Mod3: MINIMALLY INVASIVE CARDIAC PROCEDURES

Question 1

_{MINIMALLY INVASIVE CARDIAC PROCEDURES}

Minimally invasive cardiac procedures are becoming more and more of a mainstay. They are replacing the traditional sternotomy for which pt population?

Answer 1

Pts that are not candidate for open sternotomy

While minimally invasive cardiac procedures haven’t been fully adopted for use in all pt’s populations, they are becoming more and more favorable

Question 2

_{OFF PUMP CABG}

Coronary Artery Bypass Grafting (CABG) has traditional been performed with the use of which machine?

Answer 2

The Cardio Pulmonary Bypass (CPB) machine

Question 3

_{OFF PUMP CABG}

Studies have suggested that the heart function is better preserved if it is managed which way during the operation?

Answer 3

If it is not stopped during the operation

Question 4

_{OFF PUMP CABG}

Which approach to cardiac surgery is also known as the “beating heart” surgery or OBCAB

Answer 4

OFF PUMP CABG

Technique developed as new revolutionary procedure performed without the use of a cardiopulmonary bypass machine

Question 5

_{OFF PUMP CABG}

Advantages:

Answer 5

Reduction in risk of stroke,

^{<em>Although the rate of neuro cognitive dysfunction remains the same</em>}

Less systemic anticoagulation needed

Thought to avoid potential morbidities associated with extracorporeal membrane

Faster recovery and reduced procedural costs

Eliminate risk of aortic manipulation for cannulation and cross-clamping

Question 6

_{OFF PUMP CABG}

Potential morbidities associated with extracorporeal membrane that may be avoided by performing “Off Pump CABG” inlude?

Answer 6

Systemic inflammatory response

Platelet activation

Fibrinolysis

Bleeding

Vasodilatory shock

Question 7

_{OFF-PUMP CABG MORBIDITY AND MORTALITY}

What are disadvantages of “Off-pump CABG”?

Answer 7

More challenging, requiring additional training

Difficulty performing distal anastomoses on the distal part of the beating heart

Motion of coronary artery hampers accurate anastomotic suturing

^{<em>The beating heart causes the coronaries to move, which can impede accurate anastomotic suturing</em>}

Heart must be manipulated and lifted to reach posterior and lateral targets

^{<em>And this can cause a significant left to right ventricular hemodynamic deterioration</em>}

Question 8

_{OFF-PUMP CABG MORBIDITY AND MORTALITY}

How does “Off-pump CABG” affect morbidity and mortality at 1 and 3 year marks

Answer 8

At 1 and 3 year marks, OPCAB showed a reduction in morbidity and mortality

_{Initially, studies that evaluated mortality showed a reduction in death a/w off pump CABGs}

Question 9

_{OFF-PUMP CABG MORBIDITY AND MORTALITY}

Why are higher long term mortality rates (at the At 5 year mark) seen with “Off-pump CABG”?

Answer 9

Reduction in graft patency (Worse graft patency)

Increased risk for repeat revascularization (Less complete revascularization)

Question 10

_{OFF-PUMP CABG MORBIDITY AND MORTALITY}

What does “Repeat revascularization” means?

Answer 10

….

Question 11

_{OPCAB PATIENT SELECTION}

What’s the goal for “Off-pump CABG”?

Answer 11

Complete revascularization

Pts are selected with this goal in mind

Question 12

_{OPCAB PATIENT SELECTION​}

T/F: OPCAB has been choosen for low-risk as well as high-risk pts

Answer 12

True

Question 13

_{OPCAB PATIENT SELECTION​}

What’s an example of a low risk pt for whom OP-CABG can be choosen?

Answer 13

Pt with a single of fewer number of diseased vessels

Question 14

_{OPCAB PATIENT SELECTION​}

What’s are examples of a high-risk pt for whom OP-CABG can be choosen?

Answer 14

Patients with contraindications to conventional CABG

Pts who have plaque in the ascending aorta

Pts with extensive aortic atheromatous or calcific changes

Pts who have comorbidities such as stroke, liver cirrhosis and renal or pulmonary dysfunction

History of stroke

Question 15

_{OPCAB PATIENT SELECTION​}

Why is OP-CABG indicated for pts who have plaque in the ascending aorta, or pts who show extensive aortic atheromatous or calcific changes?

Answer 15

Because conventional CABG precludes them from aortic cross-clamping

Question 16

_{OPCAB PATIENT SELECTION}​

Besides low and high risk groups, for which other categories of pts is OP-CABG indicated?

Answer 16

Patients with isolated proximal LAD CAD/fewer number of diseased vessels

Occasionally patients with LAD and proximal RCA CAD

Pts with No prior cardiac surgery history

Question 17

_{OPCAB PATIENT SELECTION}

Other considerations for OP-CABG include?

Answer 17

Surgeon expertise

Extent of atherosclerosis of ascending aorta

Extent of technically challenging anatomy

Question 18

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS}

What’s the most popular alternative to sternotomy that utilizes a limited thoracotomy incision?

Answer 18

Minimally invasive Direct Coronary Artery Bypass

Also known as a MIDCAB

MIDCAB is a minimally invasive approach to conventional CABG​

Question 19

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS}

MIDCAB can be performed two ways

Answer 19

Can be performed with

Elimination of CBP and cardioplegia, or

Elimination of cardioplegia only

_{For the purpose of this lecture, we will focus on the option that involves Elimination of CBP and cardioplegia}

_{So the MICAB will be very similar to “off-pump CABG”}

Question 20

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS}

Why is the A left anterior thoracotomy is used for the MIDCAB procedure?

Answer 20

It allows for direct access to the IMA for harvesting and grafting to the LAD

Question 21

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS}

The MIDCABs can be categorized into three groups; that are?

Answer 21

Direct access MIDCAB

Thoracoscopic MIDCAB

Robotic MIDCAB

Question 22

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS}

Why are Thoracoscopic MIDCABs and Robotic MIDCAB also known as endoscopic MIDCABs?

Answer 22

Because they use a video-assisted device

_{Many facilities that perform MIDCABs use the Thoracoscopic or Robotic approaches}

Question 23

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS}

The standard approach MIDCAB that uses an anterior thoracotomy is also known as

Answer 23

Direct access MIDCAB

Question 24

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS}

Why are many Centers shying away from Direct access MIDCAB?

Answer 24

Visualization of the LIMA is difficult and

The rib-spreading required for visualization is associated with postoperative thoracotomy pain

_{<em>Many facilities that perform MIDCABs use the Thoracoscopic or Robotic approaches</em>}

Question 25

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS​} Which MIDCAB approach uses small thoracoscopic ports for incision sites

Answer 25

Thoracoscopic MIDCAB It uses the Non-rib-spreading technique

Question 26

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS​} What are benefits of the Non-rib-spreading technique used in Thoracoscopic MIDCABs?

Answer 26

Non-rib-spreading technique is associated with Very good flow down the LIMA, and High LIMA-LAD graft patency

Question 27

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS​} Which MIDCAB approach uses thoracoscopic ports, but also utilizes a robot to harvest the LIMA

Answer 27

Robotic MIDCAB

Question 28

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS​} What are benefits of Robotic MIDCAB

Answer 28

Excellent visualization and maneuverability of instruments inside the thoracic cavity Good quality of harvested LIMA Good LIMA to LAD anastamosis

Question 29

_{MINIMALLY INVASIVE DIRECT CORONARY ARTERY BYPASS​} Which MICAB approach requires deflation of the lung on the operative side?

Answer 29

Robotic MIDCAB

Question 30

_{MIDCAB ADVANTAGES} What are advantges of MIDCAB's small thoracic incisions, especially the non-rib-spreading ones

Answer 30

Eliminate the potential morbidity a/w CABG and the median sternotomy Results in potential for more rapid and complete recovery

Question 31

_{MIDCAB ADVANTAGES} For which cardiovascular procedures do utilizing MIDCABs offers advantages?

Answer 31

Repair congenital defects like ASDs and VSDs Aortic valve replacements MV repairs Multivalves procedures

Question 32

_{MIDCAB ADVANTAGES} Overall, what are advantages of MIDCAB procedures?

Answer 32

Lower Infection rate Less Cost (25% less than conventional CABG surgery) Shorter length of stay Faster Recovery (reduced risk of complications; can return to normal activity within 2 weeks) Less Bleeding and Blood trauma (the damage to the blood from the CPB machine is avoided; smaller incision-less blood loss) Available to more patients (poor candidates for conventional CPB may be candidates for less invasive techniques) Applicable to a broad range of complex cardiac procedures

Question 33

_{PLACEMENT OF INCISION DURING MINIMALLY INVASIVE HEART VALVE SURGERY} Where is the incision placed for minimally invasive aortic valve surgery?

Answer 33

Below the right clavicle, and Above the right nipple

Question 34

_{PLACEMENT OF INCISION DURING MINIMALLY INVASIVE HEART VALVE SURGERY} Where is the incision placed for minimally invasive mitral and intracupsid valve surgery?

Answer 34

Below the right nipple

Question 35

_{MIDCAB DISADVANTAGES} What percent reduction in mortality rates was oberved when MIDCABs were performed by more experienced surgeons?

Answer 35

**5% reduction in mortality rates** _{A meta-analysis documented a significant surgeon volume relationship with a 5% reduction in mortality rates in surgeons who perform high volumes of these procedures} MIDCABs Require experienced surgeon for best outcomes

Question 36

_{MIDCAB DISADVANTAGES} What's a disadvantage of the small MIDCAB incisions?

Answer 36

Limited access to specific regions of the heart Poor access to distal RCA and PDA Make complete re vascularization difficult, especially when it comes to identifying and bypassing smaller myocardial vessels

Question 37

_{MIDCAB DISADVANTAGES} Why is constructing inflows to secondary grafts with MIDCABs procedures?

Answer 37

Proximal anastomosis to the ascending aorta more challenging

Question 38

_{MIDCAB DISADVANTAGES} What would will make Robotic surgery procedures technically difficult?

Answer 38

Any anatomical issues that hinder port placement or limit robotic arm movement Prior thoracic surgery Chest radiation Thoracic trauma

Question 39

_{MIDCAB DISADVANTAGES} T/F: Higher blood transfusion rates associated with robotic cardiac surgery than with other robotic procedures

Answer 39

True

Question 40

_{MIDCAB PATIENT SELECTION} Why is appropriate patient selection is important?

Answer 40

To reduce the risk of perioperative complications

Question 41

_{MIDCAB PATIENT SELECTION} Robotic or Thoracoscopic (Endoscopic) approaches may not suitable for smaller pts; why?

Answer 41

Insufficient intrathoracic space for CO2 insufflation

Question 42

_{MIDCAB PATIENT SELECTION} T/F: Except for difficulty with smaller pts and endoscopic procedures, the pt selection for MIDCAB is Similar to the patient selection for Off pump CABG

Answer 42

True

Question 43

_{MIDCAB PATIENT SELECTION} Except for difficulty with smaller pts and endoscopic procedures, the pt selection for MIDCAB is Similar to the patient selection for Off pump CABG and include?

Answer 43

Patients who are considered low risk with anterior lesions specifically of the LAD Those with fewer number of diseased vessels High risk patients or patients with contraindications for bypass surgery Or if they are scheduled to have a sternotomy for another cardiac procedure

Question 44

_{MIDCAB PATIENT SELECTION} High risk patients or patients with contraindications for bypass surgery include

Answer 44

Extensive ascending aorta atheromatous or calcific changes Patients who require reoperation, but in whom a sternotomy or CPB is contraindicated/higher risk Future sternotomy for other cardiac procedure

Question 45

_{MIDCAB PATIENT SELECTION} Patients who require reoperation, but in whom a sternotomy or CPB is contraindicated/higher risk include:

Answer 45

Patients who require redo-sternotomy, but have cardiac sutures adhering to the posterior sternum Previous sternal infection Mediastinal radiation

Question 46

_{OPCAB and MIDCAB SURGICAL CONSIDERATIONS} Describe vessel harvesting, incision and anastamosis with the MIDCAB procedure (Anterior thoracotomy approach)

Answer 46

an anterior thoracotomy is made and the internal mammary artery (Left or Right) is harvested from the thoracic wall For anastamosis to the LAD

Question 47

_{OPCAB and MIDCAB SURGICAL CONSIDERATIONS} Describe vessel harvesting, incision and anastamosis with the OPCAB procedure

Answer 47

The conduit vessels, either the saphenous vein, or radial arteries, are harvested in the same fashion that they would be for a traditional CABG A sternal incision is then made The pericardium is opened and tacked to the edges of the mediastinum ^{This raises the heart out of the chest wall} Sternal retractors placed ^{Allow for the placement of surface pressure devices on the myocardium called stabilizers}

Question 48

_{OPCAB and MIDCAB SURGICAL CONSIDERATIONS} What results when the pericardium is opened and tacked to the edges of the mediastinum?

Answer 48

This raises the heart out of the chest wall

Question 49

_{OPCAB and MIDCAB SURGICAL CONSIDERATIONS} For OP-CAB what's another name for the surface pressure devices on that are placed on the myocardium after Sternal retractors are placed?

Answer 49

Stabilizers

Question 50

_{OPCAB and MIDCAB SURGICAL CONSIDERATIONS} Where are Stabilizers placed? What's their function?

Answer 50

Placed on epicardium over planned site of arteriotomy Stabilize the myocardium to reduce movement of the site of anastamosis Example of stabilizer: ***Octopus Stabilizer***

Question 51

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} For both OPCAB and MIDCAB, why must the cardiopulmonary bypass machine is on standby?

Answer 51

In the event that emergency bypass is needed A perfusionist must be in attendance

Question 52

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} T/F: Double lumen tube, bronchial blocker, or endobronchial tube will be inserted for MIDCAB procedures

Answer 52

**True** Why?...

Question 53

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Why should External defibrillator pads should be placed for both procedures; especially for MIDCAB procedures?

Answer 53

Because the surgeon will not have direct access to the heart to place internal pads in the event of V-fib

Question 54

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} What monitors must be available for both OP-CAB and MIDCAB procedures?

Answer 54

*All the traditional monitors for traditional cardiac surgery:* 5-lead EKG - Pulse oximetry Temperature monitoring - Radial arterial line Central venous catheter/ PAC ? Foley Catheter - TEE

Question 55

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} What are the anesthetic goal for off pump cases?

Answer 55

Ensure that there is maximum cardiac protection Stable hemodynamics and cardiac rhythm Promote *fast-track anesthesia*

Question 56

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS​} What does fast-track anesthesia means? What's required to achieve it?

Answer 56

Extubation within 0-6 hours after ICU admission Adequate postoperative analgesia is required to achieve fast-track anesthesia

Question 57

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS}​ How can anesthesia be delivered for OPCAB and MIDCAB?

Answer 57

General anesthesia (GA) with opioids and inhalational agents or TIVA Combined GA with controlled ventilation and neuroaxial blockade using high thoracic epidural

Question 58

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} General anesthesia with the use of opioids and inhalational agents offer the advantage of

Answer 58

Anesthetic ischemic preconditioning

Question 59

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Why must careful consideration be taken with the use of neuromuscular blocking agents during General anesthesia

Answer 59

May interfere with the goal is fast-tracking Roc and Nimbex are recommended

Question 60

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Remifentanil a good option for General anesthesia (GA) with opioids and inhalational agents or TIVA, but

Answer 60

must ensure adequate analgesia prior to discontinuation

Question 61

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} What are the benefits of combined GA with controlled ventilation and neuroaxial blockade using *high thoracic epidurals?*

Answer 61

Improved analgesia, pulmonary outcomes, and reduction in M&M They ensure hemodynamic stability and decrease myocardial O2 demands by attenuating the neuro hormonal response

Question 62

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} When must thoracic epidural be inserted to reduce the risk of developing epidural hematomas?

Answer 62

The day before surgery or 1 hour prior to Heparin administration (minimally) *Important to assess patient’s preoperative anticoagulation status*

Question 63

_{OP-CAB HEMODYNAMIC CONSIDERATIONS} Hemodynamic instability during off pump cabgs due to

Answer 63

Myocardial ischemia Mobilization and stabilization of heart for OPCAB *^{Pushing and tilting the heart for exposure of anastomosis sites}*

Question 64

_{OP-CAB HEMODYNAMIC CONSIDERATIONS} Mobilization and stabilization of heart for OPCAB necessitates pushing and tilting the heart for exposure of anastomosis sites. What are the negative consequences of this?

Answer 64

Reduces stroke volume and ABP Increases CVP and RVEDP *^{which leads to decreased RVOT flow}* Distortion of mitral and tricuspid annuli *^{which can either cause or worsen regurgitation through those valves}*

Question 65

_{OP-CAB HEMODYNAMIC CONSIDERATIONS} Mobilization and stabilization of heart for OPCAB necessitates pushing and tilting the heart for exposure of anastomosis sites. What's the treatment for the negative effects associated with this?

Answer 65

Inotropes and vasopressors Adequate, but cautious fluid management Fluid loading prior to stabilizing device being placed Trendelenburg

Question 66

_{OP-CAB HEMODYNAMIC CONSIDERATIONS} Mobilization and stabilization of heart for OPCAB necessitates pushing and tilting the heart for exposure of anastomosis sites. This is could have negative effects including hypotension. What should you do If hypotension persists despite the treatment?

Answer 66

Myocardial ischemia should be suspected and evaluated by monitoring the EKG and the TEE Consider conversion to cardiopulmonary bypass if hypotension unresponsive

Question 67

_{OP-CAB HEMODYNAMIC CONSIDERATIONS} Mobilization and stabilization of heart for OPCAB necessitates pushing and tilting the heart for exposure of anastomosis sites. This could have negative effects that are typically not seen with MIDCAB. Why not?

Answer 67

Not much cardiac manipulation

Question 68

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Hemodynamic instability less likely - why?

Answer 68

Reserved for single vessel disease of the LAD Procedure done on anterior side of the heart Not much heart manipulation

Question 69

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Why is there a potential for ventilation/perfusion issues in endoscopic MIDCAB procedures that utilize a robot?

Answer 69

One lung ventilation required with double lumen ETT or bronchial blocker May result in oxygen desaturations

Question 70

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Why do endoscopic MIDCAB procedures that utilize a robot result in oxygen desaturations from One-lung ventilation?

Answer 70

The non ventilated lung continues to be perfused despite it not taking part in gas exchange Subsequently, these pts develop a "***right to left intrapulmonary shunt"*** Deoxygenated blood from non-inflated lung mixing with oxygenated blood from ventilated lung ***Hypoxic Pulmonary Vasoconstriction (HPV)*** attempts to correct by reducing blood flow to non-ventilated lung However we do know that HPV can be attenuated by anesthetic gasses a vasopressors There is also a risk for barotrauma!!!

Question 71

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Which gas is used for insufflation of the thoracic cavity (left hemithorax)? Why?

Answer 71

**CO2** This allows for exposure of the heart and great vessels as well as preventing smoke formation during cautery usage

Question 72

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Which CO2 levels are adequate to visualize cardiac structures?

Answer 72

5-10 mmHg

Question 73

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} What's a possible negative effect of CO2 levels of 5-10 mmHg

Answer 73

Increased intrathoracic pressure Decreased venous return Which can impair systemic BP and worsen hypoxia

Question 74

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Negative effects () of 5-10 mmHg of CO2 used to insufflation thoracic cavity will be more pronounced in patients with

Answer 74

Reduced ventricular function Increased risk for hypercapnia

Question 75

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Patient positioning; *why*?

Answer 75

Supine position with roll underneath left scapula ## Footnote * Facilates surgical exposure* * Provides adequate room for the robot and the robotic arm to move freely*

Question 76

_{MIDCAB HEMODYNAMIC CONSIDERATIONS} Why is it important to note the position of the left arm?

Answer 76

The left arm must be positionned posteriorly at the pt side for adequate exposure However, caution must also be used to watch for brachial plexus injuries This becomes especially important in longer procedures where the pt is in this position for a long period of time

Question 77

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Which technique is used by many surgeons to create the anastomosis in a blood-less field?

Answer 77

Temporary occlusion of the target coronary artery Surgeons will temporarily occlude the target coronary artery to create a blood-less field for anastomosis of the grafts

Question 78

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Heparin should be administered prior to the occlusion of the target coronary artery. At which dose and for ACT target?

Answer 78

150-200 units/kg, target ACT \>300 s

Question 79

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} During Temporary occlusion of the target coronary artery, maintain HR and MAP of:

Answer 79

HR 70-80 bpm, MAP \>70 mmHg This is to allow for adequate coronary perfusion

Question 80

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} The patient’s response to occlusion depends on

Answer 80

Degree of collateral circulation

Question 81

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Why is Temporary occlusion of the target coronary artery tolerated poorly in Moderate stenosis?

Answer 81

Poor collateral circulation The stenotic lesion has not been present for long enough to develop adequate collateral circulation

Question 82

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Why is Temporary occlusion of the target coronary artery tolerated better in severe stenosis?

Answer 82

More well developed collateral circulation

Question 83

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Prior to occlusion, the surgeon may temporarily occlude the coronary artery and then re-perfuses it prior to making the anastomosis. What is this technique called?

Answer 83

**Ischemic preconditioning** The surgeon may do this a couple of times to preconditionne the heart to be able to tolerate longer period of ischemia that would be required to make the final anatamosis

Question 84

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} What's the purpose of Ischemic preconditioning?

Answer 84

To enhance myocardial performance to decrease ischemic damage during a subsequent prolonged period of ischemia

Question 85

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Which drugs can also be increased for preconditioning?

Answer 85

**Inhalational agents** Use of inhalational agents =\> anesthetic preconditioning

Question 86

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} When do ischemic changes that occur on the EKG tend to disappear?

Answer 86

After reperfusion Ischemic changes disappear after coronary re-perfused

Question 87

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} The ischemic changes that occur on the EKG tend to disappear after reperfusion. So why would the EKG sometimes show T-wave inversion, or the TEE may show regional wall abnormality?

Answer 87

This is Secondary to ***myocardial stunning*** and ***reperfusion injury***

Question 88

OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS Which Eeectrolytes should be closely monitored postop? why?

Answer 88

**Potassium** or **Magnesium** To prevent ***reperfusion arrythmias***

Question 89

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS​} How should arrythmias be treated?

Answer 89

Arrythmias should be treated promptly Use of a pacemaker should be employed if necessary

Question 90

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} Neuromuscular blockade reversal will depend on

Answer 90

Stability of the patient and How soon extubation is anticipated

Question 91

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} What's required for extubation to take place?

Answer 91

Hemodynamic stability and Warm normovolemic patient who is alert and pain free

Question 92

_{OPCAB and MIDCAB ANESTHETIC CONSIDERATIONS} What's the special consideration for using Protamine for heparin reversal?

Answer 92

Consider on a patient by patient basis Full versus partial reversal