Exam 2: 11 Feb 25 Regulation of CO and BP During Stress Flashcards
What is Cardiac Output?
The volume of blood the heart pumps per minute, crucial for maintaining blood flow to organs.
Define Blood Pressure.
The force exerted by circulating blood on the walls of blood vessels, essential for organ perfusion.
What are Baroreceptors?
Sensors located in the carotid sinus and aortic arch that detect changes in blood pressure and help regulate it.
What role does Vasopressin play in the body?
A hormone that helps regulate blood pressure by promoting water retention and vasoconstriction.
What is Atrial Natriuretic Peptide (ANP)?
A hormone released by the heart that reduces blood volume and pressure by promoting sodium excretion.
What does the Renin-Angiotensin-Aldosterone System (RAAS) do?
A hormone system that regulates blood pressure and fluid balance, crucial during stress and hemorrhage.
What is the CNS Ischemic Response?
The body’s strongest sympathetic nervous system response to low blood pressure, aimed at restoring perfusion to critical organs.
What is the Fick Equation used for?
A method for estimating cardiac output based on oxygen content measurements in blood.
What is the formula for Cardiac Output?
Cardiac Output (CO) = Stroke Volume (SV) x Heart Rate (HR).
What are the normal values for Cardiac Output?
CO ~ 5-6 L/min, Blood Volume ~ 5 L.
Fill in the blank: Atrial Natriuretic Peptide (ANP) and B-type Natriuretic Peptide (BNP) are released in response to _______.
atrial stretch.
True or False: Normal saline can cause pulmonary issues if overused in volume replacement.
True.
Where are Baroreceptors located?
In the carotid sinus and aortic arch.
What is the primary neurotransmitter for sympathetic nervous system responses?
Norepinephrine.
What is Cardiac Reserve?
The maximum increase in cardiac output above normal levels.
How does Atrial Natriuretic Peptide (ANP) function?
Reduces blood volume by increasing urine output and sodium excretion.
What condition is B-type Natriuretic Peptide (BNP) used to assess?
Heart failure.
What do Cardiac Glycosides like Digoxin do?
Increase contractility of the heart by inhibiting sodium-potassium ATPase.
What is the goal of drug therapy in heart failure?
To augment the body’s compensatory mechanisms and buy time for heart recovery.
What happens to the kidneys in response to increased atrial stretch?
Increased urine output, reducing blood volume.
Fill in the blank: The _______ axis is crucial for blood pressure regulation.
renin-angiotensin-aldosterone.
What are the clinical implications of ANP and BNP in heart failure management?
They can be used to monitor treatment effectiveness.
What happens to blood volume and plasma proteins during hemorrhage?
Blood volume decreases, and fluid is redistributed to maintain plasma volume.
What is the importance of fluid replacement during blood loss?
To restore blood volume and maintain circulation.
True or False: BNP has long-lasting effects in the body.
False.
What is the normal blood volume in the body?
About 5 liters.
What fluid dynamics occur if 20% of blood volume is lost?
Serious but not immediately fatal; fluid redistributes between compartments.
What percentage of blood volume loss can be serious but not immediately fatal?
20%
How much plasma and red blood cells are lost when losing 1 liter of blood?
- 600 cc’s of plasma
- 400 cc’s of red blood cells
What happens to fluid distribution after blood loss?
Fluid redistributes between compartments
What is the role of plasma proteins in the cardiovascular system?
They help maintain oncotic pressure
What is oncotic pressure?
The pressure that keeps fluid in the cardiovascular system
What happens if plasma proteins are lost?
Oncotic pressure decreases
What is the best way to replace lost fluids after bleeding?
Replace what’s missing, such as plasma
What is a limitation of normal saline as a fluid replacement?
It lacks colloids, leading to fluid loss to interstitial space
What could excessive normal saline administration lead to?
Pulmonary edema
What are synthetic colloids used for?
To produce oncotic pressure and remain in the cardiovascular system
What physiological response occurs if fluid is administered quickly?
Increase in cardiac output and blood pressure
What is stretch relaxation?
A response of smooth muscle that reduces venous pressure over time
What triggers the CNS ischemic response?
Low brain or brain stem perfusion
What are the consequences of shock on the body?
- Tissue dysfunction
- Cell necrosis
- Hyperkalemia
Which organs are particularly sensitive to ischemia during shock?
- Brain
- Heart
- Kidneys
- Liver
What methods can estimate cardiac output?
- PA catheter
- Thermal dilution
- Software and blood pressure tracing
What is the normal oxygen consumption for a healthy adult?
250 mls of O2 per minute
What is the thick equation for calculating cardiac output?
Depends on oxygen levels and delivery needs
What is digoxin primarily used for?
To inhibit the sodium-potassium ATPase pump
What is aortic stenosis?
The most common heart valve problem
What happens if the aortic valve does not close completely?
Blood is funneled back into the ventricle
What is the significance of ANP and BNP in heart failure?
They promote diuresis and indicate cardiac function
How does anesthesia affect blood pressure and cardiac output?
It can impair compensatory mechanisms
What does cardiac reserve refer to?
The maximum increase in cardiac output above resting levels
What are the main arteries involved in typical coronary circulation?
LCA, RCA, Circumflex Artery, PDA, LAD
LCA: Left Coronary Artery, RCA: Right Coronary Artery, PDA: Posterior Descending Artery, LAD: Left Anterior Descending.
List the types of heart valve abnormalities.
- Aortic Stenosis
- Aortic Insufficiency
- Mitral Stenosis
- Mitral Insufficiency
These conditions affect normal heart valve function.
What does reduced ventricular compliance indicate?
Higher CVP requirement, altered stroke volume, changes in ventricular wall behavior
CVP: Central Venous Pressure.
What is the normal cardiac output in a healthy adult?
~5 L/min
This value can vary based on individual health and physical condition.
Fill in the blank: Fetal circulation includes the _______.
Patent Ductus Arteriosus
This structure connects the pulmonary artery to the aorta in fetal circulation.
What are the signs of acute heart failure?
- Increased right atrial pressures
- Central venous pressure likely to increase
- Progressive worsening of cardiac output
These signs indicate severe heart dysfunction.
What is the Fick Equation and what is it used for?
To measure cardiac output based on oxygen delivery and blood flow requirements
* CO=VO2/(CaO2-CvO2)
i.e. 5L/min=250ml/min/(20mL/dL-15mL/dL)
It is a method to assess the efficiency of the cardiovascular system.
True or False: A normal cycle of pulse pressure variation (PPV) is affected by ventilation.
True
PPV can indicate fluid responsiveness and is influenced by respiratory patterns.
