Random Flashcards
What does ECMO stand for
Extra corporeal membrane oxygenation
What does extracorporeal mean?
Occurring outside the body
When you look at an ECMO machine what do you see
A pair of lungs
What does the ECMO machine do
When blood is pushed into the ECMO machine oxygen is placed into the blood and carbon dioxide is removed
What are the two types of ECMO and which is most common
Venous Venous (VV), and Veno arterial (VA)
VV ecmo is most common
Describe how a VV ECMO works
A Venous Venous ECMO works by taking blood out of the vein, oxygenating it, and then putting it back into the vein
Describe how a VA ECMO works
Blood will be taken out of the vein, passed through the echo machine and then funnelled through an artery back to The Body
Vein > machine > artery > body
What does ARDS stand for
Acute respiratory distress syndrome
What is ARDS
Type of respiratory failure that occurs when the capillary membrane that surrounds the alveoli sac leaks fluid into the sack
What occurs in the alveoli Sac
Gas exchange
What occurs when fluid enters the alveolar sacs? In other words what happens when ARDS occurs in a patient?
There will be a decreased gas exchange, collapse of sac, and hypoxemia (low o2 in blood) which will result in suffering organs
Hypoxaemia
Low oxygen in blood
Hypoxia
Reduced level of tissue oxygenation
What is atrial kick
Atrial kick signifies the contraction of the atria and adds 10 to 30% more blood to the ventricles
What is the pericardium
Fluid filled sac around the heart
Epicardium
Outer visceral layer of heart, flexible outer layer
Describe myocardium
Middle muscular layer
Endocardium
Inner layer of heart, connective tissue
What are the two main coronary arteries
The left coronary artery and the right coronary artery
What does the left coronary artery branch into
The left coronary artery branches into the left anterior descending artery and the circumflex artery
What does the location of the coronary artery determine
Location of the artery determines what area of the heart it provides oxygen to
Coronary arteries break off into smaller what
Collaterals
What are collaterals
Coronary collaterals are tiny specialized blood vessels that connect the larger vessels in the heart
What are the two types of cardiac cells
Electrical cells and mechanical cells
What is the role of electrical cells
Impulse formation and conduction
What is the role of mechanical cells
Muscle contraction
Describe S1
- lub
- closure of AV valves (mitral and tricuspid)
- end of diastole / beginning of ventricular systole
Describe S2
- dub
- closure of semilunar valves (pulmonic and aortic valves)
- end of ventricular systole, beginning of diastole
What is a murmur
Turbulent blood flow
What is cardiac output, normal range, and why do we need it
Cardiac output is the amount of blood pumped into the aorta each minute, normal range is 4 to 8 L per minute, and it is necessary for adequate tissue oxygenation and normal organ function
What are the determinants of cardiac output
Cardiac output is equal to heart rate time stroke volume.
What does stroke volume refer to And what is it influenced by
Stroke volume is the amount of blood ejected from the left ventricle per beat. Stroke volume is influenced by pre-load, after load, and contractility. Normal is 50 to 70 mL per beat
Describe preload and what is it affected by
Reload is the amount of blood volume in the ventricles (End diastolic volume)
Preload is affected by blood volume, venous return, atrial kick, filling time (increased heart rate equals decreased filling time), Amount of myocardial fibre stretch at the end of diastole
Describe afterload and what it is determined by
After load is resistance or pressure the ventricle must overcome to eject it’s blood volume
Determined by size of the vessel (dilation versus constriction) compliance of vessels (stenosis) size and thickness of ventricle walls, (contractility) and volume of blood ejected
Contractility and what is it influenced by
Hearts ability to contract when required
Contractility is influenced by starlings mechanism, sympathetic stimulation, metabolic changes, changes in intracellular calcium, drug therapy
Inotropy
Ability of the myocardial muscle fibres to shorten during systole
Heart failure
Failure of heart to contract effectively as a result of a long-term failure such as untreated valve disfunction or hypertension or short term event such as MI
Angina
Transient inability for the body to meet oxygen demand of the heart. May resolve, may progress
Myocardial infarction
Inability for the body to meet oxygen demand of the heart resulting in damage to cardiac tissue
What kind of valves are anchored to the wall of the ventricle by Cordae tendonae which is attached to papillary muscle
AV valves (mitral and tricuspid valves)
What are the semi lunar valve’s
Aortic and pulmonary valves
What are the AV valves
Mitral and tricuspid valve
The Semi lunar valve’s differ from the AV valves as the semi lunar valve’s have no
Chordae tendonae
What does stenosis mean
Narrowing
Stenotic valves restrict the forward flow of blood because
They are unable to open fully
Why does stenosis impact the heart function over time
- increase cardiac workload to pump against the high afterload (Increased afterload of a tree out or ventricles due to narrowing)
- obstruction of blood flow results in backup of blood and increased pressure in the affected chambers - Eventual hypertrophy of the atria or ventricles
Regurgitation
Valves do not close properly resulting in the backward flow of blood
Why is regurgitation bad
Increased volume and pressure behind the valve
Increased cardiac workload in an effort to maintain adequate cardiac output
Ebstein’s anomaly
Congenital heart defect in which tricuspid valve has malformed and displaced causing regurgitation
Atresia
Absence or closure of valve orifice, often tricuspid valve
