Mod2: Cardiac Surgery - BASIC ANESTHESIA TECHNIQUES

Question 1

_{BASIC ANESTHESIA TECHNIQUES}

The goals of induction are for it to be?

Answer 1

A smooth transition from awake to sleep

With minimal hemodynamic effects

Reliable loss of consciousness

Sufficient depth of anesthesia to prevent SNS response to laryngoscopy/intubation

Question 2

_{BASIC ANESTHESIA TECHNIQUES}

Which anesthetic technique is generally used to acheive the goals of induction?

Answer 2

Moderate to high-dose narcotic technique

^{(<em>Fentanyl</em> 10-100 mcg/kg)}

Supplemented with Etomidate (0.1-0.3 mg/kg) or

Propofol (1-2.5 mg/kg)

Depending on the LV function

Question 3

_{BASIC ANESTHESIA TECHNIQUES​}

At which point during induction would a muscle relaxant be administered?

Answer 3

Once loss of consciousness is confirmed

Remember, “Hearing is the last thing to go” , so

Be midful of conversations at this time

Question 4

_{BASIC ANESTHESIA TECHNIQUES​}

Which muscle relaxants are typically used for induction of anesthesia in cardiac surgery?

Answer 4

Rocuronium

^{(0.6-1.2 mg/kg)}

Succinylcholine

^{(0.5-1 mg/kg) if RSI needed}

Question 5

_{BASIC ANESTHESIA TECHNIQUES​}

Which other drugs may be used to compliment anesthesia induction in cardiac surgery?

Answer 5

Esmolol, Lidocaine, NTG

Question 6

_{BASIC ANESTHESIA TECHNIQUES}

Why is the High dose Narcotic Technique superior to others?

Answer 6

Associated with minimal cardiac depression

Has the ability to provide hemodynamic stability

Question 7

_{BASIC ANESTHESIA TECHNIQUES}

What are the drawbacks of the High dose Narcotic Technique?

Answer 7

Do not consistently prevent hypertensive responses during periods of high stimulation

Therefore, must be paired with inhalational agents and vasodilators

Do not provide amnesia; patient recall remains a potential problem; hence must be paired with Benzodiazepines

May produces significant bradycardia; which may be exasperated by other drugs (e.g., Vecuronium)

May cause Chest wall rigidity, especially high doses; consider low-dose (priming) of non-depolarizing muscle relaxant prior to administration (e.g., 5mg of Rocuronium)

May prolongs emergence and extubation in the ICU; which is a bad thing because most centers/surgical teams would like to “fast track” patients, extubating within 4-6 hours post-op

Question 8

_{BASIC ANESTHESIA TECHNIQUES}

Why does the High narcotic technique require pairing with with inhalational agents and vasodilators?

Answer 8

It does not consistently prevent hypertensive responses during periods of high stimulation

Question 9

_{BASIC ANESTHESIA TECHNIQUES}

Why does the High narcotic technique require pairing with Benzodiazepines?

Answer 9

Because it does not provide amnesia

Patient recall remains a potential problem

Question 10

_{BASIC ANESTHESIA TECHNIQUES}

The High narcotic technique may produces significant bradycardia; which may be exasperated by other drugs (e.g.,

Answer 10

Vecuronium

Question 11

_{BASIC ANESTHESIA TECHNIQUES}

The High narcotic technique may cause Chest wall rigidity, especially high doses. Which drugs could be given prior to administration of narcotics to prevent this chest wall rigidity?

Answer 11

Low-dose (priming) of non-depolarizing muscle relaxants

(e.g., 5mg of Rocuronium)

Question 12

_{BASIC ANESTHESIA TECHNIQUES}

The High narcotic technique may prolong emergence and extubation in the ICU. Why is this a bad thing?

Answer 12

Most centers/surgical teams would like to “fast track” patients, extubating within 4-6 hours post-op

Question 13

_{BASIC ANESTHESIA TECHNIQUES}

Between Fentanyl and Sufentanil which is more used for High dose Narcotic Technique?

Answer 13

Fentanyl > Sufentanil

Question 14

_{BASIC ANESTHESIA TECHNIQUES}

Since the time from when the pt is anesthetized to when the incision is made is variable, is it a reasonable idea to reduce the depth of anesthesia? Explain.

Answer 14

Time from when the pt is anesthetized to when the incision is made is variable

Pt must be shaved, prepped and draped during this time

There will be low levels of stimulation

Keeping in mind the potential for recall, it’s a reasonable idea to reduce the depth of anesthesia in an attempt to reduce the amount of vasodilation from the anesthetic agents

Question 15

_{BASIC ANESTHESIA TECHNIQUES}

Why should you consider using lower dose of Volatile anesthetics when utilizing the Mixed IV/Inhalational technique to maintain anesthesia Pre-incision?

Answer 15

Volatile anesthetics may cause myocardial depression

Consider lower levels

Question 16

_{BASIC ANESTHESIA TECHNIQUES}

What are advantages of using lower dose of volatile anesthetics when utilizing the Mixed IV/Inhalational technique to maintain anesthesia Pre-incision?

Answer 16

Ischemic preconditioning

Decreased myocardial O2 demand with volatile anesthetics

Question 17

_{BASIC ANESTHESIA TECHNIQUES}

Which drugs could be intermittently given as boluses when utilizing the Mixed IV/Inhalational technique to maintain anesthesia before incision?

Answer 17

Intermittent boluses of opioids and muscle relaxants

^{Fentanyl 10-100 mcg/kg}

^{Sufentanil 5-20 mcg/kg}

Question 18

_{BASIC ANESTHESIA TECHNIQUES}

In the maintenance of anesthesia before incision, and because of the low levels of stimulation, hypotension may occur. How should it be managed?

Answer 18

Reduce depth of anesthesia

Administer vasopressors

^{(especially if the pt has ventricular dysfunction or aortic stenosis)}

MAKE SURE TO ANTICIPATE INCISION

Question 19

_{BASIC ANESTHESIA TECHNIQUES}

How should the arms be positioned?

Answer 19

Tucked to the side

Make sure padding is appropriate to avoid nerve damage to either the ulnar or radial nerve

Question 20

_{BASIC ANESTHESIA TECHNIQUES}

Pt is also pulled down to the foot of the bed, and either and Ether screen or “male stand-like” table is placed at the head of the table. What should you be concerned about?

Answer 20

Making sure all IV lines and the ET tube are free from tugging

Question 21

_{BASIC ANESTHESIA TECHNIQUES}

The pt will also be completely exposed for positioning, prepping, and draping. What should you be concerned about?

Answer 21

Hypothermia

Temperature is very important to monitor

Warm the room or turn the underbody water warmer on to keep an appropriate temperature

Question 22

_{PREBYPASS PERIOD - Incision to bypass}

The minimal stimulation phase is followed by high stimulation that can have which effects?

Answer 22

Tachycardia

HTN

Ischemia

Question 23

_{PREBYPASS PERIOD - Incision to bypass}

The minimal stimualtion phase is followed by high stimulation that can produce Tachycardia, HTN, Ischemia. How should this period be managed?

Answer 23

Anticipate events

Deepen anesthesia

Use narcotics

Use vasodilators in moderation

Question 24

_{PREBYPASS PERIOD - Incision to bypass}

The anesthetic agents should be adjusted appropriately to anticipate incision, sternotomy/sternal retraction, Pericardotomy/Cardiotomy, Aortic root dissection, taking caution to not overdose the pt, as this could cause:

Answer 24

Hypotension

Question 25

_{PREBYPASS PERIOD - Incision to bypass} NTG is typically given in increments to avoid substantial drop in BP. Why is NTG a great agent to treat acute HTN?

Answer 25

It has F**ast onset, and** **Short duration** of action

Question 26

_{PREBYPASS PERIOD - Incision to bypass} During sternal sawing, the anesthesia provider must deflate the lungs by switching the ventilator off; why?

Answer 26

To reduce chance of sawing injury to the right ventricle

Question 27

_{PREBYPASS PERIOD - Incision to bypass} Wy would the exhalation limb of breathing circuit be disconnected during sternal sawing?

Answer 27

To facilitate complete deflation of lungs

Question 28

_{PREBYPASS PERIOD - Incision to bypass} T/F: During during sternal sawing the APL must be completely opened

Answer 28

True

Question 29

_{PREBYPASS PERIOD - Incision to bypass} With Redo open heart procedures, the lungs can remain inflated. Why?

Answer 29

An **oscillating saw** used It moves backward and forward instead of rotating in a full circular path like a standard sternal saw Use of an Oscillating saw reduces the chance of damage to vessels adhering to the posterior aspect of the sternal wall *Consider lowering tidal volumes*

Question 30

_{PREBYPASS PERIOD - Incision to bypass} T/F: Use of an Oscillating saw reduces the chance of damage to vessels adhering to the posterior aspect of the sternal wall

Answer 30

**True** However, damage to vessels adhering to the posterior aspect of the sternal wall remains a potentially serious risk because scarring can lead to cutting or tearing of intra-thoracic vessels

Question 31

_{PREBYPASS PERIOD - Incision to bypass} In the event that injury does occur to a major vessel, you must be ready to:

Answer 31

**Resuscitate** the pt

Question 32

_{PREBYPASS PERIOD - Incision to bypass} Which pts will typically have blood available in the room?

Answer 32

Pts with a **hx of open heart surgery**

Question 33

_{PREBYPASS PERIOD - Incision to bypass} The surgeon will also require prepping of the femoral area for potential cannulation or they may even place guide wires in the femoral vein and artery in anticipation of:

Answer 33

**Injury to the major vessels** Femoral vessels prepped for potential cannulation

Question 34

_{PREBYPASS PERIOD - Incision to bypass} You must have heparin ready because:

Answer 34

Pt must be **heparinized** prior to the initiation of bypass Pre-drawn heparin available in case of **crashing on pump**

Question 35

_{PREBYPASS PERIOD - Incision to bypass} Why must Anticoagulation be established prior to CPB?

Answer 35

To prevent both the **formation of clots** in the bypass pump and **DIC**

Question 36

_{PREBYPASS PERIOD - Incision to bypass} What's the drug of choice for anticoagulation during bypass? How is it dosed?

Answer 36

**Heparin** is the drug of choice Dosed *300-400 units/kg*

Question 37

_{PREBYPASS PERIOD - Incision to bypass​} After heparin administration, when and where should ACT be drawn? What should the minimal ACT value be to safely commence bypass?

Answer 37

An ACT should be drawn from **central line** access Should be done **3-5 minutes** after heparin administration ACT must be **at least 400 seconds** to safely commence bypass

Question 38

_{PREBYPASS PERIOD - Incision to bypass​} What should be done if ACT \> 400sec is not acheived?

Answer 38

Redose 100 units/kg up to three times

Question 39

_{PREBYPASS PERIOD - Incision to bypass​} If the pt is consistently below 400sec, despite redosing, what should be considered?

Answer 39

Heparin resistance

Question 40

_{PREBYPASS PERIOD - Incision to bypass​} Pts with Heparin resistance have which deficiency?

Answer 40

**Antithrombin III** deficiency

Question 41

_{PREBYPASS PERIOD - Incision to bypass​} What is Antithrombin III?

Answer 41

A serum protease that, when bound to heparin, potentiates its action 1000-fold (100-fold on recording)

Question 42

_{PREBYPASS PERIOD - Incision to bypass​} Pts with Antithrombin III deficiency should be given?

Answer 42

**FFP** administration (contains Antithrombin III) **Antithrombin III concentrate** (Very EXPENSIVE!!!)

Question 43

_{PREBYPASS PERIOD - Incision to bypass​} Pts may also have Heparin-Induced Thrombocytopeina (HIT). When is HIT diagnosed? What's its main characteristic? Which panel confirms the diagnosis of HIT?

Answer 43

HIT is typically diagnozed **5-10 days** *after heparin administration* HIT is characterized by a **30-50% drop** in *platelet count* Diagnosis is confirmed with HIT panel

Question 44

_{PREBYPASS PERIOD - Incision to bypass​} How should pts with confirmed HIT be anticoagulated?

Answer 44

Consider **alternative anticoagulant** (Argatroban, Bivalirudin, Hirudin, Ancrod)

Question 45

_{PREBYPASS PERIOD} Why and when should patients be given antifibrinolytic?

Answer 45

To **prevent** the incidence of **thrombotic complication** Patients should be given an antifibrinolytic either prior to or during the administration of heparin It becomes especially helpful in patients who either refuse blood products (like Jehovah’s witnesses), or Those at high *risk for postoperative bleeding*

Question 46

_{PREBYPASS PERIOD} What makes Amicar and Tranexamic Acid (TXA) popular as antifibrinolytics?

Answer 46

They do not interfere with ACT levels They have a low incidence of allergic reaction

Question 47

_{PREBYPASS PERIOD} What's Aminocaprocic Acid (Amicar) mechanism of action?

Answer 47

**Prevents** the breakdown of **fibrin clots** by inhibititing activation of **plasminogen**

Question 48

_{PREBYPASS PERIOD} How is Aminocaprocic Acid (Amicar) administered?

Answer 48

**50-75 mg/kg** loading dose Followed by 20-25 mg/kg/h OR Standard 5-10 g loading dose prior to Heparin administration, and 5-10 mg dose after Protamine given

Question 49

_{PREBYPASS PERIOD​} What's Tranexamic Acid (TXA) mechanism of action?

Answer 49

Prevents **hemostatic plug dissolution** By blocking the binding of plasminogen and plasmin to fibrin clots

Question 50

_{PREBYPASS PERIOD​} How is Tranexamic Acid (TXA) administered?

Answer 50

**10 mg/kg** Followed by 1 mg/kg/h

Question 51

_{PREBYPASS PERIOD​} The antifibrinolytic Aprotinin was used for redo cardiac surgeries; why is it no longer used?

Answer 51

Was found to **increase mortality** rates and **renal failure**

Question 52

_{PREBYPASS PERIOD} After heparinization, the aortic cannula is placed in the ascending aorta. Why is the aortic cannula placed first?

Answer 52

Provides access for rapid transfusion to systemic circulation is needed

Question 53

_{PREBYPASS PERIOD} After aortic cannulation, why is the SBP or MAP reduced or maintained (SBP at 100mmHG)?

Answer 53

Prevents **aortic dissection** Avoids **spraying**

Question 54

_{PREBYPASS PERIOD} After aortic cannulation, where is the venous cannula placed?

Answer 54

RA appendage (most often)

Question 55

_{PREBYPASS PERIOD} Venous cannulation can produce hemodynamic instability in which two ways?

Answer 55

_First, Blood must be taken from the systemic circulation to “wrap” the machine Volume depletion in the amount of 1.5-2 liters can occur This could lead to **Hypotension** d/t Volume depletion and/or mechanical depression _Secondly, **Arrhythmias** can occur, for which pharmacologic treatment, defibrillation, or immediate initiation of bypass may be required

Question 56

_{PREBYPASS PERIOD} Pharmacologic treatment of A-fib during venous cannulation should be assessed relative to their chances of causing:

Answer 56

**Hypotension**

Question 57

_{PREBYPASS PERIOD} What's the main source of Dysrhythmias noted during venous cannulation?

Answer 57

Atrial ^(mainly)

Question 58

_{PREBYPASS PERIOD} What are treatment options for dysrhythmias noted during venous cannulation?

Answer 58

**Pharmacologic treatment** ^{(Amiodarone, Adenosine, Esmolol, Ca+ channel blocker Verapamil/Diltiazem)} _Direct electrical cardioversion_ **Immediate initiation of CPB**

Question 59

_{PREBYPASS PERIOD - Cannulation Complications} Some complications of cannulation include:

Answer 59

**Malposition** of the aortic cannula **Reversed** cannulation **Obstruction** to venous return Massive **air embolism** management

Question 60

_{PREBYPASS PERIOD - Cannulation Complications} Malposition of arterial (return) cannula could have which effects?

Answer 60

Flow entering the **innominate artery**, or **Jet stream** created which causes **aortic dissection**

Question 61

_{PREBYPASS PERIOD - Cannulation Complications} Reversed cannulation could have which effects?

Answer 61

**Blood drained from aorta** and **infused into vena cava** **Massive gas (air) embolism** * Rare, potentially catastrophic event* * Vigilance!*

Question 62

_{PREBYPASS PERIOD - Cannulation Complications} Obstruction to venous return may be caused by?

Answer 62

Surgical lifting of the heart Kincked or malpositionned cannula Airlock within the venous system

Question 63

_{PREBYPASS PERIOD - Cannulation Complications} Obstruction to venous return may result in?

Answer 63

Decreased venous return Impedence to venous drainage from the head and neck May or may not produce increased CVP _{(especially if the tip of the central line is adjacent to the cannula)}

Question 64

_{PREBYPASS PERIOD - Cannulation Complications} How is the complication of "Massive gas/Air Embolism" managed?

Answer 64

Requires Rapid identification and cordonated response to: **Removing the air,** **Restoring circulation**, and **Protection of the brain** from ischemia

Question 65

_{PREBYPASS PERIOD - Cannulation Complications} Other notable cannulation complications include:

Answer 65

Failure of oxygen supply Pump or oxygenator failure Clotted circuit