Cardiovascular Anesthesia Pt. II (Exam III) Flashcards
When is the highest risk of mortality from a surgery after an MI?
Within the 1st 30 days after the MI
When should an arterial line be placed for cardiac surgery?
Preoperatively (preop area or pre-induction)
What drug is necessary prior to cardiac surgery in the preop area?
Versed
How should an initial reading with the cerebral oximeter be measured?
Baseline measurement at room air
What four factors result in our cerebral oximeter reading?
- MAP
- FiO₂
- Hgb
- EtCO₂
What is the most important thing during sternal incision?
Lungs need to be down
What possible complication can occur doing a redo sternotomy on someone who had previous heart surgery years ago?
Pericardium can be adhered to sternum and at risk of being cut by the saw.
What changes should be made from a first time steronotomy to a redo sternotomy?
2ⁿᵈ Sternotomy needs:
- Blood in room
- Bypass primed and on field
What should be done as the pericardium is opened?
- Assess color of pericardial fluid (should be straw-colored)
- ↓ lung volumes as pericardium is tacked.
Systolic BP must not exceed _______ mmHg as we cannulate.
90 - 100 mmHg
What is the bypass dose of heparin?
3mg/kg
or
300units/kg
What is the ideal body weight dosage of heparin for cardiopulmonary bypass?
Trick question. Heparin for bypass is dosed on actual body weight.
ACT must be greater than ______ to go on bypass.
400
When is ACT drawn after heparin administration?
3 - 5 minutes
What should an ACT be for off-pump heart surgeries?
300 - 350 is acceptable
If a repeated dose of heparin does not achieve an ACT of 400 or greater, what should be considered?
ATIII deficiency (consider giving FFP or ATIII directly)
How often must cardioplegia solution be administered to maintain cardiac arrest?
Every 20 - 30 min
CMRO₂ will decrease __% for every 1°C drop in temperature.
7%
What is the temperature goal in cardiac surgery?
32°C
Where are bypass grafts sewn first? Why is this?
Distally
Done so that warming can begin.
What is our target temperature during re-warming?
35.5 - 37°C
When should postoperative sedation start being considered during a cardiac operation?
During re-warming.
Versed, Precedex, Propofol…
What aortic clamp is used to allow partial flow whilst sewing on proximal grafts?
Partial occluder clamp
What cannot be maintained if a patient is cold coming off bypass?
Stable rhythm
Cold = V-fib.
What joule dosage is used on the internal defibrillator paddles?
20 - 30 joules
What is our BP goal around decannulation time?
90 - 100 sBP
When are antibiotics typically redosed in CV surgery?
Decannulation
Dependent on drug and bypass time.
What should be done prior to restarting the patient on the ventilator after cardiopulmonary bypass?
Alveolar recruitment
What is the dose of protamine for CPB reversal?
1mg/kg
How is protamine best administered?
IV Piggyback
What should be held as the chest is wired shut?
Respirations
What specific type of pump is most often used in adult CPB?
Roller pump
What are the most important characteristics of a centrifugal roller pump?
- Pressure limited
- Higher prime volume
What priming solution is most often used for a CPB pump?
Crystalloid typically
What is the typical priming volume for a CPB pump?
1500 - 2500 mLs
What additive may be included in a CPB circuit dependent on specific patient factors?
- Albumin
- PRBCs
- Electrolytes
- Mannitol
- Heparin
What hematocrit would be expected for a patient on CPB? Why?
Low HCT expected (17 - 25%)
This is due to dilutionary effects from the pump prime.
What two things are used for myocardial protection during cardiac surgery?
- Cold, Hyperkalemic Cardioplegia
- Systemic Hypothermia
Where is cardioplegia administered in:
Antegrade?
Retrograde?
- Antegrade = Aortic root
- Retrograde = Coronary sinus
- On occasion a graft may also be used
What is the most common lung injury due to CPB?
Pump Lung (Acute Lung Injury)
What are the characteristics of pump lung?
- Diffuse congestion & edema
- Hemorrhagic atelectasis
What is the main CNS complication of CPB?
“Pump Head”
- Stroke is also a major risk