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Cardiac A&P- Cardiac Output & Hemodynamics
Terms in this set (96)
What is normal CO?
5 L/per min
What is normal CO range?
4-8 L/per min at rest
Signs of Parasympathetic
Reduces Electrical Impulses (calms things down)
Decreases Heart Rate
Signs of Sympathetic
Increases Electrical Impulses
Increases Heart Rate
Things that decrease heart rate
Parasympathetic, Beta blockers (beta 1), vomiting, bladder distension
Things that increases heart rate
Sympathetic, Nitrates, Caffeine, Pain, Hypoxia, Anxiety
(cardiac contraction Stroke Volume) valves open, allowing ventricular ejection into arteries (pulmonary artery & Aorta)
Valves close preventing back flow of blood into Ventricles
Cardiac Output equation
Stroke volume x Heart rate= Cardiac output
Cardiac Output definition
The amount of blood pumped out of the ventricle in 1 min.
How much is Stroke Volume?
60-130 mL/ per beat
What is normal pH?
Amount of blood returning to the right atria each minute
What is normal Venous return?
The same as CO. As venous return increases, so does CO.
The role of the Venous system
The muscles, the Liver and the Kidneys receive the greatest amount of blood.
True or False: Venous return increases with peripheral vasodilation and decreases with vasoconstriction
How much blood does the Venous system hold?
64% of blood volume at any given time
Cardiac Index (CI)
Cardiac Index measurement allows a standardized interpretation of the cardiac function.
Cardiac index equation
Cardiac Output/2 = Cardiac index
Normal Cardiac Index is?
A measurement of the energy spent ejecting blood from the ventricles against aortic and pulmonary artery pressures. It correlates well with the amount of oxygen needed by the heart.
Normally cardiac work is much ________ for the left ventricle
Ventricular Stroke Work
A measure of Myocardial work per contraction. The product of Stroke Volume times the pressure across the vascular bed
Estimated by measuring end-diastolic pressure (what's left after ventricular contraction)
The fraction of end-diastolic volume ejected with each systole. Normally 65%-70%, drops with cardiac failure
decreased heart rate = increased stroke volume
If ventricular filling goes up then..
Heart rate goes up
Irregular heart beat
Heart rate is primarily determined by..
Central Nervous System (CNS)
Cardiac output is directly related to..
If the heart rate is >160-180 it causes a decrease of...
Cardiac output, Stroke Volume, Ejection Fraction, End-diastolic volume
Sympathetic Nervous System
To enable the heart of a well-trained athlete to produce a cardiac output of up to 35 L/min, stimulation of the heart muscle is needed through the:
Stretch on Ventricle before contraction
filling the ventricle
Compliance (How fast blood comes back)
Common drugs that reduce Preload
Nitroglycerin, Morphine, Diuretics
Common drugs that increase Preload
Fluids, Blood products, Volume expanders(Colloids, crystalloids- like normal saline)
Resistance to ventricular emptying, Peripheral vascular resistance, ventricular wall tension, increases w/ vasoconstriction, increase in the oxygen demand, decreases w/ vasodilation, blood viscosity
An abnormally increased concentration of hemoglobin in the blood, through either reduction of plasma volume or increase in red cell numbers.
Pushing air into the body is?
Breathing air out of the body is?
Strength of ventricular contraction, sympathetic stimulation, Inotropes, hypoxia, hypercapnia, acidosis, coronary flow, heart muscle damage (if coronary is blocked)
Not enough oxygen
increase of CO2
an agent that alters the force or energy of muscular contractions.
Drugs that effect contractility- positive Inotropes
Calcium, Epinephrine, Norepinephrine, Dopamine, Digitalis, Caffeine
Drugs that effect Contractility- negative Inotropes
Beta blockers(Propranolol), Barbiturates, Procainamide, Quindine
Stroke volume is effected by:
Preload, Contractility, Afterload
Stroke Volume Equation
volume ejected by the ventricle with each contraction
Normal Pulse Pressure
A pulse pressure <30 mmHg indicates what?
A low Stroke Volume (LVSV) by the left Ventricle
If the blood pressure increases with fluid therapy, the patient probably has this
the difference between systolic and diastolic
End-diastolic volume (EDV)
the amount of blood left in the ventricles at the end of the filling cycle (diastole)
End-Systolic Volume (ESV)
the amount of blood left in the ventricles at the end of the contraction (systole)
The following can effect Cardiac Output
Body size(BMI), Tissue demand for oxygen, Hematocrit (viscosity)
Increased Preload can cause:
Leaky valves due to stenosis (especially the Mitral), decreased heart rate, increased stroke volume
Decreased Preload can cause:
Hypovolemia(a decreased volume of circulating blood in the body), increased heart rate, decreased stroke volume, increase in intrathoracic pressure
a decreased volume of circulating blood in the body
Factors that effect Venous return, CO, and Preload
Changes in circulating blood volume, changes in distribution of blood volume, atrial contraction, positive pressure ventilation
States that the energy liberated with each cardiac contraction is a function of the length of the muscle fibers in the ventricular wall; as Preload increases, so does end-diastolic pressure, which increases force of the ventricular contraction.
translation of Starling's Law
The more the stretch, the more the squeeze.
Arterial Monitoring: Indications
Frequent blood draws, Hemodynamics instability, continuous blood pressure assessment, Unstable respiratory failure
Arterial Monitoring: Preferred Sites:
Radial or Femoral artery, Ulnar, brachial, or axillary
Arterial Monitoring: Insertion
Mean Arterial Pressure (MAP) range
Mean Arterial Pressure equation
MAP= Systolic + 2(diastolic) divided by 3
what happens is MAP falls below 60 mmHg?
No perfusion to the brain & Kidneys is severely compromised. Organ failure will happen in minutes
Signs of an Increase in Arterial Pressure
Disease/Disorders, increase systolic BP, decrease diastolic BP, increase positive pressure, arteriosclerosis
Signs of an Decrease in Arterial Pressure
Arrhythmias, LVF, shock, cardiac tamponade, mitral stenosis, obstruction LV output
Hemoglobin has a high affinity for O2
Carries 97% of all O2 in the body
Plasma carries a small portion of:
Increased affinity decreased delivery:
Shift to the left: Increased pH, decreased PCO2, decreased temp, Hypothroidism
Decreased affinity enhanced delivery:
Shift to the right: Decreased pH, increased PCO2, increased temp, Anemia, Hyperthyroidism, Chronic Hypoxemia (PaO2 less than 60)
Coronary arteries received ________ of their perfusion during diastole.
In coronary perfusion, diastolic pressure and MAP is less than?
<50 mmHg and a MAP of <60 mmHg
Increase the force of contractions
If a patient is given Dobutamine, a positive inotropic drug, how is contraction of the heart affected?
Adequacy of Perfusion
What is the most important factor in assessment of the ability of the cardiopulmonary system to meet the body's metabolic demands?
Central Venous Pressure
Pressure of blood in the right atrium (RA) or superior vena cava (SVC)
Insertion sites for a Central Venous Catheter (CVP) or CV line
Subclavian, Internal Jugular and Femoral VEINS- most common
Indicators of a Central Venous Catheter
To assess & monitor fluid status of the pt, to assess right Ventricular function, rapid infusion of fluids & medications, blood draw
Central Venous Catheter effects : Increases
increase venous return (hypervolemia), increase Intrathoracic pressures (PPV, pressure in the rt. atrium), RV failure
Central Venous Catheter effects: Decreases
decrease venous return (Hypovolemia), decrease intrathoracic pressures (spontaneous breathing), increase myocardial contractility (the squeeze)
Methods used to measure cardiac output
Thermodilution (warms the heart), Fick method, Echocardiography
To monitor the RA and the RV you would look at?
To monitor the lungs, you would need?
PAP and PCWP
To monitor the LV and the LA you would need?
To monitor the Aorta and the Systemic circulation, you would need?
The filling Pressure for the right heart is the?
Right Atrial Pressure aka Central Venous Pressure (CVP)
Normal CVP is?
The filling Pressure for the left heart is the?
Left Atrial Pressure aka Pulmonary Capillary Wedge Pressure (PCWP)
Normal PCWP is?
A increase in Pulmonary Vascular Resistance (PVR) is caused by:
PE (obstruction), Acute or chronic lung disease(vasoconstriction caused by Hypoxia), Cardiac Tamponade, increased intrathoracic pressure (PPV)
A decrease in Pulmonary Vascular Resistance (PVR) is caused by:
Decreased venous return (bleeding), Hypovolemia (decreased BP), Vasodilation, increased LV contraction
Pulmonary Vascular Resistance (PVR)
PVR= PAP-PCWP x80 divided CO
Systemic Vascular Resistance (SVR)
PVR= PAP-PCWP x80 divided by CO
Decreased venous return
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