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