Term
| What is the goal of fast-track CABG? |
|
Definition
| To wean the patient off the vent in 4 hours (some locations use 6 hours) |
|
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Term
| What are the criteria for being able to fast-track a CABG patient? |
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Definition
1) Surgeon technically satisfied with procedure.
2) If difficult anticipated or unanticipated intubation patient must:
a. have no evidence of bleeding, swelling or other airway trauma.
b. arrive in the CVICU no later than 3pm.
3) Patient without evidence of poor oxygenation or ventilation.
4) Patient on minimal hemodynamic support.
5) Patient without significant hemodynamically compromising arrhythmias.
6) Patient without significant bleeding problems. |
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Term
| What drugs should be limited if fast-tracking a patient? |
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Definition
Versed: 0.5 – 1.0 mg/kg (or less!)
Fentanyl: < 20 cc total |
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Term
| Can propofol be used with fast-track patients? |
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Definition
• Use some propofol with induction (0.5 – 1.0 mg/kg). May use etomidate.
• Use small doses of Propofol and/or agent during periods of increased stimulation and increased BP
• Take patient to ICU on Propofol drip. Propofol allows use of less narcotic and less benzodiazepines and because it is short-acting doesn’t prevent a quick wean. |
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Term
| What is an alternative to a propofol gtt for fast-track patients? |
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Definition
| An alternative is Dexmedetomidine. |
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Term
| Can local anesthesia be used for a CABG patient? |
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Definition
Some institutions use:
-a parasternal block
-LA at the chest tube sites to reduce post op narcotic requirements. |
|
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Term
| What requirements must a fast-track patient meet prior to vent weaning? |
|
Definition
-the patient must be warm,
-hemodynamically stable and
-without heavy chest tube drainage. |
|
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Term
| What is the defining characteristic of VHD (valvular heart disease)? |
|
Definition
| Abnormalities of ventricular loading. |
|
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Term
| How do we determine ventricular function of VHD patients? |
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Definition
| The status of the ventricular function is determined by the progression of the P and V overload. |
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Term
| What do we need to know when giving anesthesia for a patient with VHD? |
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Definition
Based on the patient’s underlying valvular disorder, Know goals for:
-HR and rhythm,
-SVR,
-preload,
-contractility |
|
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Term
| Is a valve repair/replacement faster than a CABG? |
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Definition
| These procedures, if done exclusively without a CABG, tend to be somewhat faster procedures (if uncomplicated, then <4hours). |
|
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Term
| Why do we use the TEE for in a valve replacement? |
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Definition
TEE can be used to check for
-air embolism
-regurgitant flow,
-valve sizing,
-evaluation of the ventricle. |
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Term
| What will be done at the end of a valvular surgery? |
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Definition
| Will use de-airing techniques at end of case. |
|
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Term
| Why does a post-op CABG usually return to the OR? |
|
Definition
Usually for generalized bleeding.
-may find a bleeder
-more often it is due to coagulopathy |
|
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Term
| How should a "bring back" patient's airway be managed? |
|
Definition
|
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Term
| What is our primary concern with vascular access for a "bring back" patient? |
|
Definition
Untangle lines and
***figure out where you can give drugs & blood |
|
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Term
| What lab should be sent for a "bring back" patient? |
|
Definition
|
|
Term
| What is a typical anesthetic for a "bring back" patient? |
|
Definition
-pavulon,
-versed
-fentanyl as BP tolerates
-(minimal forane until BP is OK) . |
|
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Term
| What special piece of equipment should be available for a "bring back" patient? |
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Definition
| May be placed on a IABP at the end of the procedure. |
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Term
| What are the advantages of a CABG on pump? |
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Definition
-Allows full access to heart: visually & surgically
-Bloodless operating field
-Easier to work on still heart
-Multiple grafts are possible + valves. |
|
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Term
| What are the disadvantages of a CABG on pump? |
|
Definition
-Risks using bypass machine, particularly systemic imflammatory response syndrome (SIRS)
-Large incision / broken breastbone/ leg incision.
-Large scar |
|
|
Term
|
Definition
systemic imflammatory response syndrome (SIRS) which is the activation of chemical mediators released as the
blood comes into contact with the CPB circuit. |
|
|
Term
| What are the advantages of CABG off pump? |
|
Definition
-Allows full access to heart: visually & surgically
-Avoids complications from using bypass such as organ damage
-Quicker recover, shorter stay
-No cross clamping of aorta |
|
|
Term
| What are the disadvantages of CABG off pump? |
|
Definition
-Beating heart surgery - more challenging
-Large incision/broken breastbone/leg incision.
-Large scar |
|
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Term
| What are the advantages of a MIDCAB? |
|
Definition
-Less invasive - scar is smaller
-Breastbone is intact
-Avoids complications from using bypass such as organ damage
-Quicker recover, shorter stay |
|
|
Term
| What are the disadvantages of a MIDCAB? |
|
Definition
-Beating heart surgery - more challenging
-Restricted view
-Exceptionally challenging for the anesthesia team |
|
|
Term
| What are the major complications of using the pump? |
|
Definition
-Embolism from X-clamoing aorta
-SIRS
-Transfusion
-Pain from sternotomy
-neuropsychiatric changes |
|
|
Term
| How long does cognitive impairment last after CPB? |
|
Definition
-The impairment was not temporary, as many doctors have claimed (or at least hoped).
-The decrease in cognitive capacity persisted for 5 years. |
|
|
Term
| Are the neuro changes from CPB related to age? |
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Definition
| The mental impairment was not due to the patients' age (which averaged 61). |
|
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Term
| What is the suspected cause of pump head? |
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Definition
| The most common speculation is that the mental changes are due to the showering of the brain with microemboli related to the use CPB |
|
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Term
| What is one way to reduce post CABG depression? |
|
Definition
| use of a high thoracic epidural |
|
|
Term
| What is ischemic preconditioning? |
|
Definition
| A reduction in ischemia or necrosis during off pump procedures |
|
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Term
| What are the techniques from ischemic preconditioning? |
|
Definition
-Surgically: brief occlusion of the artery (5 min) followed by reperfusion before performing anastomosis.
-Anesthesia: giving 1 MAC or end-tidal forane prior to the anastomosis. (make sure preload is adequate; may have to give pressors) |
|
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Term
| What is the best way to avoid hemodynamic instability when doing off-pump CABG? |
|
Definition
|
|
Term
| What should be ready and in the room when doing an off-pump CABG? |
|
Definition
| All medications and equipment needed for CPB. |
|
|
Term
| What are some common intra-operative complication to off-pump CABG? |
|
Definition
-decreased cardiac output
-decreased mean arterial pressures
-dysrhythmias |
|
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Term
| How are the hemodynamic swings during off-pump CABG treated? |
|
Definition
-Increase IV fluids
-Titrate NTG and Phenylephrine
-RBC’s if needed
-Often needs phenylephrine gtt to maintain BP to supply blood to collateral vessels when the heart is positioned for grafting |
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Term
| What might need to be done with a Swan Ganz catheter during off-pump CABG? |
|
Definition
| It may need to be moved or removed since it can get in the way of the surgeon |
|
|
Term
| How cold should a patient be during off-pump CABG? |
|
Definition
|
|
Term
| When is Minimally Invasive Direct Coronary Artery Bypass (MIDCAB) indicated? |
|
Definition
-When the exact position of the affected coronary artery is known
-Usually, when only a single graft is required
-It may be employed for very high risk patients in specialized heart centers |
|
|
Term
| What is the most common vessel exchange during a MIDCAB? |
|
Definition
|
|
Term
| Is CPB used during MIDCAB? |
|
Definition
| Often no bypass machine is used (OPCAB), however it can be used when necessary (therefore, a MIDCAB can be done with or without CPB). |
|
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Term
| How is the actual bypass grafting procedure different on a MIDCAB than typical CABG? |
|
Definition
The actual bypass procedure on the arteries is the same as the normal CABG.
However, this is a more challenging procedure as the heart is still beating and there is blood present in the operating field (the heart is still pumping blood).
The length of the incision means there is less room for the surgeon to work. |
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Term
| What are the advantages of a MIDCAB over a typical CABG? |
|
Definition
•a small incision
•no sternotomy
•faster recovery and shorter length of stay
•grafting the LIMA to the LAD via a small left para-sternal (thoracotomy)
incision |
|
|
Term
| What is unique about induction prior to a MIDCAB? |
|
Definition
|
|
Term
| Why is a DLT used for MIDCAB? |
|
Definition
| This is to allows maintenance of ventilation in the right lung while the left lung is deflated to enable better visibility of the left internal mammary artery (LIMA). |
|
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Term
| How is CPB used during a MIDCAB? |
|
Definition
-No sternotomy (thoracic approach)
-CPB is achieved via the integrated system of catheters and cannulae that are inserted into:
the groin (a femoral artery catheter = arterial inflow catheter / femoral vein = venous outflow catheter ) and neck and advanced until they reach the heart. |
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Term
| How do the catheters stay in the Aorta during a MIDCAB? |
|
Definition
| Their location in the ascending aorta is maintained with balloons attached to the catheters. |
|
|
Term
| How are catheter positions confirmed during a MIDCAB? |
|
Definition
-The advancement and positioning of the catheters in the heart are monitored using fluoroscopy and transoesophageal echocardiography.
-This monitoring is essential throughout the entire case for both correct placement of all lines and maintenance of their position. |
|
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Term
| What can happen during cannulation of a MIDCAB? |
|
Definition
| There is a potential for the endoaortic clamp to slip and occlude the arteries leading off the aortic arch, blocking blood flow to the rest of the body including the brain, causing right sided damage if not detected. |
|
|
Term
| How would a blockage from the aortic clamp present itself? |
|
Definition
| This would be indicated by a sudden drop in pressure. |
|
|
Term
| How is the CRNA monitoring for migration of the aortic clamp during a MIDCAB? |
|
Definition
-If a transcranial doppler is not used in assessing migration of the endoaortic clamp then bilateral radial artery monitoring is used for the assessment.
-Close monitoring of ECG and aortic root pressures and myocardial temperature are maintained, throughout the procedure. |
|
|
Term
| How is cardioplegia delivered to the heart during MIDCAB? |
|
Definition
| -ANtegrade via coronary arteries |
|
|
Term
| Why aren't the coronary arteries a part of the systemic circulation? |
|
Definition
| They are separated from the systemic circulation by the ascending aortic arch balloon |
|
|
Term
| How is the left ventricle vented during MIDCAB? |
|
Definition
| A catheter is advanced from the internal jugular vein into the pulmonary artery for venting the left ventricle |
|
|
Term
| How is the heart bypassed during MIDCAB? |
|
Definition
| The patient is placed on fem-fem bypass and cardioplegia established |
|
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Term
| What happens at the end of a MIDCAB? |
|
Definition
-The patient is re-warmed,
-Fem-fem bypass is weaned
-Pleural and pericardial drains are inserted.
-The aforementioned catheters and cannulae are removed. -The patient is extubated and re-intubated with a single lumen tube, with the future potential of being extubated on the table |
|
|
Term
| How should the CRNA prepare for V-fib/V-Tach durin MIDCAB? |
|
Definition
-Have CPB ready
-Assure that Defib pads are placed |
|
|
Term
| Where should the A-line be placed during a MIDCAB? |
|
Definition
| Bilateral arterial lines are inserted if the radial artery is not required for grafting. |
|
|
Term
| How is the aorta clamped during a MIDCAB? |
|
Definition
It isn't: There is no clamp on the aorta, just a balloon. A coronary sinus balloon is
also floated |
|
|
Term
| What must be given prior to insertion of coronary sinus balloon during a MIDCAB? |
|
Definition
| the pt must be heparinized. |
|
|
Term
| What is done with the coronary sinus balloon during a MIDCAB? |
|
Definition
| The balloon is inflated 0.1 ml at a time while the RV waveform is monitored (to a total of .25 ml). The amount of fluid required to fill the balloon is documented and noted. |
|
|
Term
| How is the patient positioned during a MIDCAB? |
|
Definition
| Often the left arm is positioned beside the body and the right arm is suspended by a sling. |
|
|
Term
|
Definition
| Transcatheter Aortic Valve Insertion (TAVI) is used to repair the aortic valve without sternotomy or CPB. The new valve is threaded through either the venous or arterial system. |
|
|
Term
| What is the most problematic part of a TAVI? |
|
Definition
Valvuloplasty:
-Patient will need to be paced
-Arrhythmias are common |
|
|
Term
| What is Deep Hypothermic Circulatory Arrest? |
|
Definition
| Full cessation of perfusion following CPB and reduction of core body temperature to 15 to 20 degrees Celsius. |
|
|
Term
| WHat is the advantage of Deep Hypothermic Circulatory Arrest? |
|
Definition
| Provides a suitable surgical field while reducing the risk of ischemia to vital organs, particularly the brain |
|
|
Term
| What are some of the adverse effects of hypothermia? |
|
Definition
• Dysrhythmias due to potassium loss
• Increased plasma viscosity and vasoconstriction, affecting microcirculation
• Impaired coagulation and decreased platelets
• Reduced GFR
• Metabolic Acidosis
• Hyperglycemia - Impaired glucose metabolism
• Pharmacodynamic and pharmacokinetic changes
• Cerebral vasoconstriction on cooling |
|
|
Term
| How long does it take for cerebral ischemia to set in when a patient is normothermic? |
|
Definition
| At 37 C, cerebral ischemia begins in 4 minutes→cardiac arrest |
|
|
Term
| How does CMRO2 change with temperature? |
|
Definition
| Cerebral metabolism decreases 6-7% for each 1 degree C decrease |
|
|
Term
| What is the appropriate length of time for Deep Hypothermic Circulatory Arrest? |
|
Definition
| Studies vary on acceptable times (20-40 minutes), less is always more |
|
|
Term
| What is the goal Hct during Deep Hypothermic Circulatory Arrest? |
|
Definition
-Hemodilution to goal of Hct of 20%--decreased plasma viscosity improves microcirculation
-Avoid a HCT of <10%
o Decreases O2 carrying
o Tissue ischemia |
|
|
Term
| What medications should be given prior to Deep Hypothermic Circulatory Arrest? |
|
Definition
•Anticoagulate with heparin before CPB to a ACT of >480 •Re-dose NDMR. Avoid all movement and shivering
•Propofol, Etomidate, or Thiopental immediately prior to CHCA to decrease CMRO2 and CBF
•Steroids 6-8 hours before DHCA
- Thought to decrease the release of inflammatory cytokines and prevent lysosome breakdown |
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