Exam 2 Flashcards
What is normal cardiac output
5-6 liters of blood per minute
Efficiency of the cardiovascular system depends on what four things?
- Heart’s ability to pump
- Patency of the blood vessels
- Quality of the blood
- Quantity of the blood
What is happening during the “P” wave?
Impulse travels through the atria
What happens during the QRS complex?
Impulse travels through the ventricles
What happens during the “T” wave
Re-polarization of the ventricles
When does re-polarization of the atria occur?
Somewhere during the QRS complex
What is polarization?
- Where is sodium
- Where is potassium
Ready or resting state
- Na+ is extracellular
- K+ is intracellular
What is depolarization?
- Where is sodium
- Where is potassium
Contraction
- Na moves into the intracellular
- K+ moves into the extracellular
What is repolarization?
- Where is sodium
- Where is potassium
- Na moves back extracellular
- K moves back intracellular
Role of the autonomic nervous system in control of the heart
PSNS slows heart (negative chronotropic, negative inotropic)
SNS compensates heart that is giong to slow (positive chronotropic, positive inotropic, positive dromotropic)
Two types of hormones that affect the heart
- Catechonlamines (Adrenergic responses)
- Thyroid hormone
Two types of catecholamines that affect the heart
Norepinephrine
Epinephrine
How does Thyroid hormone affect the heart rate
Increased thyroid hormone –> increases BMR –> Increases HR
WBCs originate from (3)
- Bone marrow
- Spleen
- Lymph
Role of albumin
Exerts osmotic pressure intravascularly
Role of fibrinogen
Hemostasis in the plasma
Role of globulins
Defense
General composition of blood
55% plasma
45% solid particles
Composition of plasma (9)
90% water
10% albumin, fibrinogen, globulins, nutrients, oxygen, carbon monoxide, antibodies
What solid particles are in the blood?
- Leukocytes
- Erythrocytes
- Thrombocytes
Normal leukocyte level in the blood
5,000 - 10,000
Normal hematocrit levels
- Males
- Females
- Males: 42-50%
- Females: 40-48%
Normal hemoglobin levels:
- Males
- Females
- Males: 13-18
- Females: 12-16
Normal hemoglobin and hematocrit: Females
Hemoglobin: 12-16
Hematocrit: 40-48%
Normal hemoglobin and hematocrit: Males
Hemoglobin: 13-18
Hematocrit: 42-50%
Functions of the blood (5)
- Transports O2 and Nutrients to the cell
- Transports CO2 and waste away
- Leukocytes and antibodies help fight microorganisms
- Promotes hemostasis (platelets)
- Circulates hormones
Hemostasis: Def
Bringing platelets to the site of injury
Normal platelet count (thrombocytes)
100,000 - 400,000
Location of the aortic valve
2nd intercostal space, right sternal boarder
Location of pulmonic valve
2nd intercostal space, left sternal boarder
Location of Tricuspid valve
4th intercostal space, left sternal border
Location of Mitral valve
5th intercostal space, midclavicular line
Stroke volume (def)
The amount of blood ejected from the heart with each contraction
Heart rate (def)
Beats per minute
Cardiac output (equation)
CO = SV x HR
Average SV
~70
Average HR
~80
Average CO
5.6L / minute
When you think preload, think _______.
VOLUME
When you think afterload, think ______.
PRESSURE
How do you lower preload? (4)
- Vasodilators
- Blood loss
- Diuretics
- FVD
How do you raise preload? (4)
- Vasoconstrictors
- Blood donation
- FVE
- Valve regurg
How do you lower afterload? (3)
- Vasodilatators
- Nitroglycerine
- Hypertrophied left ventricle
How do you raise afterload? (4)
- Vasoconstrictors
- HTN
- Epinephrine
- Dopamine
Arterial pressure must counteract ________
Ventricular systole.
Indirect measurements of CO: Appendages (3)
- 2+ pulses
- Skin is warm and dry
- Good capillary refill
Indirect measurements of CO: Vital signs (3)
- BP WNL
- HR WNL
- RR WNL, breath sounds clear
Indirect measurements of CO: CNS
A&Ox3
Direct measures of CO (2)
- Swan-Ganz / R heart catheter
- Cardiac catheterization
Role of a Swan Ganz / R Heart catheter (2)
1) Monitors fluid load (CVP)
2) Thermester Coupler (2nd lumen) - measures CO
Two locations of baroreceptors
- Aortic arch
- Carotid sinus
Role of baroreceptors
Respond to changes in BP
What do the baroreceptors do when BP rises? + 2 results
Stimulate PSNS
- Vasodilitation
- Decreased HR (Neg Inotrope, Neg chronotrope)
What do the baroreceptors do when BP falls? + 2 results
SNS is stimulated
- Increased HR (positive chronotrope)
- Increased contractility (positive inotrope)
Two locations of chemoreceptors
- Aortic arch
- Carotid sinus
Chemoreceptors respond to changes in… (3)
1) Acidosis (pH 45)
2) Hypercapnia
3) Hypoxia
When stimulated, chemoreceptors will increase… (3)
- RR
- HR
- CO
Left ventricle has to over come pressures in the _______
aorta
Right ventricle has to overcome pressures in the ______
pulmonary system
Cor Pulmonale (def)
Right ventricular Failure
Diagnostic cardiac tests (7)
1) Electrocardiogram
2) Echocardiogram
3) Stress Test
4) Radionucleotide imagery
5) Cat scan
6) Positron Emission
7) Chest X-Ray
Holter Monitor
- What is it
- Function
- Type of portable ECG
- Shows us the 24-hour ECG while patient goes about normal activity
What is a trans esophageal echo (TEE)?
-Indications
Patient swallowsa transducer to get an echocardiogram
- For very obese patients
What is the difference between an Echocardiogram and an Electrocardiogram?
An echocardiogram is a moving picture of structures of the heart – looks at mechanics of valves and walls.
An electrocardiogram (ECG) looks at the electrical activity of the heart only.
How much do arteries expand during stress?
4x larger!
Two types of stress test
- Exercise (pt on treadmill)
- Pharmacological (vasodilator mimics effect of exercise)
What is Bruce’s protocol?
- Increase the speed and incline of the treadmill every 3 minutes (Stress test)
Contraindications of stress test (4)
- Severe aortic stenosis
- Acute MI
- Severe hypertension
- Atherosclerosis
Why is severe aortic stenosis contraindicated with stress test?
Patient cannot get enough blood volume out to perfuse coronary arteries, brain
Why is an acute MI contraindicated with stress test?
Patient already has increased oxygen demand and inability to deliver it
Why is severe hypertension contraindicated with stress test?
Increases risk for stroke, MI
Complications of stress test (4)
- MI
- CHF (congestive heart failure)
- Cardiac arrest
- Arrhythmias
What is a negative stress test?
What does this mean?
- No symptoms at target heart rate
- Means that signs and symptoms probably not coming from the heart
What is a positive stress test?
What does this mean?
- Symptomatic: Pain, light-headedness
- Stop immediately
What is the target heart rate
80-90% of max predicted for patient’s age level