Block 1 Unit 2 Adult And Pediatric Hemodynamic Values Flashcards
What’s the definition of Hemodynamics?
The physical and physiological principles of governing the movement of blood through the circulatory system
The principles of hemodynamics are divided into 3 categories, what are they?
- Preload
- Contractility
- Afterload
What is Preload?
The volume of venous blood being returned to the heart.
What happened to the heart during Preload?
Preload is essentially the stretch of the right ventricle by the volume of the blood filling the chamber.
Think of it as the tank filling up with blood.
What is Contractility? ( HEMO)
The force of the myocardium during systolic ejection
What is Afterload?
The resistance to the systolic ejection.
The load or pressure that the heart must eject against.
The obstacle that the ventricle must overcome in order to eject the contents
What is the physiology effects of decreased Preload?
Decreased venous return and or decreased blood volume.
What Factors/ conditions may decrease a pts preload?
- Hypovolemia due to hemorrhage
- Vasodilation from sepsis
- Trauma
- Shock
- Impaired atrial contractions e.g A-Fib
What is the physiology effects of increased Preload?
- increased venous return aka fast filling time
Think of the tank being over filled
What Factors/ conditions may increase a pts preload?
- Volume Overload
- Vasoconstriction
- R Heart Disease
- Increased Intrathoracic Pressures
- Intrathoracic Mass
- Pneumothorax
- Positive Pressure Ventilation
What is the physiology effects of decreased Contractility?
Stimulation of the parasympathetic nervous system, releasing the hormone acetylcholine, which decreases HR and BP
What Factors/ conditions may decrease a pts contractility?
- Vagal Maneuvers
- Drugs
- Hypothermia
- Hypoxia
- Ischemia
- Hyperkalemia
- Positive Pressure Ventilation
What is the physiology effects of increased Contractility?
Sympathetic nervous system stimulation increases HR/BP
What Factors/ conditions may increase a pts contractility?
- Exercise
- Emotional Excitement
- Medications such as Epinephrine and Norepinephrine
- HF
What is the physiology effects of decreased afterload?
Decrease in vascular resistance; the resistance in the circulatory system that is used to create BP and control the flow of blood (decreased BP)
What Factors/ conditions may decrease a pts Afterload?
- Hypotension
- Hypovolemia
- Shock
- Vasodilators
What is the physiology effect of increased afterload?
-The heart has to work harder to open the valves and eject blood
- increased BP
What Factors/ conditions may increase a pts Afterload?
- Hypertension
- Aortic Stenosis
- Cardiovascular Disease
- Ventricular Hypertrophy
- CHF
What is Hemodynamic monitoring?
The measurement and interpretation of the performance of the cardiovascular system. It evaluates cardiac performance and oxygenation.
Why do we monitor hemodynamics?
- Early detection
- Identification of the cause
- Tx of physiologic change
- evaluate cardiovascular function
- Assess response to therapeutic interventions
How does hemodynamic monitoring, determine cardiac performance and tissue perfusion?
- Cardiac output
- BP
- Intra-Cardiac volume/ Pressures
- saturation of venous oxygenation ( Mixed Venous)
What is MAP?
Mean Arterial Pressure, Average of BP
What is our MAP important and what is our goal?
It’s is a great indicator of perfusion; MAP greater than 60 will keep all organs perfused.
What is Systolic blood pressure?
Blood Is ejected into the arteries, during a heartbeat
What is Diastolic blood pressure?
Pressure is exerted within the arteries, between heartbeat
How are non-invasive O2 saturation calculated?
Using a skin probe
How are invasive O2 saturation calculated?
With arterial blood from an ABG
What is Cardiac Index?
Amount of cardiac output corrected for body surface area
How is the Cardiac Index calculated?
Cardiac Output / BSA.
Cardiac output increases or decreases in proportion to the surface area of the body
What is Central Venous Pressure?
The pressure in the Vena Cava/ R atrial pressure
How is CVP measured?
Using the distal port of a central line.
What is Ejection Fraction?
The fraction of the end diastolic ventricular volume that is ejected.
It’s a percentage that expressed how much blood the L ventricle pump south w/ each contraction and how well the heart is pumping blood to the body.
You have a pt who has a EF of < 40%, what is this evidence of?
Heart Failure.
With early detection and proper care/treatment, a pt can improve their EF.
T or F?
True
What does Systemic Vascular Resistance represents?
A quantitative value for the left ventricle afterload.
It reflects changes in the arterioles which can effect the emptying of the left ventricle
What does SVR help with?
Helps to differentiate among ideologies and guide therapy.
What is pulmonary artery pressure?
Measure the resistance in the pulmonary vasculature.
PAP assists in the dx of what?
Pulmonary HTN
What is a pulmonary artery wedge/occlusive pressure?
A value that is measured by wedging, or occluding a pulmonary catheter with an inflated balloon in the branch of a pulmonary artery
PAWP/ PAOP helps in the dx’ing the severity of what?
L Ventricular Failure
What provides the most accurate and continuous blood pressure value?
Arterial Blood Pressure
What’s an adult normal HR?
60-100 bpm
What is considered bradycardia within an adult?
< 60 bpm
What is considered tachycardia within an adult?
> 100 bpm
How do you calculate your MAP value?
SBP+( DBPx2)/3
What is a Stroke volume?
Amount of blood ejected from each ventricle with each heartbeat
What port is used to measure a CVP?
Central line, distal port
When are you supposed to zero your A-line?
At the beginning of your shift and with each assessment and/or position change
Why do we perform a square waveform test?
Performed to ensure waveform/ pressure are accurate
What is a normal waveform test result?
Square waveform shows a square pattern with one or two oscillations before the return of the arterial waveform
The dicrotic notch demarcates what?
The end of systole and beginning of diastole.
When performing a square waveform test with a fast flush, you see there are several oscillations after the square waveform. What does this indicate?
An underdamped arterial line
What will happen if you have a underdamped arterial line?
False high SBP and false low DBP
What causes a underdamped A-Line?
Extra long tubing, excessive stopcocks, and patients condition.
After the flash flush, you receive one/ no oscillations that proceed and your upstroke of the waveform is slurred with loss of height and no visible dicrotic notch. What does this entail?
Overdamped arterial line
What is the result of a overdamped A-Line?
False low SBP and false high DBP
What causes a overdamped A-line?
- Obstruction in line
- Air blood or blood clots
- Kinked lines
You have a CVP < 4, what does this indicate?
Hypovolemia or venodilation
You have a CVP > 8, what does this indicate?
R HF, Cardiac ischemia, or fluid overload
What additional information does CVP provide?
- R ventricle preload
- Cardiovascular status
- fluid balance
