Cardiac Review c Nicole Flashcards
What are some determinants of MAP?
- map= (CO X SVR) + CVP
- CVP doesn’t really mean anything in this equation
- most of MAP from CO X SVR
- remember breakdown of MAP…
•Your patient’s preoperative echo shows a mitral valve opening of 0.7 cm2. During your preoperative assessment your patient complains of orthopnea requiring sleeping upright at night. The EKG shows atrial fibrillation. Your anesthetic plan may include which of the following medications?
a) Ketamine for induction
b) Sevoflurane at 2 MAC for pulmonary bronchodilation
c) 500 cc rapid fluid bolus for acute hypotension
d) Esmolol for heart rate control
e) All would be appropriate to include in the plan
Answer- D esmolol
a) Ketamine for induction- this increases SNS,. increases HR, not wanted in mitral stenosis
b) Sevoflurane at 2 MAC for pulmonary bronchodilation- this is way too high of a VA and you will lose SVR, causing decrease afterload= bad
c) 500 cc rapid fluid bolus for acute hypotension- Mitral stenosis pt don’t tolerate a rapid fluid bolus. distends atrium. slow fluid ok
d) Esmolol for heart rate control- best answer because we want slow HR to allow hear tot have time to empty
e) All would be appropriate to include in the plan- not all are appropriate
Phsyiologic expectations for Mitral Stenosis?
- Atrial enlargement–> atrial fibrillation
- pulmonary congestion–> pulm HTN–> R ventricular failure–> DOE (pulmonary congestion)
- Decreased SV due to decreased LV volume, stress induced tachycardia and loss of L atrial kick
- Severe stenosis MV <1.5 cm2
Goals of mitral stenosis?
- Preload- increase (any cardiac issue, everyone gets good preload)
- HR- slow- helps heart move past obstruction
- Afterload- High- your HR has to be low, and SV is fixed. In order to maintain good BP in this pt, need high afterload (go back to pic on determinants of MAP)
- Contractility- maintain
- Rhythm- NSR
What are specialty considerations ofr the mitral stenosis patient?
- Avoid worsening pulm HTN
- if you give fluid too fast, causes increase in LA and increase in pulm congestion
- HOW to avoid?!?
- avoid
- hypoxia
- hypercarbia
- acidosis
- uncontrolled pain–> release of catecholamines which will worsen pulm HTN
- shivering
- hyperinflation lung–> push on pulmonary vasculature, closing this off, worsens pulm HTN
- avoid
- Avoid rapid fluid administration
- Positioning–> head down position–> gives natural fluid bolus–> increase DOE
•In the preceding scenario (Your patient’s preoperative echo shows a mitral valve opening of 0.7 cm2. During your preoperative assessment your patient complains of orthopnea requiring sleeping upright at night. The EKG shows atrial fibrillation.
: What anesthetic considerations would be appropriate for this patient (select 2)?
a) Arterial line monitoring
b) Noninvasive blood pressure monitoring
c) Ventilator-controlled ventilation
d) Spontaneous ventilation
A &C
- Aline- any severe valuvlar d/o gets an aline
- ventilator controlle ventilation- pulm HTN c hypercarbia–> we don’t want to increase PVR
•Your patient has a history of severe aortic stenosis. Preoperative evaluation demonstrates a history of syncope and episodes of angina. Anesthetic management for a colon resection includes which of the following?
a) Myocardial depression is desired to decrease oxygen demands
b) Epidural anesthesia for postoperative pain control
c) High opioid induction technique
d) Nitroglycerin drip for coronary perfusion
ANSWER- C
a) Myocardial depression is desired to decrease oxygen demands- we do want to decrase demand, but myocardial depression is notthe way to do it
b) Epidural anesthesia for postoperative pain control- this can cause a sympathomimectomy, decreasing afterload too much which is detrimental to AS pt. If mild/mod AS, may consider epidural
c) High opioid induction technique- great choice, some bradycardia but otherwise preserve cardiac function
d) Nitroglycerin drip for coronary perfusion- bad for AS because of decrease afterload
Aortic stenosis physio expectations?
Triad:
- Syncope= exercise induced drop in SVR and uncompensated decrease in CO due to low SV (from decrease LV volume)
-
Angina= due to increase O2 demand (LVH) and decreased delivery by compression of subendothelial vessels by increased L vent pressure
- coronaries themselves are fine
- DoE= due to decreased CO
- L Ventricle Hypertrophy
- Normal Aortic valve is 2.5-3.5 cm2
- severe <0.8 cm2
Aortic stenosis anesthetic goals?
- Preload- full
- HR- Normal/low
- nicole says she doesn’t touch whatever their preop HR is, however probably not the answer on the test
- with high HR, worsen outflow and increase demand on heart
-
too slow HR, will cause overdilation of heart
- 30-40 too slow, won’t be able to compensate
- Afterload- high
- this helps pull valve open and decrease stenosis, increase outflow
- help with coronary perfusion
- Contractility- maintain
- Rhythm- NSR–> typically not an issue
Specialty considerations ofr aortic stenosis?
- Aggressive tx of junctional/brady arrhythmias.- loss of atrial kick, get huge drop in BP
- SVT cardioversion
- Lidocaine/amiodarone/defib for vent dysrhythmias
- Codes: Bad news
•Your patient with severe mitral regurgitation shows the following intraoperative vital signs: arterial blood pressure: 78/50, HR: 100. Preoperative bp was 150/80 and HR 85. Preoperative echo shows moderate left ventricle dysfunction. Maintenance anesthetic is mixture of N20 and 0.6 Isoflurane. Which of the following interventions would be appropriate in management for this patient?
a) Dopamine infusion
b) Phenylephrine infusion
c) Removal of N20 and increase Isoflurane to 1 MAC
d) No changes required, patient will compensate
answer A
a)Dopamine infusion- vasodilate good for coronary perfusion, dopaminergic receptors at low dose. Mod dose get B1 stim –> increase HR. High dose get alpha–> increase afterload- this does violate one of the rules but best choice
b) Phenylephrine infusion- this will incrase afterload and decrease HR. Both things we do not want
c) Removal of N20 and increase Isoflurane to 1 MAC- the proposed anesthetic in question is actually a very good combo for mod LV dysfunction. N2O is added to decrease the amount ISO needed and decrease cardiac depressant.
d) No changes required, patient will compensate- you need to do something, this BP is too low
Mitral regurgitation physio expectation?
- Decreased forward L Vent –> decreased SV and CO
- Atrial volume overload –> pulm congestion
- Atrial fibrillation common
- Less dependent on atrial kick than stenosis
- Fraction of regurg flow depends on…..
- size of orifice- no control over this
- HR- able to control
- Pressure gradient– able to control.
- Severe regurg if 60% of regurg present
What are specialty considerations in mitral regurgitation?
•Monitor V wave on PA cath (if severe only)
Goals of mitral regurg?
- Preload- incrase
- HR- increase
- aggressive bradycardia treatment. bradycardia increases amt regurg in heart
- keep everything moving forward
- afterload- decrease
- think back to MAP–> high HR needed, high CO and allows you to drop afterload
- contractility- support/maintain
- rhythm- NSR <– probably not going to get this
- afib high rate ok- not as dependent on atrial kick like stenosis
•Your patient has a history of idiopathic hypertrophic subaortic stenosis (IHSS). Intraoperative blood pressure by arterial line shows 72/42 with heartrate 99. Appropriate management includes which two of the following?
a) Dopamine
b) Crystalloids
c) Phenylephrine
d) Epinephrine
answer- b and c
a)Dopamine
b)Crystalloids- want fluid to fill heart, expand LV and improve BP
c)Phenylephrine- need increase afterload to help move blood forward. also will decrease HR
d)Epinephrine
