Cardiac Anesthesia Flashcards
1
Q
What should be included in the preop evaluation of a cardiac patient?
A
- Severity of disease/hemodynamic status
- degree of impairment of contractility
- development of compensatory mechanisms
- exercise tolerance
- Hx of CHF or MI-ST segment changes
- Angina
- dysrhythmias
- compensatory increase in sympathetic nervous outflow
- HR, anxiety, diaphoresis
- Hx of previous surgery
2
Q
Which labs should be included in the pre-op of a cardiac patient?
A
- CBC
- electrolytes
- cardiac enzymes
- serum creatinine
- coagulation profile
- type and cross
- MUST have PRBCs available
3
Q
What changes will you see in lab values after an acute MI?
(graph)
A
- Peak A- early realease of myglobin or CK-MB (Creatinine Kinase with myocardial band) isoforms after AMI
- Peak B- cardiac troponin after AMI
- can be used to determine how much cardiac cell death occured from the MI
- Peak C- CK-MB after AMI
- Peak D- cardiac troponin after unstable angina
4
Q
What is the preferred biomarker for myocardial damage?
Why?
A
- Cardiac troponin
- absolute myocardial tissue specificity (CK can be elevated for other reasons like diet, etc.)
- high sensitivity
5
Q
What other cardiac tests can be done?
A
- Catheterization can tell you:
- LVEDP
- EF
- CI
- Echo can show you:
- EF
- wall motion abnormalities
- CXR can show:
- Cardiomegaly
- pulmonary vascular congestion, edema, effusion
- Angiography
- EKG can show:
- ischemia/infarct
6
Q
What daily medications should be taken up until the operative day?
A
- antiarrhythmics
- Ca+ channel blockers
- B blockers
- nitrates
7
Q
What monitors would you use during a cardiac surgery?
A
- Pulse Ox
- TEE
- EKG- leads V and II
- Temp
- ABG- usually radial, sometimes femoral
- CVP- mandatory for infusion of drugs
- PA catheter
- pts with severe LV dysfunction
- pts with profound pulmonary HTN
8
Q
TEE:
Frequency?
What can it determine?
A
- Intermittent pulses with a frequency of 2.5-7.5 MHz
- Can determine:
- preload
- hypotension
- CO
- LV filling pressures
- LV contractility
- LV afterload
- ischemia, emboli, valvular pathology
- assessment of surgical repairs
9
Q
How do you set up the OR for a cardiac case?
A
- Pacemaker
- Drips (most common):
- NTG/ NTP
- epinephrine/Norepi
- phenylephrine/ephedrine
- dopamine/dobutamine
- antiarrhythmics (esmolol, lidocaine, mag, amiodarone)
- Heparin and coagulation monitoring capability (ACT, TEG)
- emergency drugs
- PRBC available in OR
10
Q
What are the doses for an opioid anesthetic?
What muscle relaxant would be chosen and why?
A
- Fentanyl 50-100mcg/kg
- Sufentanyl 10-20 mcg/kg
- Pancuronium- b/c opioids decrease HR and pancuronium brings it back up
- *today pts are still given large opioid doses, but are induced with etomidate
- **Will get chest rigidity with these large narcotic doses, pre-treat with vecuronium
11
Q
What are the risks associated with administration of vasoconstrictors?
A
- can cause further vasospasm in vasospastic-prone areas of the heart
12
Q
What happens during the incision to bypass period of the surgery?
A
- Intense surgical simuli
- Hypertension
- deepen anesthetic, NTG/NTP
- handling of the heart by the surgeon
- can cause hyper or hypotension and arrhythmias
- communication is very important
- bleeding can be significant
- identifying and localizing inschemia
- drop the lungs for sternotomy
- arterial and saphenous veins are harvested
13
Q
What happens immediately before bypass?
A
- heparinization
- binds to antithrombin III and potentiates its natural anticoagulant properties
- 200-300 units/kg- peaks in 2 minutes
- Check ACT (nml is <130 (70-110)
- ACT of 350-500 is accteptable
- Administer heparin through CVP or directly into RA
- Effects of Heparin:
- SVR and BP decreasy by 10-20%
14
Q
What are some “special circumstances” to keep in mind regarding the heparin administration.
A
- Pt may have antithrombin deficiency
- pt may be on long term heparin therapy
- excessive hemodilution
- heparin-induced thrombocytopenia, antibdy mediated
- NTG- heparin doesnt work properly if pt takes NTG frequently
- **check the ACT 3-5 min after administration. If it is not increased, either give more heparin, or give FFP or thrombate III so the heparin has something to bind to.
15
Q
What happens immediately before bypass?
A
- **Cannulation of the aorta (arterial) and RA (venous)
- Must drop the pts BP for aortic cannulation (to avoid rupture of the aorta)
- BP might drop and /or arrhythmias can occur while placing venous cannula
- the perfusionist can give fluids via the arterial line
- *cannulation of the coronary sinus for retrograde cardioplegia
- can have similar effects (decrease in BP)
- ,medicate pt with muscle relaxant, midaz and fentanyl because VD is increased d/t the increased amt of fluids that prime the pump
- this is cause of recall with cardiac survery
- make sure perfusionist has anesthetic gas turned on
16
Q
What happens right as pt is put on bypass?
A
- pt cooling starts
- cease ventilation- disconnect the pt from vent?
- IV fluids shut off
- VA turned off
- make sure perfusionist has instituted anesthetic
- pull back swan catheter
- give NMB to prevent shivering
- Significant drop in BP
- hemodilution causes decreased viscosity
- rapid dilution of catecholamines
- aortic cross-clamp to prevent systemic extravasation of antegrade cardioplegic solution
19
Q
What are the hematological effects of CPB?
A
- Effects both extrinsic and intrinsic coagulation pathways
- Factor XII conversion to factor XIIa on various surfaces of CPB circuit
- Directly impairs platelet function
- rapid adhesion and conformational alteration of plasma proteins, ie von Willebrand factor (vWF) and fibrinogen
- platelet aggregation and detatchment due to shear forces
- Shear damage sets off intrinsic pathway of coagulation
- impaired coagulation + heparinization leads to bleeding problems
27
Q
What should you think about as you prepare to wean off bypass?
(table)
A
31
Q
What is the checklist for coming off bypass?
Step 1?
Step 2?
(chart)
A
32
Q
Describe the pressure volume loops of the LV.
(diagram)
A
