What is the pathway of blood flow through the heart?
- Inferior Vena Cava, Superior Vena go into the
- Right atrium to the
- Tricuspid Valve to the
- Right Ventricle out the
- Pulmonary semilunar valve into the
- Pulmonary arteries to the
- Lungs and then out of the
- Pulmonary veins into the
- Left atrium and through the
- Mitral (bicuspid valve) into the
- Left ventricle and then through the
- Aortic valve into the
- Aorta and then through the
- Arteries and then the
- Capillaries and meets up with the
- Veins and all venous blood dumps into the
- Inferior vena cava, superior vena cava
What is blood pressure?
Pressure in the systemic arteries which is created by the ejection of blood from the left ventricle.
What factors affect BP?
Cardiac output and systemic vascular resistance
What is the Mean Arterial Pressure (MAP)?
Reflects the average or mean arterial pressure in the blood perfusing the organs. Changes in MAP are related to the dynamic relationship between cardiac output and systemic vascular resistance
What does a low MAP indicate?
Decreased blood flow through the organs
What does a high MAP indicate?
Increased cardaic workload
What is the MAP needed to adequately perfuse and sustain vital organs of an average person?
60 mm Hg
roughly equal to a systolic blood pressure of 90 mm Hg
What is starling's law?
The greater the stretch of the ventricular muscle fiber, the greater the contraction, to a point.
What is preload?
Preload occurs during diastole. The term refers to the volume of blood filling the ventricles prior to the beginning of systole. Preload is regulated by the variability in intravascular volume and the volume of blood returning to the ventricle.
WRONG. THIS IS WRONG
What is afterload?
Afterload describes the resistance that the heart has to overcome, during every beat, to send blood forward into the aorta. These resistive forces include vasoactivity (blood vessel diameter and rigidity) and blood viscosity
WRONGGGGGGGGGg. This is WRONG. THESE TEACHERS ARE SO STUPID
What is contractility?
Describes the strength of cardiac muscle contraction
What is cardiac output?
The volume of blood pumped by the heart in one minute
HR X SV = CO
What is stroke volume (SV)?
The amount of blood pumped by the heart per cardiac cycle. It is measured in mL/beat.
What are positive Inotropes?
Any medication or circumstances that increases the force of cardiac contraction
What are negative Inotropes
Any medication or cicumstances that decrease the force of cardiac contraction
What is hemodynamic monitoring?
The measurment of pressure, flow, and oxygenation within the cardiovascular system. Values commonly obtained VIA an invasive catheter include central venous pressure, pulmonary artery pressure, pulmonary atery wedge pressure, cardiac output, and stroke volume.
What is pulmonary vascular resistance (PVR)?
The measure of resistance of the pulmonary vascular bed to blood flow
What is systemic vascular resistance?
The measurement of resistance of the systemic vascular bed to blood flow
What is left ventricular ejection fraction?
Also referred to as ejection fraction. This is the percent of blood ejected from the left ventricle during one cardiac cycle. The average EF is 55-65%.
What is central venous pressure (CVP)?
CVP readings are used to assess right ventricular function and general fluid status using an invasive hemodynamic catheter
What is pulmonary artery pressure (PA pressure)?
Blood pressure in the pulmonary artery measured by invasive hemodynamic catheter.
What is pulmonary wedge pressure (PAWP)?
PAWP pressures are used to assess the preload of the left ventricle. This is measured through the invasive hemodynamic catheter.
Cardiac Output, Decreased
Definition: Inadequate volume of blood pumped by the heart/minute to meet metabolic demands of the body
- Altered HR/rhythm, EKG changes
- Altered preload: edema, decreased CVP, fatigue, JVD, heart murmurs, weight gain
- Altered afterload: clammy skin, dyspnea, decreased peripheral pulses, increased PVR, oliguria, prolonged CRT, skin color changes
- Altered contractility: crackles, cough, decreased ejection fraction, orthopena, PND
- Behavioral/Emotional: anxiety, restlessness
- Pt. will demonstrate adequate CO as evidenced by BP, HR and rhythm within normal parameters for patient
- Strong peripheral pulses and an ability to tolerate activity without symptoms of dyspnea, syncope, or chest pain
- S/sx of heart failure and decreased cardiac output
- Lung sounds, weight, dyspnea, orthopnea, PND, c/o fatigue or weakness
- Chest pain/discomfort, note location, radiationm, severity, quality, duration, and associated symptoms such as nausea, indigestion, and diaphoresis, note precipitating and alleviating factors
- I/O with hourly urine output
- Diagnostic imaging studies such as echo with particular attention to ejection fraction. EF less than 40% indicating heart failure
- Lab values, especially ABGs, electrolytes and B-type natriuretic peptide
- Bowel function, provide stool softeners and caution patient not to strain (avoid valsalva)
- Administer O2 per order to maintain satisfactory SpO2
- Check pulse, BP before and after administering ACE- I, digoxin, CCB and beta blockers
What is the catheter called that is used in hemodynamic monitoring?
It is a special central venous catheter called the pulmonary artery catheter.
Where is the pulmonary artery catheter inserted?
Through a central vein and is advanced until the tip of the catheter rests within a small branch of the pulmonary artery
What is the purpose of inserting a pulmonary artery catheter?
The data obtained from the catheter provides measurable/numeric information about the overall functioning of the heart. This data enables the RN to continually assess the patient's response to actual or potential cardiac problems and adject the associated nursing care appropriately.
What does the stupid student think preload is?
Preload is the volume of blood in the ventricle prior to contraction. Preload is related to the length and stretch of the myocardial fibers at the end of diastole. If you recall starling's law, the more a heart fiber is stretched during diastole, the greater the contraction of the muscle will be. This stretch is accomplished through filling of the ventricle with the blood. This is significant because the heart is a dynamic pump which must alter its output with the amount of blood it recieves. It is a necessary property of cardiac muscle that the force develope dudring systole is matche dto the volume of blood received during diastole. Proload then, is directly related to volume of vlood that the ventricle receives during diastole.
Preload is mainly dependent on the return of venous blood from the body for the right ventricle and from the pulmonary system for the left ventricle. Venous return is influenced by changes in position, intra-thoracic pressure, blood volume, and the balance of constriction and dilation (tone) in the venous system. As preload is increased, the heart responds with a stronger contraction. This is seen with increase in both the stroke volume and cardiac output values. Increase in preload and the heart response require increase in both the energy and oxygen consumption of the heart's tissue (myocardial oxygen demand).
Preload in the right ventricle is measured directly by the central venous pressure using an invasive catheter. Left ventricular preload can be measured indirectly through the use of a pulmonary artery catheter. The pulmonary wedge pressure is a reflection of left atrial pressure.
**some of this is correct, but mostly they are confused.
What are the preload parameters?
Central Venous Pressure (CVP): Reflects fluid volume on the venous side of the vascular system
Pulmonary Artery Wedge Pressure (PAWP): Fluid volume on the arterial side of the vascular system
What are the factors that increase preload?
- Increase in fluid intake
- Use of anti-emobolic stockings
- Trendelenburg position or elevation of legs
What are the factors that decrease preload?
- Use of diuretics
- Decrease in fluid intake
- Use of vasodilators (such as nitrates and morphine)
What data should be included in the assessment of preload status in patients with cardiac issues at the bedside without invasive hemodynamic monitoring?
- Daily weight
- Monitor 24 hour I&O, including IV fluids
- Monitor edema
- Assess for JVD, heart gallop (S3 or S4), and crackles
- Assess skin turgor and moisture of mucuous membranes
- Assess BP and pulse
- Assess for thirst
- Invasive pressure monitoring (R atrial pressure or central venous pressure)
- Medication history (diuretics)
If a patient demonstrated an increased in their CVP parameter, what would this represent as to preload?
Increase in CVP means increase in preload
What do your stupid teachers think preload is?
Afterload is the resistance which the ventricles must pump blood out against. Afterload is determined by two conditions: blood pressure and the diameter of the blood vessels. If blood pressure increases or vessels are constricted, afterload is increased. The resistance of systemic BP to the left ventricle is the systemic vascular resistance (SVR). The resistance of pulmonary BP to the right ventricle is the pulmonary vascular resistance (PVR).
What are the afterload parameters?
Pulmonary Vascular Resistance: reflects pressure in the pulmonary vascular bed
Systemic Vascular Resistance: reflects pressure in the systemic arterial system (think vasomotor tone)
What are some factors that increase afterload?
- Left sided heart failure
- Pulmonary diseases (COPD, etc)
- Pulmonary or Systemic hypertension
- Valvular stenosis (valves fail, blood leaks backward)
- Vasoconstriction (from intrinsic factors such as hypothermia, or extrinsic factors such as medications)
What are some factors that decrease afterload?
- Vasodilation (from intrinsic factors such as sepsis/shock or extrinsic factors such as medications)
- Hyperthermia (hot, dilation)
What data should be included in the assessment of the afterload status in patients with cardiac problems at the bedside without invasive monitoring?
- Hx of valvular stenosis
- Hx of pulmonary diseases
- Medications that can cause changes in vasomotor tone or myocardial contractility
What do your stupid teachers think about contracility?
Contractility refers to the force of myocardial muscle contraction. Factors that positively affect contractility, thus increase the force of muscle contraction, are called positive inotropes. Factors that negatively affect or diminish the force of contraction of the myocardium are called negative inotropes. An increased contractility will result in an increase in stroke volume.
What are some positive inotropes?
Medications such as:
Sympathetic nervous system stimulation
What are some negative inotropes?
Medications such as:
- Beta blockers
- Calcium channel blockers
Parasympathetic nervous system stimulation (rest and digest)
What do your stupid teachers think about cardiac output?
Cardiac output is the volume of blood that is ejected from the heart per minute. For the body to function properly, the heart needs to pump blood at a sufficient rate to maintain an adequate and contiuous supply of oxygen and other nutrients to all organs. Cardiac output is dependent on both the HR and the stroke volume (SV). Factors that affect the CO include any alterations in either HR and/or SV. Stroke volume is affected by preload, afterload, and contractility.
What is the normal CO range for an adult?
4-8 L /minute
What happens when the patient experiences a low CO?
The heart tries to compensate by alterations in either HR or SV
In the absence of hemodynamic monitoring, what non-invasive assessment data give the RN an indication of cardiac output?
- skin temp
- HR and quality
- Lung sounds
What strategies can the RN incorporate to minimize valsalva?
- Increase fluid intake
- Stool softeners
- Increase diber
- Avoid holding breath with acitivity
What activities can result in the valsalva meneuver and what is the effect on hemodynamic function?
- When pt. takes a deep breath, holds it, traps air it increases intra-abdominal and intrathoracic pressure an ddecreases blood volume to the right atrium (reduces preload and CO)
- Holding breath can also stimulate vagus nerve with temporary bradycardia, also decreased CO
- When intra-thoracic pressure is released, increase in HR as heart accommodates change in volume and pressure
- Patient with poor heart function may not tolerate and prone to fatal dysrhythmia
- Elderly patients with heart failure, cerebral edema, HTN, CAD, recent MI increases risk
What would you expect in a patient with a low ejection fraction?
Severe activity intolerance. Patient's enegy is being used for basic needs (breathing, heart beating, circulation, digesting). Expectations for total self-care unrealisitic - exhausted with minimal exertion. Assess for signs of worsening CO and assist patient to meet needs.';lk
What other nursing diagnoses may apply in a patient with decreased cardiac output?
- Activity Intolerance
- Ineffective Tissue Perfusion
How is an apical-radial pulse determined?
May be used to determine whether each heartbeat perfuses blood to the periphery.
2 nurses, 1 watch. 1st nurse listens to the apical pulse and 2nd nurse palpates the radial pulse during the same minute.
Normal: should be the same number of beats
Abnormal: apical pulse is higher than the radial pulse
Other, less specific way:
1 nurse to auscultate apical and palpate radial at same time, heart beat should be followed by a pulsation at radial site
What is the significance of a apical-radial pulse deficit?
A pulse deficit indicates diminished peripheral perfusion that could be aused vby decreased cardiac output. A pulse deficit greater than 5 could be significant