Hemodynamic Basics Flashcards
What is the meaning of the term “Hemodynamics”?
What two components is taken into account?
The force by which blood circulates through the body
CO and BP
Why is hemodynamics so important?
It helps with making sure the patient is accomplishing perfusion
What is preload?
Amount of blood filling up the heart when it is relaxing at the end of diastole
- filling pressure
What measurement reflects left ventricular preload ?
PCWP or wedge pressure
What measurement goes with right ventricular pressure?
CVP
- central venous pressure
- fluid status measurement, remember?
List examples that can INCREASED preload and explain why
Exercise (slightly)
- your heart is naturally working harder
Hypervolemia
- too much fluid so its filling more
Neuroendocrine excitement
- fight or flight
AV fistula*
- It allows you to bypass arterioles but it will increase the filling in the heart
Name off examples that cause a DECREASE in preload and explain
Hypovolemia
- the heart can’t fill up if you are dry
Narrow/stenotic valves
- stops ventricle from filling adequately
A.Fib
- the quiver makes you lose the ability to fill and pump
How would you explain Afterload?
The amount of pressure the heart has to overcome in order to perfuse the body
Explain reasons for why there would be an INCREASE in Afterload
Increase systemic resistance (Blood pressure)
Aortic Stenosis
- the aorta supplies the body with blood ; if its valves are stenotic, you can’t push blood out which increases resistance
Myocardial Infarction/Cardiomyopathy
Polycythemia
- thicker blood can’t push out as easy to it has to overcome more pressure
Another term for blood pressure?
SVR or systemic resistance
- often referred to as the same thing
note: svr also reflects after load
What are some factors that DECREASE Afterload?
Decreased volume/dry
- you will have less resistance if your blood is “thinner”
Septic shock
- this is a state of vasodilation so vessel’s open up
End stage Cirrhosis
- Kidney issues are common with this. And if you’re kidneys aren’t working, your heart is affected
Vasodilating meds
- bc they widen the vessels to relax
What happens to the fluid in a septic shock person with decreased afterload? What are the signs?
There can be third spacing
- Decreased BP after compensation doesn’t work
- Cap refill
- Edema
Your patient has end state cirrhosis which is causing a decrease in their after load requirements. What might they look like?
Jaundice
Decrease in UO
Anemic
Bilirubin scabs
Wha labs would you look at for a cirrhosis patient?
Lactate ASLT BUN CR wbc
Contractility meaning
Strength of VENTRICLES contracting
Inotropic meaning
Force or energy of the contraction
Chronotropic meaning
Time and rate related; heart rate
Stroke volume meaning
Amount o blood ejected by the ventricles
Cardiac output meaning
What is the normal trend for this?
HR x SV
CO is the same for everyone
Cardiac index meaning
Similar to CO but more specific to the individual patient due to taking surface area into account
- more reliable
- not the same for everyone
Main types of invasive monitoring?
CVP
Art
Pulmonary artery
How can we insure invasive monitoring is accurate?
Equipment needs to be zeroed to outside influences
Referencing or the positioning of transducer needs to be at the Phlebostatic axis (4th IC)
You raise the HOB of the your patient with an invasive monitoring device. What should you do?
Need to reposition the reference point of the transducer so it aligns with phlebostatic axis
What do you need for invasive monitoring?
Correct catheter
Special tubing system - IV fluids of NS - pressure tubing stopcocks -flusher device - transducer
Pressure bag set at 300 mmhg
- flusher delivers it at 3mLs/hr
Do you pump the pressure bag up or do you spike it?
What is the point of the pressure bag?
Spike it first then pump it up
- its a lot of pressure in there
Keeps you from bleeding out
When zeroing the line, what elevation does the HOB need to be at?
60 degrees
What do you do when zeroing a line?
Open to air
Hit zero function on monitor
And confirm
List instances where you would want to zero the line?
Do it on the initial set up & do it again after the insertion
If you see any changes and need clarification
Beginning of shift
What can you check on the monitor for a clue you’re getting an accurate line reading?
Waveform
