Slide set 3 Flashcards
Lack of sympathetic tone or heart failure would do what to a CO curve?
Right shift and decreased plateau
Increase in sympathetic stimulation or increased pumping effectiveness will cause what in a CO curve?
Left shift and increased plateau
An increase in SVR also causes an increase in
RVR
SVR is also
Afterload
An increased preload will show what variables on the PV loop
Increased SV and EDV; ESV stays the same
A decreased preload will show what variables on the PV loop
Decreased SV and EDV; ESV stays the same
Increased afterload will show what variables on the PV loop
Decreased ejection time and SV; increased time spent in phase II; increased ESV; EDV remains the same
Decrease afterload will show what variables on the PV loop
More time spent in ejection; Increased SV and reduced ESV
Contractility is denoted by what on the PV loop
Upper left hand corner
Increased contractility will show what on the PV loop
Steeper slope with leftward loop shift; increased SV and decreased ESV
Decreased contractility will show what on the PV loop
Reduced slope; reduced SV and increased ESV
What is happening during mitral regurgitation
Any time the pressure is higher in the ventricle than the left atria, blood is backflowing
Why is EF not a good diagnostic for MR
SV is increased
A temporary enhanced filling will eventually cause ______ in MR
eccentric hypertrophy over time
Mild MR
<30 mL backflow
Moderate MR
30-60 mL regurg flow
Severe MR
> 60 mL regurg flow
IABP inflates during
Diastole to help push blood down the atria and perfuse the CAs
IABP deflates during
Systole to create an artificially low afterload
What medications might we give to someone with MR and what considerations should we have
Afterload reducers; caution in patients with CAD and they may have trouble perfusing the CAs
We want to decrease the ________ to reduce regurgitant flow in MR
Delta P
Time spent in ______ can increase mitral regurgitant flow. To combat this we would allow
Systole; permissive slight tacycardia
Mitral regurgitation will show what on a PV loop
Increased SV and EDV; decreased ESV; longer ejection time
Mitral stenosis will show what on a PV loop
Lower SV, EDV, and ESV; left shift - similar to decreased preload
The body compensates for mitral stenosis by
Increasing filing pressures and CVP
Increasing filling pressures of the right heart for MS can cause
Increase in pulmonary pressures, prolonged P wave and a right axis deviation
Mitral stenosis does not have a big effect on
the left ventricle
We want to avoid what intraoperatively with mitral stenosis? Why?
Tachycardia; need as much time in diastole as possible
MS was attributed to rheumatic fever years ago - what might cause it now?
A bad strep infection
Why do we want to avoid a fib in patients with MS
Loss of atrial kick to help filling
What happens during aortic regurgitation
Blood backflows in LV anytime the pressure is higher in the aorta
Compensation for aortic regurg
Fill the heart with more blood
What compensation for aortic regurg may make the backflow even worse
Constricting of vessels to maintain ABP; increased SVR and afterload will further increase delta P
What will you see on a PV loop in AR
Increased SV, EDV, and ESV
What kind of hypertrophy would you find in someone with AR
Eccentric
What medications would we consider in someone with AR
afterload reducers
Pulse pressure is _____ in aortic stenosis
Reduced
What is happening during aortic stenosis
the heart is having to pump against a non compliant valve
Compensation for AS
Increase in filling pressures or an increase in HR
What would see on a PV loop for aortic stenosis
Decreased SV; increased preload and ejection pressures; increased EDV and ESV
Concentric hypertrophy is
Thickening of the heart wall via addition of parallel sarcomeres
Why is preload increased in AS
Thicker heart wall is less compliant to filling
Tachycardia is bad for someone with AS because
Less time spent in diastole; therefore less time perfusing CA
Why is aortic stenosis resistant to CPR
The sequence has been taken out of the contraction; pushing on everything at once
In someone with bad CO and contractility how might we help them out?
Afterload reducer
During early inspiration, what occurs
R heart CO increases 2 fold, L heart CO decreases, PAP decreases due to pulm vessels being pulled open, MAP decreases
PPV affects thoracic pressure and hemodynamics by
Increasing thoracic pressure causing a temporary increase in R and L CO, MAP, and PAP; over time, this decreases VR
Coronary blood flow is equivalent to
70mL/min/100 grams of heart muscle
Normal coronary blood flow rate
225 mL/min
Delta P of aortic pressure and ventricular wall pressure tells us
Coronary blood flow
Temporary retrograde flow of the LCA is caused by
the beginning of systole
X descent
occurs after A wave; drop in pressure during atrial relaxation of mid systole
Y descent
occurs after V wave; drop in pressure d/t ventricular filling at the start of diastole
H plateau
Immediately before A wave; occurs during the middle third of diastole
Overdampening of an A line may be due to
Occlusion or partial occlusion
Underdampening of an A line may be due to
Artifact
When we place a spinal block we are at risk for causing
sympathetic block and knocking out the nerves that pace the heart
The “shortcut” from an AV fistula will cause a decrease in
RVR
At what percentage of blood loss is our CO affected
15%
At what percent of blood loss is our ABP affected
20%
At percent of blood loss would cause fatality if the SNS was knocked out
10-15%
