Cardiac anesthesia 3 Flashcards
Preventing emboli for cerebral protection includes
hypothermia
blood gas management
adequate BP
cerebral oximetery
After coronary anastomosis, you will start to
rewarm patient b/c it takes 30-40 minutes to gradually rewarm
Rewarming begins
prior to aortic cross-clamp removal
with last distal anastomosis in angioplasty procedures or when all the valve sutures are in and knots are being tied down
_______ may occur during rewarming so it is important to give
amnestic drug
In preparation for coming off bypass, core temperature MUST be
above 35 degrees C (eventual target is 37 degrees C)
Preparing to come off of bypass includes correction of
labs, ABG
-fix K+ first, then acid-base & hematocrit
Describe the steps for coming off of bypass.
temperature correct labs inflate lungs removal of cross clamp defib heart rate rhythm venous return line clamped slowly measure CO monitor SVO2 shivering- give muscle relaxant airway- turn the vent on!
Blood sugar should be maintained
<200 because patients are pone to sternal wound infection
Giving_________ results in less risk of afib afterwards
magnesium
Removal of the cross clamp involves giving
hot shot (cardioplegia to start heart)
Describe the heart rate when coming off of bypass
paced or SR at sufficient rate (80-90 bpm)
Describe the rhythm when coming off of bypass.
AV paced or V paced
need adequate rate around 90 (will turn pacing rate down later in ICU)
Measuring CO includes
watching TEE for LV failure, monitor PA and arterial line presures
Measuring SVO2 is to watch for
increased demand or decreased delivery
When the perfusionist begins to turn down flows and allow RA to fill, we should look for
PA and a-line pressures to increase
Prolonged cross-clamp time significantly correlates with
major post-operative morbidity
When the cross clamp is coming off, reperfusion, although essential to survival, may
paradoxically cause myocardial damage and limit the extent of recovery
Complications of aortic cross clamp include
hemorrhage (at cannulate site), dislodgement of atheromas (clots) and aortic dissection
ST elevation may indicate
air left in the heart
When defibrillating a patient during cardiac surgery (open chest, direct contact defibrillation), defibrillation is typically at
10-30 joules
When coming off bypass, give
protamine slowly at 1 mg/100 un of heparin given- wait until all the catheters are out to make sure you don’t crash back onto bypass
When the chest is closed, cardiac tamponade may occur, the heart is
squished and team may have to open back up if not tolerated
Coming off of bypass includes examining for
contractility
bleeding
systemic pressure in relation to PA pressure
Describe contractility related to bypass.
the best monitor we have for coming off bypass is the eye
look at the heart to see how it is filling
heart needs adequate contractility to come off CPB
look at TEE: volume, wall motion, valve function
Post CPB challenges include
recall and neurocognitive changes bleeding organ hypo-perfusion non-pulsatile blood flow, emboli, thrombi systemic inflammation response residual hypothermia
Coming off of bypass may require the use of these drugs:
inotrope or afterload reducer
Steps for coming off of bypass include:
rewarm correct labs deair closing hot shots cross clamp off heart fibrillates--> defibrillate ventilate pt
Post CPB challenges related to bleeding may be due to
loss of clotting factors fibrinolysis thrombocytopenia surgical blood loss transfusion reaction vessel trauma metabolic by products
Extended CPB and cross-clamp times makes it
HARDER to wean off CPB
Reperfusion interventions include:
correct metabolic abnormalities
spend time “paying back” by re-perfusing the empty heart at adequate perfusion pressure (typically 20-30 minutes)
allows heart time to recover by washing out metabolic by products
if exceptionally long clamp time, consider IABP
Protamine may cause _________ which is why it is given slowly!!!
pulmonary hypertension and right heart failure
protamine works by
neutralizing and reverse effects of heparin, heparin is unable to form a complex with ATIII
The half-life of protamine is
shorter than heparin- on the order of 30 to 60 minutes which is the reason for “heparin rebound”
Protamine may cause
type I (histamine release), type II (anaphylactoid), or type III (bad) allergic reactions
Protamine may be administered via
peripheral vein
Protamine has anti-coagulant effects that are not seen until levels of
2-3x the normal reversal dose are given (weak anticoagulant at normal levels)
A final ACT should be drawn
15-30 minutes postop to ensure adequate reversal
Transport post CPB includes
ambu bag & O2 tank
monitor: ECG, arterial line
emergency drugs
keep surgical table sterile until out of room
recheck breath sounds after moving to bed
attach to vent in ICU & recheck breath sounds
Transport assistance is needed in the form of a surgeon, anesthesiologist or another CRNA
