Oral Review: Cardiac

Question 1

What are some factors that influence the heart’s O₂ demand?

Answer 1

1. HR
2. SVR
3. Filling pressures
4. Preload and afterload
5. Contractility

Question 2

What are some factors that influence the heart’s O₂ supply?

Answer 2

1. HR
2. CO
3. Coronary perfusion pressure (MAP - CVP)
4. O₂ carrying capacity (Hgb)
5. FiO2

Question 3

What is the most important factor for supply and demand in IHD/CAD pts?

Answer 3

HR; affects both supply and demand

Question 4

Compare and contrast stable, unstable, and prinzmetal angina:

Answer 4

1. Stable:
   
   • at least 60 days no ∆ in frequency,
   • duration or other factors;
   • associated with a fixed narrowing (usually 75%+)
   • relieved by rest, NTG
2. Unstable:
   
   • becoming more frequent, longer, or more severe
   • occuring at rest or with less exertion;
   • associated with an unstable plaque/thrombosis;
   • signals impending MI
3. Prinzmetal:
   
   • coronary vasospastic disease

Question 5

What is our fundamental goal for IHD/CAD pts?

Answer 5

Balancing O₂ supply with O₂ demand

Question 6

Discuss regional anesthesia in IHD/CAD patients:

Answer 6

1. Regional anesthsia is acceptable as long as we treat ⇣ in SBP to keep within 20% of baseline.
2. Sympathectomy can actually help, but we need to make sure fluids counteract hypovolemia leading to hypotension
3. Good drugs for this include ephedrine and phenylephrine
   
   • Especially phenylephrine: no inotropy/chronotropy = does not affect O₂ demand at all

Question 7

Discuss opioids’ effects on cardiac function:

Answer 7

1. Cause dose-dependent bradycardia and vasodilation
2. No independent ⇣ in CV function
3. When used with N₂O or benzos
   
   • cause ⇣ CO and ⇣ BP

Question 8

Discuss induction in an IHD/CAD patient:

Answer 8

1. Blunt SNS outflow as much as possible prior to laryngoscopy,
   
   • using lidocaine, fentanyl, and/or esmolol,
2. and Keep it SHORT

Question 9

Cardiovascular goals for IHD/CAD patients:

Answer 9

1. Avoid tachycardia!!
   
   • Low-normal HR needed to ⇣ O₂ demand.
2. Maintain normal preload;
   
   • preload needed to fill ventricle and maintain SV (Frank-Starling)
   • ⇡ preload = increase demand
   • ⇣ preload = decreased coronary profusion
3. Maintain normal afterload;
   
   • afterload needed to maintain diastolic pressure and ⇡ O₂ supply to coronaries
4. Decrease contractility if LV function is normal;
   
   • this will ⇣ O₂ demand.

Question 10

Four hemodynamic effects of all volatile agents:

Answer 10

1. Dose-dependent ⇣ in contractility
2. Dose-dependent ⇣ in SVR
3. Dose-dependent ⇡ in CBF
4. May Sensitize heart to epinephrine

Question 11

IA of choice in cardiac anesthsia is usually:

Answer 11

Isoflurane

Question 12

Emergence and post-op considerations for IHD/CAD patients:

Answer 12

1. Shivering and pain will ⇡ O₂ demand; minimize them
2. Supplemental O₂ will ⇡ O₂ supply
3. Smooth emergence
   
   1. consider low-end dosing of anticholinergic w/ reversal agent
   2. lidocaine prior to extubation
   3. extubate deep if possible

Question 13

EKG leads and what they evaluate:

Answer 13

• II, III, aVF:
  
  • ​RCA ⇢ inferior wall MI
    
    • R atrium, R ventricle,
    • SA node, AV node
• I, aVL:
  
  • Circumflex ⇢ lateral wall MI
    
    • lateral L ventricle
• V3-V5:
  
  • ​LAD ⇢ anterior wall MI
    
    • ​⇢ anterolateral L ventricle

Question 14

Three factors that determine LV outflow obstruction in IHSS:

Answer 14

1. Contractility
2. Preload
3. Afterload

Question 15

What is our fundamental goal for IHSS patients?

Answer 15

• Decreasing the LV outflow tract obstruction

(which is worsened by ⇡ contractility and ⇣ preload/afterload)

Question 16

Discuss regional anesthesia for IHSS patients:

Answer 16

1. Okay to do
   
   • but be cautious to offset ⇣ preload/afterload with good fluid management otherwise you can worsen the LV outflow tract obstruction

Question 17

Anesthetic/cardiovascular goals for IHSS patients:

Answer 17

GOAL: minimize LV outflow obstruction

1. Decrease HR = ⇣ O₂ demand
2. High preload = the heart needs the volume
3. Normal to high afterload = normal SVR to counter the high ejection velocity and preserve coronary perfusion
4. Decrease contractility to ⇣ O₂ demand

Question 18

Discuss induction in IHSS patients:

Answer 18

1. Heavy premedication to ⇣ SNS outflow and strong SNS blunting before laryngoscopy
2. Consider use of VAs and esmolol before intubation
3. Etomidate is drug of choice
4. Avoid sudden ⇣ in SVR
   
   • i.e. from propofol, STP
5. AVOID
   
   • ketamine
   • sympathomimetics (pancuronium)
   • histamine releasers (miva, atra)

Question 19

Maintenance drugs to use in IHSS patients:

Answer 19

1. Volatiles:
   
   • deep (1-1.5 MAC) of any of the drugs, just watch the SVR;
   • Deepen VA for hypertension
   • Lighten VA junctional rhythm
2. Opioids:
   
   • do not use as sole anesthetic d/t ⇣ SVR without myocardial depression;
   • use with VAs or benzos to produce myocardial depression without sigificant ⇣ SVR
3. Phenylephrine a good choice
   
   • ⇡ SVR without inotropic/chronotropic effect
4. Fluids are huge
   
   • hypotension usually = hypovolemia for these patients
5. Use propranolol or esmolol
   
   • for persistant tachycardia

(Treat hypotension first with fluids and then with phenylephrine!)

Question 20

Maintenance drugs to avoid in IHSS patients:

Answer 20

1. Inotropes
2. Calcium agonists
3. Beta agonists (ephedrine, dopamine, dobutamine)
4. NTP (will ⇣ SVR)
5. NTG (will ⇣ Preload)

Question 21

Signs/symptoms of forward vs. backwards failure:

Answer 21

1. Forward failure
   
   1. think ⇣ CO, ⇣ end organ perfusion:
      
      • fatigue
      • hypotension
      • oliguria
      • RAAS activation
2. Backwards failure:
   
   • ⇡ filling pressures
   • LV dilation
   • mitral regurgitation

Question 22

Anesthetic/cardiovascular goals for Dialated Cardiomyopathy patients:

Answer 22

1. Normal to high-normal HR:
   
   • CO is HR dependent… SV will be small
2. Normal to high-normal preload:
   
   • if SVR ⇡ too much, pulm edema is a risk
3. Normal (NOT ⇡) afterload:
   
   • don’t ⇣ SVR too much, though, or it will ⇣ preload too
4. Increase contractility:
   
   • heart is weak and needs as much force as it can get

Question 23

Discuss induction in Dialated Cardiomyopathy patients:

Answer 23

1. Be careful with opioids + benzos as the combination can ⇣ myocardial contractility
2. Etomidate is drug of choice
3. Choose NMB with minimal CV side effects
   
   1. vec, roc, cisat
4. Avoid sympathomimetics (ketamine, pancuronium)
   
   • Whyyy???

Question 24

Maintenance drugs to use and avoid in Dialated Cardiomyopathy patients:

Answer 24

1. Treat tachycardia with esmolol
   
   1. Use filling pressures to guide fluids
2. Treat hypotension with ephedrine or phenylephine (go slow on phenylephrine; will ⇡ SVR)

Question 25

Four stages of pericardial disease:

Answer 25

1. Dry stage / acute pericarditis 2. Effusion stage 3. Cardiac tamponade 4. Absorption stage / constrictive pericarditis

Question 26

Discuss regional anesthesia for pericardial disease patients:

Answer 26

* Not usually an option due to the **emergent** nature of the surgery and existing hypotension. * **Pericardiocentesis** can be done under **local** anesthesia, however.

Question 27

Anesthetic/cardiovascular goals for pericardial disease:

Answer 27

1. **Normal to high-normal HR:** * AVOID bradycardia, * **CO** will depend much more on **HR** than **SV** 2. **Normal to high-normal preload:** * Give fluids! * need the volume to make **SV** as large as possible 3. **Maintain inotropy:** * can’t fill as well as it wants, but we can keep it squeezing 4. **Avoid myocardial depression**

Question 28

Discuss induction in patients with pericardial disease:

Answer 28

1. **No pre-op meds!** 2. Need as much **SNS** **outflow** as possible! 3. **Ketamine** is good - ⇡ contractility, ⇡ HR * Might need low dose propofol + ketamine + LMA until the effusion is drained, before turning on VAs 4. **Pancuronium** if you need an NMB, but that’s unlikely 5. Keep in mind that **PPV** can cause **hypotension** in the presence of tamponade (decreased venous return) 6. Keep in mind that once theeffusion is draind they are likely to become **HYPERtensive**!!! Be ready for it!

Question 29

Pre-op evaluation for mitral stenosis:

Answer 29

1. Exercise tolerance 2. S/s of CHF * Compensatory SNS ⇡ like anxiety, diaphoresis, resting tachycardia 3. Cardiac dysrhymias like a-fib 4. Angina from ⇣ O₂ supply

Question 30

Discuss regional anethesia for mitral stenosis pts:

Answer 30

1. **Not a good choice**; * they are **pre-load dependent** and need to maintain SVR. * Will need good fluid management if necessary

Question 31

Anesthetic/hemodynamic goals for mitral stenosis:

Answer 31

**Slow - Tight - Full** * **Slow**: * **AVOID** tachycardia to allow for diastolic filling * **Tight**: * maintain **SVR** to preserve diastolic pressure and coronary filling * **Full**: * maintain **preload** to ensure enough volume for diastolic filling (**Avoid hypoxemia/hypoventilation to prevent pulm HTN and right heart failure**)

Question 32

Discuss induction in patients with mitral stenosis:

Answer 32

1. Avoid drugs that ⇡ HR or abruptly ⇣ SVR: * ketamine, pancuronium, and all histamine-releasing drugs (miva, atra) * 2. Be sure to **blunt** **laryngoscopy** reflexes 1. (lido, opioids, induction agent)

Question 33

Maintenance drugs to use and avoid in mitral stenosis patients:

Answer 33

* **Low** **dose** **VAs** titrated slowly upwards * IV **fluids** and **phenylephrine** to counteract VA vasodilation * **Inotropes** like **dobutamine** to ⇡ contractility if needed (less increase in HR) * **Avoid** **desflurane** - can really ⇣ ⇣ SVR and ⇡ HR (reflexive) esp if rapid ⇡ in concentration

Question 34

Pre-op evaluation for mitral regurg:

Answer 34

1. Exercise tolerance 2. S/s of CHF 1. Compensatory SNS ⇡ incl. anxiety, diaphoresis, resting tachycardia 3. Cardiac dysrhythmias, esp. **a-fib** 4. Angina d/t insufficient O₂ supply

Question 35

Discuss regional anesthesia for mitral regurg patients:

Answer 35

**Okay to use**, but make sure to keep fluid volume up to avoid ⇣ SVR

Question 36

Anesthetic/hemodynamic goals for mitral regurg:

Answer 36

**Fast - Full - Forward** 1. **Fast**: keep HR high-normal (**80-90bpm**) * **CO** is going to be very **HR** dependent for them 2. **Full**: keep preload high * to **fill the tank** and **⇡ SV** as much as possible 3. **Forward**: maintain **low-normal SVR** * in order to promote **forward** **flow** of SV and minimize backwards flow * V-wave will reflect regurgitant flow 4. **Minimize myocardial depression**

Question 37

Drugs to use and avoid in patients with mitral regurg:

Answer 37

**USE** 1. **NMB** with stable CV profile or pancurionium which will ⇡ HR 2. For **HTN**, use hydralazine - no HR effect, and will ⇣ afterload more than preload 3. **Isoflurane** is VA of choice d/t hemodynamic effects * **N₂O** + **low** **dose** **VA** to minimize myocardial depression * for **severe** **dysfxn**, opioid or TIVA technique 4. **Inotropes** if ⇡ contractility needed * **dobutamine**, **isoproterenol** **AVOID** 1. high dose opioids (will ⇣ HR), beta blockers (will ⇣ HR)

Question 38

Pre-op evaluation for aortic stenosis:

Answer 38

1. Exercise tolerance 2. S/s of AS 1. Syncope, Angina, Dyspnea on exertion 3. Cardiac dysrhythmias

Question 39

Discuss regional anesthesia in aortic stenosis patients:

Answer 39

NOT A GOOD CHOICE * sympathectomy **⇣ SVR** which leads to **⇣ venous return** and **⇣ perfusion pressure** * the heart with AS is already susceptible to **ischemia** d/t ⇡ O₂ demands

Question 40

Anesthetic/hemodynamic goals for aortic stenosis:

Answer 40

**Maintain HR, SVR, preload, and avoid ⇣ CO at all costs** 1. **Maintain NSR** * these pts absolutely need **atrial kick** for LVEDV (remember more volume = more force) * **AVOID** junctional and a-fib (they will be hard to get back) * **AVOID** tachycardia 2. Maintain preload and afterload; * **Adequate SVR** → need the pressure to perfuse coronaries (avoid sudden decreases) * Maintain **preload** to maintain venous return and optimize LV filling

Question 41

Induction drugs to use/avoid in aortic stenosis patients:

Answer 41

* **BP is HR dependent** * if they become bradycardic treat with atropine or glyco * **Etomidate** = drug of choice * **Phenylephrine** = if BP drops * **Opoids** are gread because they will decrease the HR * **NDMR**: Vec, roc, cis (no CV effects)

Question 42

Maintenance drugs to use/avoid in aortic stenosis patients:

Answer 42

1. **Anestheisa maintained with** * **N2O** + **opioids** * or if they have significant LV dysfunction a **High Opioid Technique** 2. **NMB** - w/o CV side effects (**Roc, Vec, Cis-atra**) * **Bad Choice** = Pancuronium - stimualtes Ganglion and increases HR 3. **Hypotension**: * treat with an alpha agonist * **Phenylephrine** (it DOES NOT increase HR) 4. **Treat Junctional Rhythm/Bradicardia** 1. **​**(Glycopyrolate, Atropine, Esmolol) →BP is HR dependent 5. **SVT** - treat promptly with cardioversion 6. Aortic Senosis has a propensity to develop **ventricualar arrythmias** 1. **​ALWAYS** have Lidocaine and Amioderone 2. **ALWAYS** have a Defibrilator Availible

Question 43

Discuss regional anesthesia in aortic regurg:

Answer 43

• Discouraged due to unpredictability of ⇣ SVR reponse

Question 44

Anesthetic/cardiovascular goals for aortic regurg:

Answer 44

**Maintain forward flow** 1. **High-normal HR**; * will keep CO up even if SV is small 2. **Maintanin normal preload** * caution...too much = pulmonary edema 3. **Maintain normal SVR** 1. **​**avoid sudden ⇡ to promote forward flow and coronary perfusion 4. **Minimize myocardial depression**

Question 45

Induction drugs to use/avoid in aortic regurg patients:

Answer 45

1. **Etomidate** is drug of choice 2. **Ketamine** may be useful to provide ⇡ HR 3. **High opioid + pancuronium** for long cases

Question 46

Maintenance drugs to use/avoid in aortic regurg patients:

Answer 46

1. **Isoflurane** better for long cases 1. (minimal cardiac depression, maintains CO, preserves baroreceptor reflex) 2. **Sevoflurane** for shorter cases 3. **Opioid** + **benzo** for severe LV dysfxn 4. **NTP** intra-op for **hypertension** to keep SVR from getting too high 5. **Atropine** for bradycardia (promptly)

Question 47

Describe hypertensive crisis:

Answer 47

**DBP is acutely \> 130** 1. **Can be from:** * MH * thyroid storm * pheochromocytoma * eclampsia, etc 2. **Can result in:** * encephalopathy * CHF * SAH * renal insufficiency

Question 48

Treatment for hypertensive crisis:

Answer 48

* **SNP** 0.5 - 10 μg/kg/min * ​drug of choice d/t short DoA * **NTG** 5 - 200 μg/kg/min * **Labetalol** 40 - 80mg q10min (⇣ DBP by **20% i**n first **2 hours** then gradually to baseline over **24-48 hours**)

Question 49

Pre-op evaluation for HTN:

Answer 49

* Is it **controlled** well enough for surgery? * Review **medications** and consider anesthetic implications * Evaluate for evidence of **end-organ damage**

Question 50

Induction drugs to use/avoid in HTN:

Answer 50

1. **Lidocaine**, **opioids**, or **VA** to make sure patient is deep before laryngoscopy 2. Consider **100-200mg esmolol** prior to laryngoscopy 3. AVOID ketamine

Question 51

Maintenance drugs to use/avoid in HTN:

Answer 51

1. Keep **phenylephrine** and **ephedrine** handy 2. Use **easily** **titratable** VA (**sevo/des**) 3. **Balanced** **technique** to keep VA concentration low 4. **Intra-op hypertension:** usually from **pain** * ​​⇡ VA and use **opioids** or **antihypertensives** 5. **Intra-op hypotension**: * **⇣ VA** concentration, supplement **fluids** if needed, **check rhythm**, consider **sympathomimetics**