
>Ventricular arrhythmias
-asystole, symptomatic bradycardia, and heart block are associated w/ sinoatrial (SA) node dysfunction; most common after an inferior wall MI b/c the right coronary artery supplies the SA node (located in R atrium)
-temporary pacemaker may be used to prevent asystole
-ventricular arrhythmias occur in first 48 hours of MI
-immediate defibrillation tx of choice for v-fib and pulseless ventricular tachycardia
50
Nursing Management: Assessment + Analysis of MI
the clinical manifestations of MI is r/t lack of oxygen delivery to the heart and resulting decrease of cardiac output
- chest pain
- shortness of breath
- nausea/vomiting
- dizziness
- diaphoresis and pallor
51
Women may present w/ clinical manifestations of:
- neck, shoulder blade, and jaw pain
| - abdominal pain
52
Older Adults/ Geriatrics may show clinical manifestations of:
- dyspnea
- syncope
- weakness
- confusion
- pts can be tachycardic w/ borderline low BP
53
Nursing Assessments for MI
- Vital signs
- Pulse Oximetry
- Characteristics of Pain
- Assess ECG changes
- Assess for restlessness
- Skin color and temperature, diaphoresis
- Peripheral pulses
- Urine output
- Asses Troponin, CK, CK-MB Levels
54
Assessments: Vital Signs + Pulse Oximetry
-tachycardia w/ a borderline low BP and decreased Sp02 = inadequate CO and oxygen delivery (DO2)
55
Assessments: Characteristics of Pain
>location, radiation, duration, intensity, precipitating/alleviating factors
>use 1 to 10 pain scale
-chest pain is an indication of MI
-continued or changing pain characteristics can be indicative of a worsening condition
56
Assessments: ECG Changes
- ST-segment depression = ischemia
- ST segment elevation = injury
- if present, Q wave is diagnostic for MI
57
Assessment: Assess for Restlessness
- may be found in early stages of MI
| - progression to severe anxiety and sense of doom is a late-stage symptom
58
Assessment: Skin color, Temperature, Peripheral pulses, Diaphoresis
- decreased pulses and cold, clammy, pale skin
- signs of inadequate tissue perfusion and inadequate CO
- activation of the sympathetic nervous system w/ low BP will stimulate diaphoresis
59
Assessment: Urine Output
decreased or absent urine output is a sign of decreased renal perfusion r/t decreased CO
60
Assessment: Troponin, CK, CK-MB
>Troponin: protein released from damage cardiac muscle; elevates within 4 hours; can stay elevated for up to 10 days
>CK-MB: the CK isoenzyme marker specific to cardiac tissue is released from cells w/ cardiac muscle damage; increased levels seen at 3 hours; remain elevated for 36 hours
61
Post CABG Assessments
- Monitor HR and BP continuously w/ an arterial catheter at least q 15 minutes initially, then q 4 hours when stable
- Hemodynamic monitoring
- Continuous cardiac monitoring
- Assess heart tones
- Monitor breath sounds and continuous Sp02
- Monitor core temperature hourly
- Assess LOC, pupils and responsiveness
- Hourly intake and output
- Skin color, temperature, pulses, edema, capillary refill
- chest tube output, color, and volume hourly
- hemoglobin, hematocrit, electrolytes, creatinine and BUN, glucose
- incision for drainage, warmth, redness, or swelling
62
Post CABG Assessment: Monitor HR and BP w/ an arterial catheter q 15 min initially, q 4 hours when stable
-tachycardia, bradycardia, hypotension, or hypertension may be signs of decreased CO or compensatory mechanisms
63
Post CABG Assessment: Hemodynamic monitoring
-decreased preload (CVP, PAOP), Sv02 may indicate decreased CO; poor tissue perfusion
64
Post CABG Assessment: Continuous cardiac monitoring
-dysrhythmias common after CABG
65
Post CABG Assessment: Heart tones
- muffled may = tamponade
| - S3, S4 and crackles may = heart failure
66
Post CABG Assessment: Breath sounds and continuous Sp02 monitoring
- decreasing saturation may = pulmonary complications
| - diminished or unilateral absent breath sounds may = atelectasis, pleural effusions, or pneumothorax
67
Post CABG Assessment: Monitor core temperature hourly
- hypothermia during surgery reduces metabolic rate and risk of organ ischemia
- re-warming may produce hypotension from vasodilation
- core temp most reliable
68
Post CABG Assessment: Assess LOC, pupils and responsiveness
- assess effectiveness of sedation
| - evaluates neurological function
69
Post CABG Assessment: Hourly intake and output
- notify provider for output less than 30 ml/hr for 2 hours
| - decreased urine output may be a sig of renal damage or decreased CO
70
Post CABG Assessment: Assess skin color, temperature, pulses, edema, capillary refill
- pale, cool skin w/ delayed capillary refill and weak pulses may = decreased CO
- edema can be expected response after CABG r/t fluid resuscitation during surgery
71
Post CABG Assessment: Monitor Chest tube output, color, and volume hourly
-sudden increases in output greater than 100 to 200 mL not associated w/ position changes or increased bright red drainage may = hemorrhage and the need to return to OR
72
Post CABG Assessment: Assess Hemoglobin, hematocrit, electrolytes, creatinine and BUN, Glucose
- changes may indicate bleeding, fluid shifts, and renal dysfunction
- tight glucose control associated w/ improved outcomes
73
Post CABG Assessment: Assess incision site for drainage, warmth, redness, swelling
may = infection
74
Nursing Actions for an MI
-Administer oxygen
-Insert 2 large bore-IVs (medication delivery, fluid resuscitation)
-Administer medications:
>Aspirin and Heparin: prevent new clot formation
>Nitroglycerin SL: dilates coronary arteries; increasing blood flow and decreasing pain
>Morphine: narcotic given for pain relief if nitroglycerin not effective
>Beta Blockers: decrease sympathetic response to an MI, decreasing cardiac workload and oxygen consumption
>Fibrinolytics: work to dissolve clots
-Continuous ECG monitoring
-Bed Rest: to decrease oxygen and cardiac demands
75
Nursing Actions Post CABG
- Maintain tight BP control
- Administer fluids + Meds as ordered (vasodilators, vasoconstrictors, inotropes, and diuretics)
- Rewarm patients slowly w/ warm fluids, blankets, or airflow devices. Prevent shivering
- Administer pain medication and continuous sedation medication
- Pulmonary hygiene while intubated (reposition frequently, suction PRN, oral care q 4 hours)
- Pulmonary hygiene after extubation (incentive spirometry, cough and deep breathe q 1 to 2 hours while awake; chest splinting when coughing)
- Plan for and initiate early mobility or ambulation
- Wound Care: initial dressing to be removed or changed by provider, then change daily or PRN
76
Nurse Teaching for MI
- immediately report s/s of MI: chest pain, chest discomfort, or increased SOB
- purpose, dose, and side effects of meds
- AHA "Life's Simple 7"
77
Nurse Teaching Post CABG
- infection
- sternal precautions
- cardiac rehab
78
Sternal Precautions for Post CABG
- do not lift weight over 10 lbs
- do not raise arms overhead
- do not bend at waist
- do not participate in vigorous activity until cleared
79
Participate in Cardiac Rehab
- medical evaluation
- exercise training and physical activity counseling
- coronary risk factor reduction/secondary prevention
- nutritional counseling + weight management
- purpose of medications
- medication side effect
- effects on exercise tolerance
- reinforce medication adherence
80
Evaluating Care Outcomes
- free from pain
- normal vital signs
- improved Sp02
- signs of decreased perfusion from inadequate CO (cool extremities, weak pulses, decreased urine output) are resolving
81
AHA "Life's Simple 7"
1. No smoking of cigarettes or other tobacco products
2. Maintain normal body weight
3. Exercise for at least 150 minutes w/ moderate-intensity activity, or 75 minutes of vigorous-intensity or combo of both each week
4. Eat a healthy diet
5. Maintain total cholesterol less than 200 mg/dl
6. Keep BP less than 120/79 mmHg
7. Fasting glucose less than 100 mg/dl
