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31 Cards in this Set
- Front
- Back
Normal Sinus Rhythm
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indicates that the rate is between 60 and 100, inclusive, and that the P waves are identifiable and are of the same morphology throughout. The RR interval or PP intervals between beats are same.
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CO = SV X HR
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HR 80/min: CO=SV x HR = 65 x 80= 5200
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Cardiac Index
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A cardiodynamic measure based on the cardiac output, which is the amount of blood the left ventricle ejects into the systemic circulation in one minute, measured in liters per minute (l/min). Cardiac output can be indexed to a patient's body size by dividing by the body surface area (called the BSA) to yield the cardiac index.
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Stroke volume
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is the amount of blood pumped by the left ventricle of the heart in one contraction.
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Preload
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is the pressure stretching the ventricle of the heart, after passive filling and atrial contraction. If the chamber is not mentioned, it is usually assumed to be the left ventricle.
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Afterload
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is used to mean the tension produced by a chamber of the heart in order to contract. If the chamber is not mentioned, it is usually assumed to be the left ventricle. However, the strict definition of the term relates to the properties of a single cardiac myocyte. It is therefore only of direct relevance in the laboratory; in the clinic, the term end-systolic pressure is usually more appropriate, although not equivalent
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Frank-Starling's Law
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states that the more the ventricle is filled with blood during diastole (end-diastolic volume), the greater the volume of ejected blood will be during the resulting systolic contraction (stroke volume).
preload |
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P Wave
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It records the electrical activity of the heart's two upper chambers (atria).
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QRS Wave
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records the electrical activity of the heart's two lower chambers (ventricles)
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T Wave
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It records the heart's return to the resting state.
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SA Node
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anatomical pacemaker
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SA Node: P wave
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Under normal conditions, electrical activity is spontaneously generated by the SA node, the physiological pacemaker. This electrical impulse is propagated throughout the right and left atria, stimulating the myocardium of the atria to contract. The conduction of the electrical impulse throughout the atria is seen on the ECG as the P wave
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AV node/Bundles: PR interval
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The AV node functions as a critical delay in the conduction system. Without this delay, the atria and ventricles would contract at the same time, and blood wouldn't flow effectively from the atria to the ventricles. The delay in the AV node forms much of the PR segment on the ECG. And part of atrial repolarization can be represented by PR segment.
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Purkinje fibers/ventricular myocardium: QRS complex
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The two bundle branches taper out to produce numerous Purkinje fibers, which stimulate individual groups of myocardial cells to contract.
The spread of electrical activity through the ventricular myocardium produces the QRS complex on the ECG. |
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Ventricular repolarization: T wave
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The last event of the cycle is the repolarization of the ventricles
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Normal sinus rhythm
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An impulse (action potential) that originates from the SA node at a rate of 60 - 100 beats/minute (bpm)
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Ventilation/Perfusion VQ
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Ventilation is defined as the flow of air into and out of the alveoli.
Perfusion is defined as blood flow to the alveoli. |
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Gas exchange in the lungs
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The lungs are composed of about 300 million alveoli that are capable of gas exchange. Gas is exchanged between the blood and the air. Thus, it depends on both ventilation and perfusion.
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Ventilation/Perfusion Inequality
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To be the most efficient, the right proportion of alveolar air flow (ie.ventilation) and capillary blood flow (perfusion) should be available to each alveolus. Any mismatch is called ventilation-perfusion inequality. In an ideal lung, the V/Q ratio=1, ie. they are equal (V= ventilation and Q = perfusion).
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O2
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The major effect of any ventilation-perfusion inequality situation is that it lowers the PO2 of systemic arterial blood. In other words, the O2 in the alveoli will remain much higher than the O2 in the arterial blood.
In fact, in the body, PO2 of arterial blood is always about 5mmHg lower than PO2 in the alveolar air. |
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Tidal Volume
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Volume inspired or expired with each normal breath.
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Residual volume
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Volume that remains in the lungs after a maximal expiration. CANNOT be measured by spirometry
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FUNCTIONAL RESIDUAL CAPACITY (FRC):
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Volume of gas remaining in lung after normal expiration, cannot be measured by spirometry because it includes residual volume:
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VITAL CAPACITY (VC):
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Volume of maximal inspiration and expiration
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TOTAL LUNG CAPACITY (TLC)
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The volume of the lung after maximal inspiration. The sum of all four lung volumes, cannot be measured by spirometry because it includes residual volume:
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Hyponatremia
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s/s: Anorexia, nausea, vomiting, headache, lethargy, confusion, muscle cramps
char: serum na+ <135 mEq/L, interv: monitor I&O, urine gravity, encourage diet high in Na+ |
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Hypernatremia
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s/s: Thirst, inc. body temp. sticky mucous membranes, hallucinations, seizures
Serum Na+>145 mEq/L interv: monitor for fluid loss & lrg gains of sodium, offer fluids, monitor food sodium |
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Hypokalemia
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s/s: Fatigue, anorexia, nausea and vomiting, K+ loss, heavy diaphoresis- use of K+ wasting drugs, steriod admin
char: serum k+<3.5 mEq/L, ABGs show alkalosis ECG show flattened T-wave & depressed ST segment interv:assess digitalized clts for symptoms of digitalis toxicity K+ suppliments if needed Prev: encourage extra K+ intake, |
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Hyperkalemia
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decreased K+, renal failure, caused from acidosis, burns, tissue trauma
char: serum K+>5.0 mEq/L, ECG shows peaked T wave and widened QRS, absent P wave, vague muscle weakness, diarrhea, GI hyperactivity, nausea, cardiac arrhythmias, interv: monitor cardiac status, admin diuretics, glucose, insulin, hold K= supplements , monitor serum K+ levels, life-threatening,avoid foods high in K |
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Hypocalcemia
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hypoparathyroidism, malabsorption, vit D defi., acute pancreatitis, sepsis,
char: serun CA++<8.5, numbness, tingling, fingers toes, hyperactive deep tendon reflexes, muscle tremors, ECG show prolonged QT interval, Chvostek's sign, Trousseau's sign inter: take seizure precautions when severe, monitor airway closely, take safety precaut.for confusion, |
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Hypercalcemia
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hperparathyroidism, prolonged immobility, megadoses of vit D, bone malignancy, Paget's disease,
char: serum Ca++ >10.5, ECG shows shortened QT interval, lethargy, weakness, NVC, decreased memory ande attention span, confusion, cardiac arrest interv: keep clt well hydrated, discourage excessive milk products, safety prec. for confusion, adequate fiber, be prepared for cardiac arrest, careful because of weakened bones, cranberry or prune juice, encourage mobility |