Cardiac output calculator
Each ventricle
that pumps the blood into the body that called cardiac output. That refers to
liters per minute. It's flowing in the systemic & pulmonary cycle.
Those
formula calculated cardiac output that called cardiac output calculator.
So, this
formula is,
Cardiac
output = no. of heart rate / stroke volume.
CO = HR * SV
Heart rate means
a no. of beats per minute.
Stroke volume
means a blood volume is ejected by each ventricle with their every beat.
Understand cardiac
output calculator for very easy ways like,
If ventricle
heartbeat is 72 per minute & stroke volume (ejected blood through
ventricles) are 60 ml, so calculate this way,
CARDIAC OUTPUT =
72 beats per min * 0.06 liter per beat = 4.32 liter per minute
The average blood
volume in one minute is around 5.5 liter (resting condition). Also, a depends
on the exercise it may be various. During the extreme exercise & some
athletes, cardiac output is around a 35 liter per minute. Because heartbeats
& stroke volume increases during the exercise.
Also, during
exercise normal man cardiac output in exercise is 20-25 liter per minute.
Just two factors affect the cardiac output,
➠ Heart rate
➠ Stroke volume
Please, keep in
mind heart rate & stroke volume does not change in the same direction. For example,
if any blood loss condition stroke volume decreases but heart rate increases. So, it can produce the opposite result.
➣ Heart rate
The average heart
rate in human is almost 72 to 75 beats
per minute. That is not any hormonal & nervous influence. But any other
condition this heart rate may be decreased or increase it depends on hormonal
& nervous system.
The sympathetic
neurons that cause heart rate increase, whereas, parasympathetic neurons that
cause heart rate decrease. That called a chronotropic effect.
It’s also a
innervate other parts of the conducting system. Sympathetic is increase the
conduction velocity through the cardiac conducting system and parasympathetic
decrease the speed of excitation through AV & atria node. That’s called a dromotropic effect.
The normal
resting-state more parasympathetic activity produce than sympathetic activity.
So, that’s why the normal heart rate is 72 to 75 beats per minute. It’s well below
the inherent rate of 100 beats per minute.
Sympathetic & parasympathetic are
influence the SA node potential. Sympathetic are stimulate the pacemaker potential
by the F – type of channel permeability. That the sodium current that enters in
the cell. Cells are depolarized. That causes SA nodes are reached that threshold
potential & increase the heart rate.
Parasympathetic
are opposite to the sympathetic. It stimulates the hyperpolarize (negative ion increases
in the cell) to the plasma membrane reduce the current & decrease the heart
rate.
The plasma
epinephrine is increasing the heart rate & norepinephrine are decrease the
heart rate.
Cardiac nerve can
also alter the heart rate. Epinephrine & norepinephrine are also affecting
the heart rate. Other many factors that affect the heart rate like, body temperature,
other hormonal changes, plasma electrolyte concentration or etc.
➣ Stroke volume
In cardiac output
calculator stroke volume the second important variable. The volume of blood ejects
during each cardiac breath that called a stroke volume. That is not completely
empty during the concentration.
So, forcefully
contraction is increasing the stroke volume & slow contraction are decreases
the heart rate. So, various contraction is affecting the stoke volume.
Three major
factors that affect stroke volume.
The frank- starling mechanism (end
diastolic movement)
Sympathetic nervous system
Afterload.
⇨ The frank – starling mechanism
In systole
condition the ventricle are more forcefully contracts, in other words, stroke volume can be increased when end-diastolic volume increases.
This relationship
called a frank – starling mechanism. Also, a called a staring law of the heart .
The greater the
end-diastolic, the more stretch the skeletal muscle & more forcefully
contraction are producing.
When the heart
rate increases the flow of blood from veins to the heart also increases.
Automaticity
of force increase in cardiac output by increasing its end-diastolic
volume. And also, an increase in the stroke
volume.
 |
| cardiac output calculator |
CARDIAC OUTPUT → STROKE VOLUME * HEART
RATE
When stroke volume & heart rate increase in the above condition, definitely, the cardiac output is increase.
⇨ Sympathetic regulation
The sympathetic
neurotransmitter of norepinephrine acts on the β adrenergic
receptor to increase its ventricular contractility. Which is a process to
generate to force of contraction. Epinephrine are acts on these receptors to
also increase myocardial contractility.
So, that is
increase the force of contraction & stroke volume that result also a
sympathetic nerve stimulation. The frank starling mechanism still applied, during the sympathetic
stimulation, stroke volume is also an increase.
Increase the
contraction, more ejection produces.
Ejection fraction (EF) = stroke volume / end volume diastolic
In heart resting
condition ejection fraction average is 50% & 75%. When increasing the
contractility cause an increase in the ejection fraction.
Not only cause
powerful contraction but also a contraction & relaxation of ventricles occur.
As they increase the sympathetic activity of the heart also increases the heart
rate.
Heart rate increase, the diastolic filling time decrease. The parasympathetic the system has normally negligible, that directly affect the ventricular
contractility.
⇨ Afterload
When the arterial
pressure is increase tends to reduce the stroke volume. Because of the skeletal
muscle lifting a weight, arterial pressure constitutes ‘LOAD’ that contraction
of ventricular muscle.
The term
afterload means how hard to heart must eject the blood.
When the load
greater, less contracting muscle fibers.
In a normal heart,
several inherent adjustments minimize its atrial pressure on the stroke
volume.
Cardiac output measurement
In cardiac output
calculator, cardiac output is measured by many techniques. Like, echocardiography.
It obtains two- or three-dimensional images of the heart by the cardiac cycle. The ultrasonic
waves that beamed on the heart & electrically images plot by computer.
Echocardiograph is
detecting the abnormal functioning of contraction & relaxation of the cardiac wall
as well as detect the abnormal function of the valve. Also, a detect the ejection
fraction.
The other technique
is used cardiac angiography, in cardiac angiography that requires a temporary
threading of thin, the flexible tube called as a catheter by artery or vein in
the heart.
The radiopaque contrast material is injected through a catheter during
the high-speed X-ray videography. Cardiac angiography is useful in cardiac
function as well as identify the narrow coronary arteries.
CONCLUSION :
In this article, you find all details in deep about the cardiac output calculator. like heart rate, stroke volume, etc. I hope you will be like that. if you like to comment out.
