Exam #1 Flashcards
<p>CCUs/ICUs</p>
<p>* RRTs: rapid response teams
- pts exhibit subtle changes 6-8 hours before a cardiac or respiratory arrest
- critical care nurse, RT, MD, APN
- help diminish codes
* PCUs: transition between ICU and general care
- telemetry monitoring
* critically ill patient:
- physiologically unstable
- at risk for serious complication
- requires intesnsive and complicated nursing support
* ONLY for patients who are expected to recover </p>
<p>Common ICU problems</p>
<p>- venous thromboembolism due to immobility
- skin problems d/t immobolity
- hospital aquired infection HAI: many IV lines, vents, etc
- sepsis
- multiple organ dysfunction syndrome (MODS): systemic inflammation response
- nutritional deficiencies related to hypermetaolic or catabolic states: use enteral (GI system) route first, then parenteral if they have an illius, start nutrition within 3 days
- anxiety related to threat of physical health, foreign environment, pain, sleeplessness, immobilization, loss of control, impaired communication: work with pts, families, caregivers; encourage bringing personal items and photos; use antianxiety drugs (ativan); use massage/guided imagry
- pain due to medical conditions, immobilization, invasive monitoring devices and procedures: continuous IV sedation and analgesics; balanced anesthesia = neuromuscular blocking drugs and analgesics done every 1-2 hours in the ICU
- impaired communication due to use of sedative or paralyzing drugs, ET tube: always explain what is happening to pt, use picture boards, notepads, look directly at pt, use hand gestures, use interpreter, provide comforting touch, decrease meds when doing a neuro assessment
- sensory/perception prolems d/t delirium: assess for delirium with confusion assessment method for ICU an the intensive care delirium screening checklies; address physiologic factors (noises, decreased rest may cause delirium); encourage presence of caregiver; may need haloperidol
- sensory perceptual problems realted to sensory overload: be cautious with conversations, mute phones, set alarms appropriate to pts condition, limit overhead paging, limit unnecessary noises
- sleep problems d/t noise, anxiety, pain, frequent monitoring, treatment procedures: interrupted q 30-1hr for vitals and checks; structure the enviro to promote sleep wake cycle; cluster activities; schedule rest periods; limit noise; provide comfort measures; use benzodiazepines or zolpidem (ambien, be careful with this)</p>
<p>caregivers in the ICU</p>
<p>- give them guidance and support
- actively listen
- provide them with opportunity to participate in decision making
- involve durable power of attorney for health care if pt is incapable of making decisions
- give convenient access to the pt
- prepare caregivers for the ICU and the pts appearance
- provide option for caregivers presence during invasive procedures and CPR
- be culturally aware esp with death and dying</p>
<p>hemodynamic monitoring in the ICU</p>
<p>* measurement of blood pressure in veins, arteries, and heart, also measures blood flow and amount of ocygen in the blood
- invasive or non invasive monitoring
- can include: systemic and pulmonary arterial pressures, CVP (central venouse pressure), PAWP (pulmonary artery wedge pressure), CO/CI (cardiac output and index), SV/SVI (stoke volume and index), SaO2/SvO2, 02 sat
* integrating all this data together and trending provides a picture of how well the heart is working and how well tissues are being perfused
* very important to be technically accurate to prevent unnecessary or inappropriate treatment</p>
<p>preload</p>
<p>* preload = amount of blood in ventricle right before contraction; end of diastole
- PAWP: pulmonary artery wedge pressure, amount of blood in left side of heart; left ventricular end-diastolic pressure, left vent preload
- CVP: central venous pressure, right ventricular preload or right ventricular end diastolic pressure , amount of fluid in right side of heart, right vent preload
- PAWP &amp; CVP
- increased with: fluid overload
- decreased with: hypovolemia and vasodilation</p>
<p>invasive vs non invasive </p>
<p>- non invasive monitoring: Bp cuff, SpO2 monitor
| - invasive: arterial pressryres, CVP, PAWP</p>
<p>cardiac output &amp; cardiac index</p>
<p>* CO: volume of blood in liters pumped by the heart in 1 minute
* CI: measurement of the CO adjusted for body surface area; more specific to person; more precise measurement of efficiency of the heart's pumping action
- CO and the forces opposing blood flow determine BP
- increased with = high circulating volume, hypermetabolism with hypoxia
- decreased with = low circulating volume or decrease in strength of ventricular contraction (trauma, shock, sepsis, burns, massive vasodilation); 3rd spacing happens with decreased CO, decreased preload; massive MI causes decreased CO</p>
<p>stroke volume &amp; stroke volume index</p>
<p>- SV: volume of blood (MLs) ejected with each heartbeat; determined by preload, afterload, and contractility
- SVI: SV adjusted for BSA
- preload, afterload, and contractility determine SV (and thus CO and BP)</p>
<p>systemic vascular resistance &amp; pulmonary vascular resistance</p>
<p>- SVR: opposition encountered by the left ventricle
- PVR: opposition encountered by the right ventricle
- resistance of blood flow by the vessels</p>
<p>frank starlings law</p>
<p>- explains the effects of preload and state that the more a myocardial fiber is stretched during filling the more it shortens during systole and the greater force of the contraction
- increased preload = increased SV and CO = increased O2 demand to the myocardium</p>
<p>afterload</p>
<p>* afterload = forces opposing ventricular ejection, resistance the ventricle has to overcome to send blood to the body (SVR) or the lungs (PVR)
- resistence to properly circulate blood to entire body
- Systemic Vascular Resistance (left heart) or Pulmonary (right heart) = afterload
- when afterload is increased, CO is decreased
- increased SVR with: HTN, hardened arteries, CAD, low volume, catecholemines (fight or flight)
- increased PVR with: pulmonary HTN, right sided heart failure, hypoxia, PE
- decreased SVR with: vasodilators (morphine, nitrates), acidosis (blocks alpha and beta 1)
- decreased PVR with: oxygen, calcium channel blockers, aminophylline, isoproteronol</p>
<p>Sa02</p>
<p>- amt of 02 in arterial blood</p>
- normal: 93-100%
<p>Sv02</p>
<p>- how much 02 left in bood when it returns to the heart
- tells us if the body is using enough or too much 02</p>
- increased with: late sepsis (body alkolitic and wont release 02 to body), 02 improving in a patient, hemobloginb has tight grip on 02 and wont release
- decreased with: acidosis, hemoblobin has weak grip on 02 and it floats off, increased metabolic state, fever
- normal: 60-80%
<p>Sp02</p>
<p>- oxygen saturation
- % of hemoglobin with 02 on it</p>
- normal: 95-100%
<p>goals of hemodynamic monitoring</p>
<p>- maintain adequate tissue perfusion: early detection of changes, titration of therapy in unstable patients, determine what organ is causing a problem
- uses: shock, sepsis, any loss of cardiac function, burns, surgeries, hemorrhage, dehydration</p>
<p>PAWP</p>
<p>- pulmonary artery wedge pressure
- low PAWP = low volume/preload (fluid bolus, lopressors, helps titrate therapy)
- high PAWP = fluid overload (slow fluids even if low BP, vasopressors)</p>
<p>CO = HR X SV</p>
<p>- SV = preload, afterload, contractility
- preload: filling of ventricles
- afterload: resistance to properly circulate blood to body
- contractility: heart beat</p>
<p>ejection fraction</p>
<p>- measurement of the percentage of blood leaving your heart each time it contracts
- normal is 60-75%</p>
<p>CHF patients, example</p>
<p>- left sided systolic and diastolic issues
- systolic: problem with ventricles pumping = poor echocardiograms
- diastolic: preload, fluid issue, can't hold enough fluid but pumping is working fine = echo looks normal </p>
<p>contractility</p>
<p>* contractility = strength of contraction
- when increased: SV and o2 demand are increased
- increased with: positive inotropes (epi, norepi, isoproteronol, dopamine, dobutamine, digitalis), make heart fire off harder which increases contraction power
- deceased with: heart failure, alcohol, negative inotropes (calcium channel blockers, beta blockers), acidosis; slow HR and decreaesd BP cause decreased contractility </p>
<p>equipment needed for hemodynamic monitoring</p>
<p>* Intraarterial Catheter: 1 lumen, arterial
* central venous catheter: venous, single or multi lumen
* pulmonary artery catheter: venous, 4 or 5 lumens
- pressure bag: 1000 ml NS with a BP cuff around it; pump BP cuff up to 300 mmhg; 3-6mls/hr through art line
- 3-way stopcock: use this for "zeroing" to atmospheric pressure
- transducer: converts electrical activity into numbers on the monitor
- fast flush device: allows bolus of NS to go into atery and flush the line; makes sure you get accurate results</p>
<p>principles of hemodynamic monitoring</p>
<p>* at initiation and with every reading:
1) position pt supine or up to 45 degrees
2) leveling (to the heart) - positioning the zero reference point (stopcock nearest the transducer) to the phlebostatic axis (level at the right atrium), mark on the pt with a permanent marker (4th ICS, midaxillary line)
3) zeroing the transducer (to atmospheric pressure) - opening the reference stopcock to air, set the monitor to 0, close the stopcock to air and open to the patient
- obtain results at end expiration (respirations affect the reading)
* every shift:
- fast flush square wave test (dynamic response test) to ensure accurate wave forms
- ensure pressure bag is inflated to 300mmhg and infusing at 3-6ml/hr
* every 3 days: change pressure tubing, flush bag, and transducer</p>
arterial wave form
- systolic: uphill, depolarization, increased pressure
- dicrotic notch: aortic valve closes
- diastolic: downhill, repolarization, heart relaxes
- bolus dose, fast flush wave test
arterial lines
- purpose: continuous measurement of BP (systolic, diastolic, MAP), also allows frequent ABG/Blood sampling
- before insertion, ensure pt has positive allen test (shows proper circulation between radial and ulnar arteries)
- look for normal waveform: dicrotic notch (systolic pressure) shuld be after QRS on EKG
- complications: infection, impaired circulation, hemorrhage, emboli = monitor q 1 hr at least
Mean Arterial Pressure
- normal = 70-105
- most often used to assess perfusion
- more accurate than Bp alone since systolic BBP is affected by cent function and diastolic BP is affected by peripheral vasoconstriction
- tells us about blood flow to organs and tissues
- (diastolic x 2) + (systolic) divided by 3: 120/80 = 93 MAP
- needs to be greater than 60 to perfuse organs
central venous pressure monitoring
- CVP = right sided preload (filling) measure
- purpose: for pts with significant alteration in fluid volume, measures filling pressures of right side of heart
- placed in the subclavian vein, IJ, or femoral while in trendelberg position, may be asked to hold their breath, CVC is threated so that the tip rests in the superior vena cava
- single or multi lumen
- can give IV fluids and draw venous blood
- complications: tension pneumothorax, air embolus, thrombus, infection
CVP or right arterial pressure
- normal 2-8mmhg
- approximates right ventricle filling pressure (blood in right artium)
- tells us about right vent function and general fluid status
- increased with: fluid overload, right sided heart failure, pulmonary HTN
- decreased with: hypovolemia, decreased venous return (vasodilation, shock)
pulmonary artery catheter, Swan-Ganz
- tells us PAWP and PAP
- multiple ports
- right atrium/ventricle
- purposes:
- CVP/RAP monitoring (2-8mmhg)
- medication/ fluid admin
- blood sampling
- Sv02 (returned blood 02 sat)
- blood temp (increases with MI)
- CO thermo monitoring
- pulmonary arterial pressures
- pulmonary arterial wedge pressures (6-12mmhg)
- right atrium –> right ventricle –> pulmonary artery –> PAWP (upon inflation) and PAP (uninflated)
circulatory assist devices
- used temporarily or permanently to decrease vent work and improve end-organ perfusion
- used as: bridge to transplant (most common), destination thearpy for those who are ineligable for transplant, bridge to recovery
- requires no immunosuppression, but does require anticoags
- goal is to improve CO without increasing work of a failing heart
1) intraaortic balloon pump IABP: most common
2) ventricular assist device VAD
CAD, Intraaortic balloon pump IABP
- balloon is placed in descending thoracic aorta above the renal arteries
- balloon fills with helium at start of disatole and deflates before systole (triggered by close EKG monitoring), counterpulsation (inflates opposite to vent contraction, inflates with every heartbeat
- nursing care: heparain/anticoags, HOB
CAD, ventricular assistive decice (VAD)
- allows more mobility than IABP
- placed internally or externally
- takes blood from left artium or vent to the device and then to the aorta, may also be used to provide right heart support or biventricular support
- nursing care: has an external controller, odd heart sounds are normal, BP usually only by doppler, pulse ox may be inaccurate, CPR is often not sage, may need to be disconnected for defibrillation
- deccreases workload to the heart, blood is taken out of the body and flows through a machine
- cx: anemia, cirulatory issues
resting hemodynamic parameters
- Preload*
- central venous pressure/right atrial pressure: 2-8
- pulmonary artery wedge pressure/left arterial pressure: 6-12
- pulmonary artery diastolic pressure: 4-12
- afterload*
- MAP: 70-105
- PAMP: 10-20
- other*
- SV: 60-150
- SVI: 30-65
- HR: 60-100
- CO: 4-8L/min
- arterial hemoglobin 02 sat: 95-100%
- mixed venous hemoglobin 02 sat Sv02: 60-80%
- venous hemoblobin 02 sat: 70%
Coronary Artery Disease CAD
- a blood vessel disorder caused by atherosclerosis = hardening of plaque and arteries
- CAD is the most common type of CV disease
- other names: arteriosclerotic heart disease, CV heart disease, ischemic heart disease, coronoary heart disease
- usually rakes a long time to develop so impt to focus on people at risk and start treatment early
Acute Coronary Syndrome
- s/s of severe coronary artery disease CAD and includes unstable angina and myocardial infarction
atherosclerosis
- increased BP damages tissues, tears in the vessel wall form and inflammation cascade begins (increased plaque formaion in area of tear)
- foam cells build up, fibrin builds up but inflamm response is still going on underneath the fibrin buildup
- increased 02 demand will cause angina, MIs
- heart attack is when the clot breaks off and released throughout the body
collateral circulation
- influenced by genetic predisposition to angiogenesis and the presence of chornic ischemia
- it is helpful to the body
- no time for development of collateral circulation with rapid-onset CAD or coronary spasm leading to a big risk for MIs
- blockage forms but vessels grow around it to help increase blood flow
- may help when there is a blockage in the heart but wont prevent it
CAD risk factors
- non-modifiable: age, genger (higher incidence in males but more women die from it), ethinicity, family history, genetic
- modifiable: HTN > 160, tobacco use (1+ ppd), diabetes type II, high cholesterol > 200, physical inactivity, obesity, metabolic syndrome (HTN, other factors leading to insulin resistence), physiologic states (anxiety, stress increase HR and cause vessel damage), substance abuse
proper physical activity guidelines for CAD
- FITT
- frequency: most days of the week
- intensity: moderate, brisk walking, hiking, biking, swimming
- type: isotonic, increase healthy proteins and decrease insulin resistence
- time: 30 minutes
- adding resistence 2 days/week helps
Nutrition for CAD
- fat intake: 30% of calories (monounsaturated fats - decrease red meats, eggs, whole milk products)
- reduce or eliminiate alcohol and simple sugars
- take EPA and DHA supplements (turn to fatty acides which decrease cholesterol, omega 3s)
- increase omega 3 fatty acids (tofu, soybeans, fish, flax, walnut, canola)
- therapeutic lifestyle changes diet: low sat fat, low cholesterola, calories controlled by activity level, no absolute restrictions, no rules for coffee
cholesterol lowering therapy
- complete lipid profile q 5 years (start at age 20)
- diet therapy first: restrict calories to decrease weight, decrease dietary fat and cholesterol, increase physical activity
- reassess cholesterol levels after 6 weeks of diet therapy
- drugs are used concurrently with diet modification
- drugs are often needed for lifetime
- increased HDL = good, healthy
- decreased LDL = good, bad/increase cholesterol
cholesterol lowering drugs
- statins: inhibit cholesterol synthesis in the liver
- simvastatin - take meds at night when cholesterol peaks
- do not drink grapefruit juice!
- monitor AST and ALT for liver damage, side effect
- increase receptors in liver to breakdown cholesterol
- niacin: inhibits cholesterol synthesis
- many adverse effects: severe flushing, itching, GI problems, orthostatis hypotension
- take NSAID with this med to decrease side effects
- Lopid: fibric acid derivative, won’t affect LDLs
- affects vLDLs, targets coronary arteries
- may cause GI problems, interacts with many drugs
- Questran: welchol (bile acid sequestrants - increase conversion of cholesterol to bile acids
- bile acid is the product of cholesterol breakdown
- don’t give with any other meds, it will inhibit their effects
- give 2 hours apart from other meds
- zetia: inhibits absorption of dietary and bilary cholesterol
- often used with diet changes for primary hypercholesterolemia, works really well when combined with statins
antiplatelet therapy
- most people with cad should be on low-dose ASA (81mg): stops aggirgation of platelets in people with increased BP and atherosclerosis; side effects = GI bleeds; not as effective for women until >65
- for high risk women intolerant of ASA use plavix/clopidrogrel
- beware of GI bleeding and hemorrhagic stroke symptoms
gerontologic considerations, CAD
- although the incidence is high, risk reduction and CAD tx are worthwhile
- aggressively treat HTN, hyperliopidemia, and stop smoking
- planned physical activity: longer warm ups, longer peropds of low level activity, longer rest periods between sessions, avoid extreme temperatures (thinner skin, risk for dehydration)
Angina
- strangling of the chest
- temporary imbalance of 02 supple to the heart’s demand
- usually caused by stable, atherosclerotic plaque (people with high BP and cholesterol)
- doesn’t caused permanent change if unstable
- unstable: blockage getting worse and worse but some blood flow
- stable: MI
precipitating factors with angina
- physical exertion: with compromised supply of 02
- temperatue extremes
- strong emotions: stress, mad, excitement = increased work on heart and 02 demand
- eating a heavy meal: lots of blood needed in GI system and decreased 02 to heart
- tobacco use: catecholemines increase HR
- sexual activity: catecholemines
- stimulents: cocaine, amphetamines
- circadian rhythm patterns: more angina in the morning, body increase activy thgoughout the day
chronic stable angina
- chest pain that occur intermittently over a long period of time with the same pattern of onset, duration and intensity
- pressure, ache, constribitve, squeezing, NOT sharp or stabbing
- pain does NOT change with potiioning or breathing
- pain lasts 5-15 minutes
- may also have indigestion
- pain can radiate: around neck, back, mid chest
- usually controlled with rest of meds: nitro (vasodilator) can be take prophylatically before activity
other types of angina
- silent ischemia: ischemia without symptoms (diabetics can’t feel), will have shortness of breath and fatigue insteak, EKG diagnosis
- nocturnal angina: occurs only at night and they’re not sure why, not dependent on laying or standing
- prinzmetal’s angina: often occurs at rest, seen with migraines and raynaud’s syndrome, coronary spasms, need calcium channel blockers and/or nitrates - massive increase in calcium in vessels
- decubitus angina: only when laying down
Angina Diagnostic Tests
- 12 lead EKG: compare with previous testing, old MIs will show on current tests
- CXR: look for heart enlargement, calcifications, pulmonary problems
- labs: confirm CAD (triglyceride panel, protein levels (increased inflamm), HDL, LDL, vLDL, homocystine levels , look for risk factors
- if known CAD: echocardiogram (to see if drop in ejection fraction or not), exercise stress test (stable or unstable angina, blockage, EKG with exercise), cardiac cath (go in, look at arteries, stent if needed)
- chemical stress test: for elderly
- adenosine (small dose) stress test = increases HR
angina drug therapy, short acting nitrates
- short acting nitrates: 1st line tx
- SL, patch, spray, PO
- Glyceryl trinitrate (GTN) tablets or sprays, Isosorbide dinitrate
- should relieve pain in 3 mins and lasts 30-60 mins
- check BP, don’t give if less than 100
- 1 tab SL or 1 spray under tongue - may cause tingling, increased HR, headache, dizziness, flushing (vasodilation with increased ICP)
- if symptoms unchanged after 5 mins call EMS
- if symptoms improved after 5 mins, give max of 3 doesse and if not totally resolved after that then call EMS
- NEVER give if pt taking viagra
- monitor for ortho hypotension
- store away from light and heat
- replace q 6 months
- can take prophylacitcly before activity 5-10 mins
angina drug therapy, long acting nitrates
- isordil, Imdur
- used to reduce angina attacks
- caused headache, ortho hypotension, can cause tolerance
- nitropaste is dosed per inch on a flat muscular area with no hair or scars (works 3-6hrs, good for nocturnal and unstable angina)
- transdermal controlled-release by resevoir or matrix to maintain levels for 24 hours
- still take rapid/short acting for acute pain
- to decrease tolerance, on during day off at night
angina drug therapy
- bet blockers: preferred drug of choice for stable angina and following an MI
- metropolol, betalol, propanolol
- slows HR, heart works less, less 02 demand, less preload = decrease in heart demand
- side effects: low HR, low BP, wheezing, GI problems, wt gain, depression
- do NOT give if: HR
Angina treatment summary (ABCDEF)
- A = antiplatelet/anticoagulant, antianginal, ACE, ARB
- B = beta blocker, BP control
- C = cigarette smoking cessation, calcium channel blockers, cholesterol mngmt, cardiac rehab
- D = diet, diabetes, depression screening
- E = education, exercise
- F = flu vaccination (weakens heart muscle)
acute coronary syndrome ACS
- associated with deterioration of a plaque causing partial (UA, NSTEMI) or total (STEMI) occlusion by thrombus
- coronary arter disease –> chronic stable angina (slow) OR acute coronary syndrome (fast) –> Unstable angina/NSTEMI MI (small blood flow) OR STEMI (full occlusion)
unstable angina UA
- new chest pain, pain that occurs at rest, or pain that has a worsening pattern
- emergency!!
- unpredictable
- oftentimes women have prodromal (non-typical, no chest pain) symptoms (fatigue, dyspnea, indigestion, anxiety, back pain)
- men: more common to have big main artery blockages
- women: more common to have smaller vessel blockages
chest pain comparrison
- angina: onset/duration = sudden,
acute MI patho
- sustained ischemia >20mins causing irreversible myocardial cell death (4-6 hrs to necrose entire thickness of heart)
- due to thrombus
- most involve some portion of the left ventricle
- degree of preexisting collateral circulation influences the severity of the infarction
- 20+ mins = tissue death
- 4-6hrs = whole heart necrosis
- heart dies inside out
- collateral circulation may delay heart death
heart vessels
- left anterior descending artery LAD: widow maker, feed anterior portiono f heart
- circumflex artery: feed lateral and posterior portion of heart
- Right Coronary Artery RCA: feeds inferior portion of the heart
AMI s/s
- severe, immobilizing chest pain not relieved by rest, position change, nitrates or antacids
- more common in early AM, lasts > 20 mins, can be atypical
- sweating, ashen, clammy
- increased BP and HR (Drops later on)
- crackles (fluid in lungs backs up from heart)
- low MAP
- JVD, hepatic engorgement, edema, mimicks CHF
- n/v - stress response to pain
- tempt up to 100.4 (inflamm response)
- high glucose levels: fight or flight response from cortisol
- denial
- distant hearts ounds s3/s4
- dysrhythmias - sinus tachy with PVCs, T wave inversion, ST elevation or depression, abnormal q waves
- holosystolic murmor: interpapillary muscles die and valves malfunction
AMI healing process
- dead cardiac cells release enzymes: toponins, CKMG, norepi, epi
- leukocytes infiltrate, thinning the cardiac wall: inflamm process takes away dead tissue
- glucose and free fatty acids are released: cortisol release, increased glucose to supply ATP to heart
- can see the necrotic zone by ECG changes (st elevation, pathological q waves)
- 10-14 days later a weak scar develops, but the heart is very vulnerable
- 6 weeks after they are healed, but the scarred area is less compliant
- normal cells will hypertophy and dilate (vent remodeling) which can lead to heart failure
- ACE inhibitors help with prevention of ventricular remodeling by decreasing heart’s workload
dx studies for ACS
- serial ECGs (q 2-4hrs)
- change in QRS, ST segment and t wave
- distinguish between STEMIM (pathological Q wave) and NSTEMI or UA (incomplete occlusion without a pathological Q wave)
- look at pattern among the 12 leads to find the coronary artery involved
- ischemia causes ST depression, T wave inversion
- injury (still reversible) causes ST elevation
- infarction causes pathological Q wave and T wave inversion (occurs within hours, may be present for months0
- full blown occlusion/MI = STEMI with or without angina
- partial occlusion/MI = NSTEMI
normal EKG
- P wave: SA nodal depolarization; atrial depolarization
- PR interval: Depolarization travels from SA node through AV node via internodal pathway (getting to the AV node is quick!).
- QRS complex: ventricular depolarization (includes bundle branches & purkinje fibers)
- T wave: ventricular repolarization
- QT interval: total time the ventricles spend depolarized. Measured from beginning of QRS complex to end of T wave. (not shown).
- ST segment: The time between the end of the QRS complex and the beginning of the T wave. Along with the QRS complex, during this time the ventricle is in the absolute refractory period.
STEMI and NSTEMI
- STEMI: ST-segment elevation MI
- ST elevation, Pathological Q wave, T inversion
- complete occlusion of major coronary artery
- full-thickness damage to heart muscle
- NSTEMI: non-ST segment elevation MI
- ST depression, T inversion, NO pathological Q wave
- full occlusion of minor coronary artery or partial occlusion of major coronary artery
- partial thickness damage to heart muscle
- pathological Q wave: sign of a pervious MI, takes hours to develop
diagnostic cardiac markers
- all signify muscle death, CKMG and Troponin are cardiac muscle specific
- myoglobin is realeased earliest but not heart specific
- lab draws every 4-6 hours to keep track of levels
- if ECG and cardiac markers are non-diagnostic: exercise or pharm stress test, echo, stress echo
1) CKMG: increases within 4-6 hours of MI, peaks within 18 hours, normal within 24-36 hours
2) troponin: increases 4-6 hours within MI, highest specificity to MI, peaks within 10-24 hours, takes 2 weeks to normalize
3) myoglobin: released very fast, not cardiac specific but muscle death in general
AMI tx
- establish an IV
- give 02 (2-4 liters by NC), position upright, heart has increased 02 demands
- 12 lead EKG, continuous monitoring
- aspirin, SL nitro (decreased preload, decrease workload of heart, vasodilate)
- morphine IV is pain not relieved by nitro
- treat dysrhythmias
- VS with pulse ox frequently
- bedrest for 12-24 hours
- SPO except sips of water (potential testing)