Exam 1 - Lecture III (CO/CI, PV Loop Diseases) Flashcards
What 2 things determine CO?
VR and pumping effectiveness of the heart. (HR x SV…)
14:00
When thinking about filling pressures, _______ pressures are more important than ______.
Venous (CVP), arterial.
15:15
The _____ the curve, the easier it is to fill the R heart.
Larger
17:30
Thoracic pressure affects our venous return.
What is our normal intrathoracic pressure in mmHg? In cmH2O?
-4 mmHg
5 cmH2O
20:00
Intrathoracic pressure refers to the pressure ______ breaths.
Between
20:30
When you inspire, pleural pressure becomes more _______. VR is ______.
When you expire, pleural pressure becomes more _______. VR is ______.
Negative, increased.
Positive, decreased.
21:00
What things cause right shifts/increase in pressure?
Left shift/decrease in pressure?
Right: opening the chest cavity, + pressure ventilation
*notice cardiac tamponade doesn’t cause a shift but rather a change in slope.
Left: normal breathing, Iron lung
23:00
What is determined by this formula?
Venous Return!
29:00
Is Sodium Nitroprusside a venodilator or arteriodilator?
What would have more of an impact on RAP, an arterial-specific vasodilator or a venous?
What is an example, from lecture, of each?
Venous. (33:45)
Venodilator: NTG (Nitroglycerine) (35:30)
Arteriodilator: Nipride (Sodium Nitroprusside)
*schmidt states that it works on both arteries and veins, but ‘slightly’ more on arteries. (34:20)
If we give a mixed vasodilator, what changes would we expect to see in the CO and RAP?
An overall decrease.
Bc vasodilators decrease RVR.
37:00
If you are constricting the arteries & veins, what happens to the Psf?
To the CO?
An increase in Psf thus increasing the RVR that will cause a slight decrease in CO.
39:00
What happens to heart contractility in heart failure (HF)?
The body compensates with increased _______ activity that increases what?
It decreases. (40:15)
SNS activity
That increases HR and venous tone. (41:00)
Overtime in a failing heart, the body will want to tone down the SNS activity.
Why is it important to tone down the SNS?
And what does the body do overtime to accomplish this?
We dont want to use up our ‘SNS reserve’ (we need it for ADL’s) (42:30) & also, increased SNS puts us at risk for heart attack (45:50)
Overtime, the body (kidney) retains fluid to increase filling pressures. (43:45)
If ‘A’ is normal function, what is ‘B’?
What is the CO at ‘B’?
‘B’ represents no compensation.
CO ~2.5L/min
46:40
What does ‘C’ represent?
What is the CO?
Increased SNS stimulation (in response to HF)
CO is ‘almost normal. (~5L/min)
47:15
Takeaway: “With heart problems, the body will retain fluid.”
If you do something to rid the added volume, like give too much diuretic, what do you think will happen to the patient?
You are taking away their filling pressure, their CO will decrease and their BP will tank.
48:30
In a HF scenario, as you retain more fluid, SNS activity _______ to maintain a ________ CO.
Decreases, stable
50:15
How is CI (cardiac index) determined?
What are the units for CI?
CO / Surface area of the body
L/min/m^2
54:40
When is our cardiac index the highest and what is it? Lowest?
Highest: ~10 yrs age @ 4.5 L/min/m^2
Lowest: the older and more decrepit we get…a healthy 80yr - 2.4 L/min/m^2
54:40
What is the average cardiac index for a relatively healthy 40yr old? (Probably male)
3 L/min/m^2
55:40
What is cardiac index dependent on?
Metabolic rate and SVR/TPR (metabolic rate of the tissue determines SVR - remember the arterioles :)
56:15
An increase in vascular resistance = ______ in CO.
And vice versa.
Decrease
56:45
Properly label the % of CO each organ(s) receive(s).
:)
A: 14%
B: 4%
C: 27%
D: 22%
E: 15%
F: 18%
57:00 (he did not speak to this, but it was ominously on the slide)
From lecture, what diseases/abnormalities cause increased metabolic rate thus increased CO?
BeriBeri, AVShunts, Hyperthyroidism, Anemia, pulmonary disease, paget’s disease.
59:00
What two things/disease (from lecture) will result in a lower CO?
- Removal of extremities (this can be actual removal or applying a tourniquet. (We don’t do this anymore)
- Hypothyroidism (decreases metabolic rate)
61:30
CO is regulated by ________ which is related to _______ consumption.
Metabolism & oxygen consumption
62:20
What is Dinitrophenol?
What does it uncouple?
Why is this unsafe? (What does it do to our metabolism and body temperature?)
Weight loss drug.
Uncouples normal metabolism - were burning glucose inefficiently.
Increases metabolism and increases temperature and we can overheat.
63:00
Takeaway: “Venous volume & CVP are really important in terms of maintaining a normal CO. If we lose that, its difficult to keep BP up and satisfy our metabolic needs.” This is often overlooked.” -schmidt
Why is phenylephrine used as an example after this statement?
Phenylephrine increases SVR = increased BP…
But it is often forgotten that along with squeezing at the arterioles, it also squeezes the veins and that helps with VR (venous return).
Now the heart can pump more volume - VENOUS TONE an VOLUME are REALLY IMPORTANT in maintaining CO.
66:40
Indicate what the red area represents.
A. Decreased preload
B. Increased preload
C. Decreased afterload
D. Increased afterload
B. Increased preload
-notice Increased EDV & increased SV
(Assuming ESV stays normal)
82:00
Indicate what the red area represents.
A. Decreased preload
B. Increased preload
C. Decreased afterload
D. Increased afterload
A. Decreased preload
-notice decreased EDV and SV.
(Assuming ESV stays normal)
84:30
Indicate what the red area represents.
A. Decreased preload
B. Increased preload
C. Decreased afterload
D. Increased afterload
C. Decreased afterload
Notice:
-decreased pressure - aortic valve opens sooner (vent pressure will overcome aortic pressure faster)
-increased SV - more time in ejection (aortic valves stays open longer)
-decreased ESV - from increased SV
87:00
Indicate what the red area represents.
A. Decreased preload
B. Increased preload
C. Decreased afterload
D. Increased afterload
D. Increased afterload
Notice:
-increase pressure - to try & overcome increased afterload
-shortened ejection time - heart squeezes longer to generate more pressure & the AORTIC valves are slammed closed d/t increased aortic pressures.
-increased ESV - from shorted ejection.
85:00
Indicate what the red area represents.
A. Decreased contractility
B. Increased contractility
C. Decreased afterload
D. Increased afterload
A. Decreased contractility
Notice:
-upper left corner loop shift (red bar)
-shorter ejection - smaller SV
-increased ESV
89:20
Indicate what the red area represents.
A. Decreased contractility
B. Increased contractility
C. Decreased afterload
D. Increased afterload
B. Increased contractility
Notice:
- upper left corner loop shift (red bar)
-larger SV - longer ejection time
-decreased ESV - stronger contraction ejects more
88:40
Indicate what the red area represents.
A. Aortic Valve Insufficiency
B. Aortic Valve Stenosis
C. Mitral Valve Stenosis
D. Mitral Regurgitation
D. Mitral Regurgitation
-notice the change in volume during phase II, III & IV
-II: losing LV volume to LA
-III: losing LV volume
-IV: INITIALLY* losing volume bc vent pressure is higher than atrial pressure.
-BP stays ~100 bc increased CVP and volume
91:00
Indicate what the red area represents.
A. Decreased Preload
B. Aortic Valve Stenosis
C. Mitral Valve Stenosis
D. Mitral Regurgitation
C. Mitral valve stenosis
-notice decreased SV from decreased filling
-lower ESV & EDV
95:00
Indicate what the red area represents.
A. Aortic Valve Insufficiency
B. Aortic Valve Stenosis
C. Mitral Valve Stenosis
D. Mitral Regurgitation
A. Aortic Valve Insufficiency/Regurgitation
-notice the increase in volume during Phase IV - mitral valve is closed so this indicates blood is coming from aortic valve
-notice not a lot leaking in @ top of Phase IV - bc pressure difference isn’t significant enough.
98:00
Indicate what the red area represents.
A. Aortic Valve Insufficiency
B. Aortic Valve Stenosis
C. Mitral Valve Stenosis
D. Mitral Regurgitation
B. Aortic Valve Stenosis
-notice higher ESV and elevated pressures, lower SV
What will an afterload reducing agent do to SV? How?
Increase SV by allowing more time for the heart to squeeze.
Slide 14
During inspiration, pulmonary artery pressure (PAP) will _______ and CVP will ______. The amount of blood in the thorax will _______.
Decrease, decrease
increase
(Blood vessels are opened by the expanding chest dropping the internal pressure)
109:00
During early inspiration, the L heart CO _______ also ______ the MAP, temporarily.
Decreases, decreasing
*CO & MAP recover after a couple of heartbeats (115:00)
(The goal on inspiration is to fill the LUNGS with blood, not necessarily the L heart)
113:10, 114:50
