Basic hemodynamics for review.

1. Hemodynamic
monitoring
Monica Espinal

2. Objectives
Learner will be able to state the definition
of basic hemodynamic terms.
• The definition of hemodynamics.
• The factors determining hemodynamics.
• The definition of cardiac output.
• Factors that determine cardiac output.
• The definitions for preload, afterload,
contractility.
• Define cardiogenic shock, septic shock,
hypovolemic shock and treatments.

3. WHAT IS
HEMODYNAMIC MONITORING
Simply stated hemodynamics is about pressure.
Involves movement of blood.
The measurement and monitoring factors that influence
the force and flow of blood.
Universal law, all matter seeks its lowest possible energy
state
For blood it means trying to be at lowest pressure
gradient. Hence going from highest to lowest pressure.

4. Gases also obey this
pressure gradient
• The reason carbon
dioxide jumps off the
blood stream,
through alveolar
capillary membrane
and into alveoli is
because there is less
CO2 there.

5. Circulatory System
Circulatory system divided into two major parts:
Pulmonary System Systemic System
Pulmonary system made up of the
right side of the heart right (right Systemic is made up of left side of
atrium & right ventricle), the heart (left atrium and left
pulmonary arteries, & pulmonary ventricle), the arteries and veins.
veins.
Carry oxygenated blood from the
Arteries direct blood from the right
left heart to different organ
ventricle to the lungs. Veins
systems. Veins partially return the
conduct oxygenated blood from
deoxygenated blood back to right
lungs to left side of the heart.
side of the heart.

6. Simple Circulatory System
Diagrams

7. IN THE
CIRCULATORY SYSTEM
Heart is the pump that provides power
to move blood throughout the blood
vessels (perfusion)
Blood vessels direct blood from the
heart to tissues through arteries and
capillaries (circulatory system) and
back to the right heart through the
veins
Blood is the medium in which oxygen
and other nutrients are carried to the
tissues.

8. Blood moves
downstream
• When leaving left
ventricle pressure is
about 120/80 mmgh
• In capillaries pressure is
about 20 mmHg
• From capillaries , back to the
right heart where pressure is
about 4mmHg

9. WHAT IS CARDIAC OUTPUT
Cardiac output is the quantity of blood pumped out by the
left ventricle in each minute. Normal 4 - 8 L/min*
Cardiac output is the product of heart rate and stroke
volume (the vol. of blood ejected by the ventricle w/ each
contraction.)
Stroke volume is the volume of blood ejected by the
ventricles by a single heart beat. Normal 60 -120ml/beat
Cardiac output divided by body surface area is known
as Cardiac Index. Normal 2.5 - to 4.0 L/min/m2*

10. What determines cardiac output?
Heart Rate and Stroke Volume!!
Stroke volume is a function of three important factors.
Stroke volume is the volume of blood ejected by the ventricle by a single heart beat.
Normal for adults 60 to 130 ml/beat.

11. Stroke volume is a function of three important factors.
Preload After-load Contractility
Arterial resistance to flow
Filling volume of the Forcefulness of myocardial
out of the ventricles during
ventricles (diastole). contraction
contraction (aortic bp)
SVR indicates afterload for If the ventricle is adequately
the L. ventricle. PVR indicates filled & resistance to outflow
The filling volume of the afterload for the R. ventricle. optimal, cardiac output will
ventricles prior to not be adequate if contractility
Appropriate level of afterload
contraction is one to the is poor. Factors that reduce
for the L. ventricle is essential
most important factors cardiac contractility are called
to maintain adequate
determining the negative inotropes & include
perfusion pressure to the
subsequent volume of hypoxemia, acidosis, &
body. in afterload
blood ejected during medications such as beta
(peripheral vasodilation) will
systole. Too little filling blockers.
cause BP to drop. in BP will
or too much filling leads Factors that increase
stimulate the heart to C.O.
to a reduced stroke contractility are called positive
to maintain circulation.
volume. inotropes and include certain
The interaction between C.O. beta-adrenergics and
& after-load determines BP. parasympatholytics.

12. Five factors we look at to
determine hemodynamics
• Right heart
• Lungs
• Left Heart
• Too much fluid
• Not enough fluid

13. Hemodynamics is all
about pressures
• CVP: Central Venous Pressure (before the R. heart)
• PAP: Pulmonary Artery Pressure (after the R. heart)
• PCWP: Pulmonary Wedge Pressure (after the lungs)
• C.O Cardiac Output: although not a pressure but a
volume it also relates to pressure (after the L. heart)
• We are concerned about the functions that lies
between these pressure values (i.e. right heart, lungs,
left heart, and the systemic vascular system.)

14. Normal
Values
Also called right atrial pressure, right side
preload, right ventricular end diastolic
Measurement taken at the
pressure... they all use right as description
R. atrium or vena cava.
CVP 2-6 mmHg
Looks at function of right Low values may be High values
heart in general dehydration or relates to fluid
vasodilation - fluids or overload -
vasoconstriction drugs. diurese the pt.
Measurement taken w/
6 - 15
transducer at tip of
PAP mmHg
catheter placed in
Also called Right ventricular after- load.
(mean 14) pulmonary artery.
Measurement taken w/ Also called left atrial
6-12 Relates to
balloon-tipped catheter pressure, left ventricular
PCWP Normal 8 inflated and wedge in filling pressure, left
function of Left
mmHg heart.
pulmonary artery. ventricular preload
If CO is , usu.
Expressed as volume Generally relates to Left treat w/ cardiac
C.O 4 - 8 L/min
ventricle inotropics or
rather than pressure.
chronotropics.

15. Pressure after Relates to function
the right heart of left heart
PAP = 6 - 15 PCWP = 6 - 12
C.O. = 4 - 8
CVP = 2 - 6 Pulmonary L/min
Pressure vascular
before the system Generally
right heart relates to
condition of
left ventricle
Right heart Left Heart

16. QUICK QUESTIONS TO ASK YOURSELF
WHEN LOOKING AT THESE PRESSURES.
What two pressure would you look
at for right heart function?
CVP and PAP CVP Before R. heart
PAP After R. heart
What two pressures would look at PWCP After lungs
for blood flow to the lungs? C.O. After L. heart
PAP and PCWP
What about left heart?
PCWP and then volume C.O.

17. Etiology
Results form inadequate cardiac contractility. Most common in
the United states and most often seen in patients experiencing a
Cardiogenic shock: myocardial infarction. Approximately 6 to 7% of patients
having an M.I. develop cardiogenic shock.
Failure of vascular tone most often seen in the septic patient.
Septic shock causes complex problems with maldistribution of
flow resulting in severe vasodilation and a very low afterload.
Distributive shock: Cardiac output is often increased, but flow to vital organs is
often inadequate owing to low perfusion pressures and
persistent hypotension.
Hypovolemic Inadequate or decrease circulating blood volume. Can be a
shock: result of bleeding from trauma, surgery, or dehydration.

18. Treatment
Positive inotropes and vasopressors are the primary approach.
Inotropics, chronotropes, and vasocontrictors, such as
dopamines and norepinephrine, may be needed to improve
Cardiogenic shock:
blood pressure. Inotropics should NOT be used if patient is
suspected of having acute myocardial infarction given that in
can further stress the heart and extend infarctions.
Antibiotics and volume expansion are essential for patients in
septic shock. Volume expansion improves BP by filling the void
created by the peripheral vasodilation associated with sepsis.
Distributive shock: Vasopressors such as dopamine and norepinephrine improve
hypotension by partially reversing the vasodilation caused by
sepsis and by stimulating contractility therefore improving
cardiac output..
Rapid replacement of circulating blood volume is crucial. As a
rule, fluid resuscitation is needed whenever the systolic blood
pressure is below 90mm Hg and there are no signs of vital
Hypovolemic
organ disfunction (abnormal sensorium). If patient had large
shock: amount of blood loss, it is ideal to use blood as a replacement.
If hypovolemic shock is not caused by bleeding, saline
solutions are effective in aiding circulating blood.

19. Treatment Conclusion
• Oxygen!!
• Mechanical ventilation is most often needed in the
patient with the type of shock that does not resolve
quickly. Those with septic shock or sever
cardiogenic shock most often need mechanical
ventilation given that it aids in reducing oxygen
consumption of the respiratory muscles.
• Close monitoring of all patients diagnosed with
shock in the ICU is important.

20. Thank you for
listening.