Cardiac Anesthesia Management Flashcards
1
Q
components of primary pre-op testing for cardiac surgery (5)
A
- EKG
- chest x-ray
- echo
- stress test (exercise, nuclear, stress echo)
- heart cath
2
Q
what things do we want to note from a pre-op EKG?
A
- rate
- rhythm
- ischemic changes
- chamber enlargement
- conduction blocks
3
Q
what things do we care about on a pre-op chest xray?
A
- cardiac/mediastinal/aortic silhouette
- pulmonary effusion
- pulmonary congestion
- evidence of implantation device
- previous surgical marks
4
Q
what things do we care about on a pre-op ECHO?
A
- anatomic measurements and calculated values (pertinent positives)
- valvular performance (w/ attention to stenosis and regurg of all 4 valves)
- systolic function (graded EF and any regional wall motion abnormalities)
- presence of effusions, air, thrombus, vegetation, or anatomicl abnormalities (PFO, ASD, etc.)
5
Q
what things from a preop stress test do we care about?
A
- type of test and performance summary
- ejection fraction
- EKG
- uptake abnormalities
- failure criteria
- regional perfusion distribution report
6
Q
what information from a pre-op heart cath do we care about?
A
- cardiac output measurement
- specific vessel findings and severity
- interventions performed (previous and current)
- an EF measurement with gradient measurements
7
Q
which heart test do we use to help us determine if the patient has aortic stenosis?
A
echo
8
Q
what items are a part of the basic setup for a cardiac case?
*monitoring devices only (10)
A
- ALL REGULAR MONITORS +
- art line
- CVL with transducer for CVP
- temp monitor - esophageal and bladder
- PAC
- neuromonitoring device (BIS)
- cardiac output monitor
- doppler
- echo/TEE
9
Q
what items are a part of the basic setup for a cardiac case?
thing that are NOT monitors or drugs
A
- warming device - fluid warmer at minimum, forced air warmers (bypass pump most effective)
- lab testing device - very hospital-specific
- pacemaker
- defibrillator with pacing
- banked blood available
10
Q
what labs are frequently monitored during a cardiac case?
A
- iStat or TEG
- ACT
- ABG
- electrolytes
- h/h frequently
11
Q
what drugs are used for cardiac procedures?
*tons
A
- induction drugs
- versed
- fentanyl
- etomidate
- anectine
- non-depolarizing muscle relaxant
- lidocaine
- heparin
- protamine
- vasopressors - ex. epi, neo, NTG
- diluted pressors
- antibiotics
12
Q
what type of temp monitoring is used during cardiac procedures?
any lil things you wanna keep in mind about it?
A
esophageal and bladder temp
esophageal temp may not be accurate when circulation is stopped
13
Q
what is the most effective in warming a patient having a cardiac procedure that requires CBP?
A
the bypass pump itself
14
Q
what dose of heparin is commonly used in cardiac procedures?
A
30,000 units
30 ml of 1000u/ml concentration is common dose
or 300 units/kg, depending on which page of the same MF document you look at :)
15
Q
key consideration with protamine
A
never open up, draw up, remove from cart, or prepare before needed
can lead to inadvertent administration and cause catastrophic and almost certainly fatal effects
never emergent med that needs to be prepared in advance
16
Q
benefits of an available diluted pressor syringe
A
- meds can be bolused if there’s a pump failure
- if IV/CVL failure, boluses can be given a different route while access is re-acquired
17
Q
at minimum, what pressors should be prepared for CV procedures?
what other meds are often added?
A
minimum: neosynephrine, calcium chloride, nitroglycerin
common to add: epinephrine, ephedrine, levophed
18
Q
what are three potential times for awareness when the patient might need versed?
A
- sternotomy
- re-warming - brain starting to function
- going on CPB - adds volume of distribution which dilutes out drug in body
19
Q
what are the three components of BP?
A
- HR
- stroke volume
- SVR
20
Q
what factors influence stroke volume?
A
contractility and preload
~ frank says the greater the preload the greater the SV
21
Q
what influences regional contractility?
A
ischemic factors
ex. poor blood flow from LAD to the anterior wall causing poor pumping of that area
22
Q
what factors influence global contractility?
A
entire myocardium becoming sluggish from…
- excess beta blocker
- excess (anesthetic?) agent
- hypoxia
- acidosis
23
Q
what factors affect cardiac output?
A
stroke volume and heart rate
24
Q
what is the best way to assess which parameter is causing a decrease in BP in order to initiate precise therapy?
A
TEE
25
what factors often influence the decision of which pressor to use?
* hospital/clinical preference
* availablity
* cost
26
epinephrine bolus dose
2-10 mcg
27
receptor effects when given the following doses of epinephrine:
0. 01-0.03 mcg/kg/min
0. 04-0.1 mcg/kg/min
\>0.1 mcg/kg/min
* 0.01-0.03: alpha: + / beta +++
* 0.04-0.1: alpha: ++ / beta: +++
* \>0.1: alpha: +++ / beta +++
28
dose of NE and the receptor effects associated
0.01-0.1 mcg/kg/min
alpha +++ beta ++
29
dose of dobutamine and receptor effects associated
2-20 mcg/kg/min
alpha: none / beta: ++
30
bolus and infusion dose of phenylephrine and receptor effects
bolus: 50-200 mcg
infusion: 10-50 mcg/min
alpha: +++ / beta: none
31
milrinone bolus and infusion dose
MOA
bolus: 50 mcg/kg
infusion: 0.375-0.75 mcg/kg/min
MOA: phosphodiesterase inhibition
32
BP, HR, SV, CVP, PA, SVR indicators for volume therapy
* BP - low
* HR - normal-high
* SV - low
* CVP - low
* PA - low
* SVR - low
33
BP, HR, SV, CVP, PA, SVR indicators for a vasopressor
* BP - low
* HR - normal
* SV - normal-high (high due to decreased afterload increasing EF)
* CVP - low
* PA - low
* SVR - low
34
BP, HR, SV, CVP, PA, SVR indicators for an inotrope
what else must be done?
* BP - low
* HR - normal
* SV - low
* CVP - normal
* PA - high
* SVR - normal
\*must also rule out ischemia
35
what would BP, HR, SV, CVP, PA, SVR look like in a patient with RV failure?
therapy indicated?
* BP - low
* HR - normal
* SV - normal
* CVP - high
* PA - normal
* SVR - normal
therapy: decrease PVR, increase inotropy, rule out RV ischemia
36
considerations for _home_ anti-coag meds prior to CV surgery
* we *must* know pre-op anti-coagulation meds
* some cases will need time for the med to be metabolized away prior to surgery
* some meds will want to be continued
* some meds we will want to reverse
37
2 main indications for blood products during surgery
* replace blood loss
* correct coagulopathies
38
what is the standard amount of blood products to have available for a cardiac procedure?
minimum 2 units PRBCs reserved for the pt
39
it is "imperative" to have suction connected to what two places for a CV case?
\*other than the pts suction for airway
* venous reservoir of bypass machine
* cell saver
40
methods to decrease chances of patient receiving donated PRBCs?
autologous donation
hemodilution
\*must coordinate with blood bank team
this is stupid.
41
what is cell saver?
what does it include/not include?
a machine that collects, filters, and returns the RBCs lost to suction back to the patient
does not give back plasma or plts
42
if blood loss is 2.5-3 L, how many liters of RBCs are returned?
1 liter - no plasma plts
43
what the implication of cell saver when there are large volumes being returned to the patient?
it indicates significant blood loss and the potential for coagulopathy
44
what is the most common anticoagulant used in cardiac surgery?
goal of use?
heparin - the goal is to prevent clot formation in the bypass pump ---- duh.
45
MOA of heparin?
effects?
MOA - **potentiate** the action of the endogenous antithrombin III (ATIII)
this action increases the inhibition of the clotting action of thrombin 1,000-fold
46
classic heparin dosing?
goal ACT?
300 units/kg
ACT \> 400 within 3-5 min
47
if ACT is not at goal within 3-5 min, what should be considered?
patient may have heparin resistance or an ATIII deficiency
48
what to do if patient has heparin resistance?
give additional dose of heparin
49
what do if the patient has ATIII deficiency
two options…
1. administer ATIII and then additional heparin dose — or
2. administer FFP and then additional heparin
50
what is HIT?
what commonly administered things can cause this?
what to do if HIT history/susceptible? (truly unsure what he means here so pls help)
* potentially fatal and incapacitating process caused by heparin
* can be caused by heparin flushes and AL fluids (and obvi heparin admin for bypass)
* careful attention to remove heparin from the supply area
51
when is protamine administered?
what will happen if administered early?
* only once CPB is completely disengaged
* administration while on bypass will cause catastrophic pump clotting and failure (Death X\_X)
52
protamine dose?
MOA?
1 mg of protamine per 100 units of heparin administered
MOA: electrostatic binding and inactivation of heparin
53
how to administer protamine?
why?
* administer slowly - decreases the likelihood of mild allergic reactions
* some use solu-set or slow bolus
* \*though some say true anaphylaxis may occur no matter the dose amount
* administer through PIV to reduce the severity of heparin response such as hypotension
54
possible routes of protamine administration
* PIV
* CVL
* direct injection into the heart
55
what are the two most commonly used antifibrinolytic agents in cardiac surgery?
indication for use?
aminocaproic acid (Amicar)
transexamic acid (TXA)
often used to reduce post-op micro bleeding and venous oozing
56
when should antifibrinolytics be given?
some recommend administering after therapeutic ACT achieved to avoid heparin interference for bypass
(but they do not affect ACT 🤷🏻♀️)
57
formula for SVR
normal range
SVR = (MAP - CVP) / cardiac output x 80
normal: 700-1600 dynes
58
formula for cardiac output
normal range of cardiac index
CO = HR x SV
normal CI: 2-4 L/min/m2
google - cardiac output alone cannot be a reliable indicator of cardiac performance when used alone since it doesn't take into account the patient's size
59
formula for ejection fraction
EF = (EDV - ESV / EDV) x 100
60
formula for coronary perfusion pressure
CPP = DBP - LVEDP
*fun fact per APEX that was brand new to me - can use PAOP for LVEDP*
61
normal PA value
15-30 / 5-10
62
normal CVP
5-10
63
what is one of THE MOST important principles to understand for a cardiac CRNA?
myocardial oxygen balance
64
principle components of myocardial oxygen demand
wall stress
heart rate
contractility
65
principle components of myocardial oxygen supply
coronary blood flow
oxygen content of the perfusing blood
oxyhgb dissociation curve
oxygen extraction
66
what is the primary focus for increasing myocardial oxygen supply in the absence of anemia and with an adequate O2 content?
coronary blood flow
67
what section of the heart muscle is most susceptible to ischemia?
the subendocardium of the LV
68
EKG changes seen in patients with subendocardial ischemia
* subtle ST/T wave changes
* ST-elevation does **not** result from isolated subendocardial event
69
5 ways to support O2 supply/demand balance
1. **keep the heart “unloaded”** to reduce wall tension and avoid an increase in contractility
2. **maintain afterload** to ensure CPP
3. **decrease contractility** unless contractility is markedly diminished (β blockers)
4. **decrease/minimize HR** (β blockers)
5. **maintain adequate blood oxygenation**
70
methods to keep the heart “unloaded” to reduce wall tension (3.5?)
* judicious use of preload (does this mean be careful with volume? why does he have to be so damn cryptic)
* nitroglycerin
* morphine
* other venous capacitance tools (?)
71
what's a good drug to use to maintain afterload to ensure adequate CPP?
which is better for coronary perfusion - hypotension or hypertension?
neosynephrine
hypertension better
72
what occurs when myocardial oxygen demand exceeds supply?
ischemia — DEATH
73
factors impacting cardiac O2 supply
* coronary artery anatomy
* diastolic pressure
* diastolic time
* O2 extraction (Hgb, SaO2)
74
factors impacting cardiac O2 demand
* HR
* preload
* afterload
* contractility
75
chronology on patient arrival to OR
~ set up kinda things ?
idk this is stupid
1. oxygen
2. standard non-invasive monitors
3. print EKG strip
76
pros vs cons for placing lines before induction
pros:
* can see abnormal reading prior to start of procedure
* no worry of emergent line placement
cons:
* awk
* can cause increased HR and possible ischemia
77
when should lines be placed for cardiac surgeries? why?
* artline and PIV prior to induction CVL/PAC after
* allows for quick monitoring of cardiac output during induction without the stress of CVL placement
78
why does Sanford think you shouldn't place a PA/CVL under conscious sedation before cardiac surgery?
pt breathing under the drapes can cause hypercapnia and potential airway loss
(benefits don't outweigh the risks)
79
after non-invasive and pre-induction monitors are in place and a securing strap is on the patient, what are the next steps taken?
external defibrillator pads are placed
pre-oxygenation is initiated
induction then begins
80
pros vs. cons for a high dose narcotic anesthetic technique
pros: smooth induction, hemodynamic stability, more than adequate blunting of stimulation
cons: risk of stiff chest syndrome, awareness, and prolonged time til extubation
81
pros vs. cons of a narcotic anesthetic technique with generous benzos
pros: addresses the potential for awareness (vs. narcotic only technique)
cons: can result in prolonged extubation times
82
what is a balanced anesthetic technique?
mixing smaller amount of different drugs to allow for faster metabolism and wake up with less side effects
83
example of common meds used for a balanced anesthetic technique to address:
initial amnesia
SNS stim/pain
ongoing amnesia
amnesia: midazolam
SNS stim/pain: fentanyl
ongoing amnesia/unconsciousness: inhalation agent
84
recommendations regarding muscle relaxants in CV surgical pts during induction
center specific
controversy over non-depolarizer vs SCh
85
induction/intubation considerations for pt needing TEE
patient needs true RSI without mask ventilation
air in stomach obstructs views
86
one suggested technique regarding induction and timing is:
make the induction \_\_\_\_, but not necessarily \_\_\_\_
\*idk how to word this halp
make induction _smooth_, but not necessarily _slow_
87
how should NMBs be dosed during CV surgery?
depends on nerve stimulation monitoring
88
pros of using nerve stimulation monitoring during CV case
helps to avoid unnecessary drug dosing which facilitate timely extubation post-op
avoids unanticipated spontaneous breaths and movement intra-op
89
what changes during surgery can affect the metabolism and excretion of our anesthetic agents?
* temperature
* pH
* organ perfusion
* renal output
90
what factors should be considered when dosing muscle relaxants?
changes in volume of distribution
rewarming
circulatory arrest (meds not circulating)
91
what monitors should be implemented after induction but prior to surgery start? (7-8)
(above the standard monitors)
* art line - if not already in place
* CVL - if not already in place
* BIS monitoring\*
* cerebral oximetry\*
* core temp - esophageal and bladder (rectal can be used instead of bladder if needed)
* cardiac output monitor (via PAC, AL or TEE so unsure why he included)
* PAC
* TEE
92
what are fundamental parameters we can collect from an art line waveform that allow for fine-tuning to “the vigilant anesthetist” ---- lol
* pulse pressure
* systolic pressure variation
* hemodynamic status
93
do we want our monitor art line wave form set to optimized scale or fixed scale?
why?
fixed scale
to allow us to better see changes in the waveform
94
why is having the art line waveform set to “optimum scale” deceptive?
keeps the screen full no matter the pressure - “deceiving the casual eye into thinking the pressure is actually satisfactory"
unable to appreciate systolic pressure variation
95
how does bypass affect radial art line readings & why?
reads falsely low by 10-30 points due to hypothermia and vasoactive medications
\*will return to same pressure as other sites following rewarming and reduction of vasoactive meds
96
which side is preferred for radial art line cannulation?
why?
left - bc apparently the surgeon leans on the right arm
97
reasons that some centers empirically place art lines on one side?
* some cases require radial artery harvesting for implantation for coronary flow
* the retractor may impede or occlude the subclavian artery and dampen the radial site reading
pls change if this isnt what that part means tysm
98
what is one intervention the CRNA can do to help prevent/minimize positioning issues related to an art line?
\*TW this is dumb as hell
place a wrist splint
99
what are the three primary uses of a CVL?
* measure CVP
* access point for large and/or rapid volume, meds, blood and fluids
* as an introducer for central catheters such as PAC, coronary sinus catheter, LV drain, and pacing wires
100
what are the two most common sites for CVL insertion?
which of those has a big advantage/what is the advantage?
* right subclavian
* right internal jugular - easy to access, can guide catheters directly without extensive turns
101
what are the implications of administering cell saver, PRBCs, and fluids without warming?
* drastically decrease temp
* prevent management of coagulopathy
* impact metabolism
* impair cardiac function
\*so warm your fluids ladies
102
BIS and cerebral oximetry ---
which is used to monitor level of consciousness?
which helps determine tissue perfusion?
BIS = monitor LOC
cerebral oximetry = monitor tissue perfusion, esp when there is potential for brain blood flow to be compromised
103
it is difficult to resume stable autonomous electrical activity below \_\_\_º C after bypass
34º C
104
what is the primary means of cooling and warming the CV patient?
what extra device is used during re-warming?
* bypass pump is main method
* forced air warmer should be used during re-warming to assist and also maintain temp following coming off pump
105
how should temp be measured in CV surgery patients?
considerations for oliguric patients?
* typically measured esophageal and bladder
* rectal can be measured instead of bladder in oliguric patients bc bladder temp may be inaccurate
106
T/F: cardiac output monitors are always beneficial
false
“only beneficial when the user understands what data is being derived, implications of how that data is applicable, and then can take that information and introduce it into the management therapy”
107
examples of derived data from a cardiac output monitor
* cardiac output
* cardiac index
* systemic vascular resistance
* stroke volume
* stroke volume variation
108
T/F: modern cardiac anesthesia guidelines indicate the regular use of TEE for cardiac procedures
true
109
data that can be seen from use of a TEE
real-time direct data on:
* regional and global cardiac performance
* volume status
* valvular status
* intra-cardiac air
* aortic assessment
110
why are TEEs becoming standardized for cardiac anesthesia?
* sensitive to abnormalities
* direct assessment capability
* multi-faceted evaluation properties
111
does TEE directly or indirectly assess volume and contractility?
directly
112
what are the 4 classifications for regional wall motion?
normal
hypokinesis
akenesis
dyskinesia
113
what is the utility of a PAC?
* assess right and left heart function
* assess volume status
* assess cardiac output
* assess pulmonary function
* initiation of atrial/ventricular pacing
114
consideration of PAC when going on bypass
catheter tends to advance when on bypass - withdraw the catheter 3-5 cm to avoid inadvertent wedging
115
intra-op complications from use of PAC
* looping
* RBBB
this is just based on previous lectures but I think these are more assoc. with insertion?
116
what could potentially occur in a patient with known LBBB during PAC placement?
interventions?
RBBB can occur in conjunction with LBBB causing complete heart block
requires immediate pacing and resuscitation
117
this is stupid. so on the back there's some tips for how to stay organized if ya wanna take a look.
* label your shit
* ensure vascular access points are clearly labeled, clearly connected, functional, and secured
* build structure so that once patient is draped you are confident what is under drapes, how to access critical points, that connections are secure, that fragile points are padded
* know what to do at any given point for any given crisis and how to initiate emergency therapy for the airway and resuscitation
118
what are the 3 “keys to success” for cardiac anesthesia
1. *vigilance*
2. *understanding of oxygen supply and demand*
3. *proficiency in pharmacologic management*
119
when should antibiotics be administered?
prior to surgical inicsion
120
optimal tidal volumes for CV surgery
6-8 ml/kg
121
optimal ETT size for CV surgery patients
\*bigger than average for more comfortable post-op ventilation (staying intubated & going to ICU)
males: 8.0-8.5
females: 7.5-8.0
122
times during procedure that it might be required to suspend ventilation?
what might result?
sternotomy, surgical exposure, and visualization
may result in hypoxia, hypercapnia, systemic acidosis
123
what ventilation strategies may be beneficial during peri-op time for CV patient?
* recruitment maneuvers
* PEEP
* mild hypocapnia
124
what is the long ass surgical sequence for cardiac procedures?
1. access the heart
2. collect the vein/artery or other anastomosis conduit
3. \*\*\**_heparin_* here!
4. enable bypass and cannulation
5. arresting the heart
6. grafting new conduit to coronary artery vasculature
7. restarting heart
8. separating from bypass
9. reversing coagulopathy and surgical packing
10. closure
125
complication of sternal saw
what measures must we take during use?
* ….lung injury
* vent must be disengaged with APL completely open to allow deflation of lungs away from sternum
126
what three vessels are typically harvested for LAD circulation?
* left internal mammary artery from chest wall
* saphenous vein
* radial artery
127
what should the CRNA consider doing during mammary artery dissection?
decreasing tidal volumes to avoid lung pushing into field
128
implications for internal mammary artery harvesting (3)
* lungs can encroach into the surgical field - minimize tidal volumes
* left art line may be dampened if retractor for internal mammary artery dissection compresses the subclavian artery
* be aware of preexisting subclavian stenosis - precludes the use of internal mammary artery (bc its the origin of IMA)
129
what is the most common vessel to harvest?
why is it the most common?
saphenous vein
its the most cosmetically appealing incision sites and yields multiple pieces of vein for implantation
130
T/F: saphenous vein harvesting has a high amount of stimulus and must be done after sternotomy due to the amount of drugs required to blunt stimulation
false - minimally stimulating and may be initiated prior to sternotomy
131
considerations for radial artery harvesting
why is this important?
don't put an art line in the artery to be harvested - then we'll piss off the surgeon
also put all the other vascular access and monitors on the opposite side
\*typically done on the non-dominant side
132
what medication might be administered post-bypass when the radial artery is harvested?
why?
calcium channel blocker - to prevent vasospasm of the radial artery and creation of a pseudo-coronary occlusion
133
what is the next step in the sequence of surgical events after the conduit is obtained?
heparin is administered for bypass
134
how is heparin ususally administered?
what lab is drawn after and the timing?
* heparin adminstered in central access
* TWO LABS! - ACT and ABG drawn 3-5 min after adminstration
135
where are the bypass cannulas placed?
what should we do to pts BP and why?
cannulas placed in ascending aorta and right atrial appendage/RA/IVC
SBP should be dropped to 90-100 to avoid wall tension on aorta during cannula insertion
136
next step in sequence of events after cannulas placed?
cardioplegia device (needle and tubing) is inserted into the aorta
137
FYI - dissection, false lumen, improper placement, etc. of the aortic cannula may result in the inability to deliver blood back to the patient
bc its gotta be in the real aorta ya know
138
FYI - improper placement of the venous cannula can result in venous engorgement, obstructive compartments such as SVC syndrome, and increased risk for stroke and tissue damage
bc its gotta get out of the body ya know
139
we all know that bypass means the patient has blood diverted from their heart to the pump to do the work instead
next
140
what ventilation/volatile differences are there when the patient goes on bypass?
ventilation is discontinued
volatile is added by the perfusionist to the bypassed blood to maintain GA instead of being delivered into pts lungs
141
what drugs are typically redosed when the patient goes on bypass?
amnestic
narcotic
muscle relaxant
142
why are patients cooled when on bypass?
to reduce body and brain metabolism
143
what is the purpose of an aortic cross clamp?
to isolate coronary blood flow
144
where is the cardioplegia device placed?
between the aortic valve and aortic cross clamp - “aortic root”
solution flows down through the coronaries and stops the heart
145
what areas of the body do not recieve oxygenated blood while on bypass?
ONLY the coronaries
146
what temperature is the heart reduced to while stopepd?
why is it cooled?
usually 10-15º C
coolness decreases the metabolism & cardioplegia arrests the heart
147
is systemic cooling done for systemic protection, cardiac protection, or both?
only systemic protection - only provides a small effect on heart
\*cardiac cooling is for cardiac protection
148
what is an indicator of satisfactory delivery of cardioplegia to the coronaries - aside from the obvious that the heart stops
decreased temperature of heart muscle distally
149
what could cause an incomplete arrest and maintained metabolism after administration of cardioplegia?
whats an intervention to fix this issue?
abnormal coronaries
can place catheter in coronary sinus and deliver cardioplegia to the distal tissue in reverse flow
150
what comes next in the sequence of events after adminstraiton of cardioplegia and arrest of the heart?
grafting of the coronaries
complete with proximal attachment to the aorta
151
what comes next in the sequence of events after coronary grafting is complete?
rewarming and removal of aortic cross clamp
152
what causes the heart to start beating again?
* cross clamp is removed, allowing blood to flow into coronaries
* cardioplegia is washed away and the heart rewarms
* the heart starts itself - but no blood is moving through it
153
what medications are administered after removal of the cross clamp to address hyperkalemia and reperfusion dysrhythmias?
* lidocaine
* calcium
* magnesium
154
what interventions are taken to achieve rate and contractility control after aortic cross clamp is removed?
* vasoactive infusions
* pacer
155
how to reinstate ventilation after removal of cross-clamp
manually inflate lungs with careful recruitment to avoid overpressurizing and damaging lungs
ensure both lungs are ventilating
156
how is blood put back in the heart when trying to come off bypass?
(slow or all at once?)
pump is partially clamped to allow blood flow into heart
pump outflow is *_gradually_* weaned as patient's cardiac output tolerates (inotropes often used)
157
what are we assessing for when using a TEE to wean off pump?
* absence of intra-cardiac air
* intra-cardiac volume
* contractility
* valve function (if valve procedure was done)
158
when is protamine administered?
once the heart is pumping well and cannulas are removed
159
what lab is drawn after protamine is given?
what are we looking for?
ACT - verifying pre-bypass coagulation
160
speed of protamine adminstration?
why?
considerations?
administer slow since it can tank BP
have phenylephrine ready
161
how is cardiac function assessed after separation from pump and protamine adminstration?
doppler signal
162
what is the next step in the sequence of events after pump separation and verification of proper cardiac function/controlled bleeding?
pleural and mediastinal chest tubes placed
closure of sternum
163
considerations and complications during sternal closure
* manually ventilate to avoid hyperinflation and potential injury from sternal wire
* watch airway and right heart pressures
* chest closure could cause right heart compression and cardiac collapse
* lung recruitment after closure is a cool thing to do
164
what is required for patient transport post-op?
* oxygen
* monitoring
* ventilation device
* emergency meds that would allow for reintubation if necessary
* emergency meds that can manipulate pressure and HR (need meds to raise and lower)
* ability to institue pacing if EKG has been abnormal or if valve surgery
165
goal time for extubation post-op?
benefits associated? (5)
* less than 8 hours
* shorter ICU stays
* shorter hospital stays
* decreased cost
* lower infection rates
* less complications
166
suggestions for how to facilitate timely post-op extubation?
* avoid post-op muscle relaxants
* consider reversal of muscle relaxant
* utilize short acting narcotics
* utilize short acting sedatives (propofol/dexmedetomidine/midazolam better than lorazepam/diazepam)
167
what is the average prime volume for a bypass pump?
1.5 L
168
effects of priming the pump with crystalloid
* reduced viscosity (good)
* diluted H/H (bad)
* decreased O2 carrying capacity (obvi bad)
* larger Vd can dilute meds - need to redose
\*pt more likely to need transfusions if crystalloid primed pump
169
you think your patient has an ATIII deficiency. what can you administer to allow them to anticoagulate properly?
* administer exogenous ATIII or FFP (contains ATIII)
* then give additional heparin dose
\*if low ATIII, heparin has nothing to act on
170
techniques for blood conservation when patient needs procedure that requires CBP?
what are two examples he gave of patients that would benefit from these techniques?
* autologous blood banking (pt will get their whole blood back vs just PRBCs with cell saver)
* autologous hemodilution and re-transfusion
* retrograde autologous priming (RAP) of bypass pump
good for dialysis pts that wont tolerate 1.5 L of extra fluids or Jehovah's witness that cant accept blood
171
what device is necessary to allow for cardioplegia to flow into the coronaries?
aortic cross clamp
172
good and bad effects of cardioplegia during bypass?
good: stops the heart, cools the heart
bad: removes oxygen supply
173
what body temperature allows for benefit of myocardial and systemic metabolism reduction and results in superior neurologic recovery?
28º C
174
describe antegrade cardioplegia delivery
cardioplegia introduced into aortic root and flows through the coronary arteries in the direction of normal blood flow
175
describe retrograde cardioplegia administration
when would it be useful?
cardioplegia introduced into coronary sinus (venous) where it flows backwards through the coronary arteries and exits into the aorta
\*useful when blockage would obstruct spread of cardioplegia if given antegrade
176
classic fluid management for CV surgical cases involves what three components?
* calculating fluid deficits
* hourly maintenance
* third space losses
177
how long does it take the patient's entire blood volume to cycle through the bypass machine?
1 min
178
current trend is to minimize crystalloids to less than what prior to bypass?
\< 1 L
179
FYI - reason for all the access is for post-op administration of blood/crystalloid/colloids but we're limiting fluid pre-op
🙄
180
goals for aortic valve stenosis
* full preload
* avoid tachycardia
* maintain perfusion pressure with afterload maintenance
181
goals for aortic valve regurg
* full preload (may already be in overload)
* maintain rate
* decrease afterload
182
goals for mitral stenosis
* full preload
* avoid extreme increase in afterload, but maintain
* maintain contractility
* avoid tachycardia
183
goals for mitral valve regurg
* full preload (may already be in overload)
* decrease afterload
* maintain rate
184
what is the BIG difference in management of CABG vs aortic dissection?
timing - aortic dissection needs to be in OR ASAP
\*mortality in ascending dissection increases 1-2% per hour after onset of symptoms
185
ascending vs descending aortic dissection —
which needs surgical treatment?
which can have medical or surgical treatment?
ascending = surgery
descending = medical or surgical
186
where does a descending aortic dissection occur?
distal to the L subclavian
187
inital pre-surgical interventions we need to take for an aortic dissection patient (4)
* avoid HTN
* manage contractility (may be influenced by decreased coronary perfusion, dissection, or tamponade)
* prep for circulatory arrest
* obtain significant vascular access
188
what are three ominous signs in an aortic dissection patient?
what can they indicate?
* cerebral changes = diminished blood flow to brain
* coronary symptoms = diminished blood flow to myocardium
* changes in peripheral motor function = diminished blood flow to spinal cord
189
what are the 2 indicators of severe aortic dissection progression?
* cardiac tamponade
* acute aortic valve insufficiency
190
T/F: you can take your sweet ass time getting your aortic dissection patient into the OR
false
191
minimally invasive cases:
\_\_\_\_ invasive incision
\_\_\_\_ invasive anesthesia
_minimally_ invasive incision
_maximally_ invasive anesthesia
192
do minimally invasive procedures involve sternotomy?
~no~
\*wow, shocking
193
three approaches/procedures that can be done during a minimally invasive cardiac procedure
* coronary bypass
* valve repair
* valve replacement
194
\*\*\*idk what this means\*\*\*
what extra anesthesia responsibility would we have in a minimally invasive cardiac surgery?
facilitating the portions in a non-visualized fashion
\*\*\*what\*\*\*
\*also have no idea what this means, must be something only DS could understand\*
195
difference in ventilation strategy in minimally invasive CV procedure? why?
one lung ventilation
to allow surgical access to the heart through the pleural space
196
how is cardioplegia adminstered in a minimally invasive procedure?
retrograde
placement of a coronary sinus catheter via CVL
197
what types of surgical catheters are used during minimally invasive procedures?
how do we verify placement?
* femoral arterial cannula
* femoral venous cannula
* aortic endoclamp
* pacing PA catheters
\*placement verified with TEE
198
do patients having a minimally invasive cardiac surgery go on bypass?
yep - give em heparin
199
what is the premise of an off-pump CABG?
the coronary grafts are placed via routine sternotomy but without arresting the heart or going on cardiac bypass
200
what is one component of off-pump CABG that impacts anesthesia?
how do we try to manage this?
* the surgical need to stabilize heart for surgical access but in such a way that filling and ejecting is not compromised
* often requires:
* volume management
* pharmacologic support
* frequent communication with the surgeon
201
EKG and TEE monitoring is recommended for off-pump CABG due to increased heart stress and risk for ischemia.
what might make these sub-optimal assessments?
mechanical displacement of the heart
202
during off-pump CABG, what can be beneficial during periods of stress to fill the heart that impeded from natural filling?
fluid boluses
Trendelenburg position
203
what monitoring device is “imperative” during off-pump CABG?
“an accurate and perfectly functioning artline”
🙄🙄🙄
204
do off-pump CABG pts receive heparin?
if yes - goal ACT?
yep - idk why though
\>300
205
what is an ideal vessel for grafting in off-pump CABG?
why?
internal mammary artery
b/c it doesn’t require proximal anastomosis (has native blood supply)
(a vein graft from aorta to heart requires partial clamp of the aorta and increases the risk of neurologic event)
206
advantage and disadvantage of off-pump CABG
* advantage: the lack of bypass effects (dilution, capillary permeability, renal, inflammatory etc)
* disadvantage: risk of ischemia from stress without the “rest” of bypass
207
indications for balloon pump (3)
* presence of ischemia
* potential ischemia
* poor cardiac output requiring augmentation
208
relative contraindications for balloon pump (3)
* aortic disease
* aortic valve disease
* surgical insult to the aorta
209
how does a balloon pump work?
* a balloon inflates during **diastole**
* that increases proximal aortic pressure and thus **coronary perfusion pressure**
* deflation just prior to systole allows the heart to have a decreased workload requirement to eject blood
210
ideal placement of a balloon pump?
how to verify placement?
balloon tip distal to the left subclavian artery
verify with TEE or fluoroscopy
211
goal of using a balloon pump?
improve coronary perfusion
decrease cardiac workload
\*may O2 supply \> O2 demand
212
what do we monitor in a patient with a balloon pump?
distal pulses &
UOP
213
diastolic goals with balloon pump
| (not number, but general goal)
augmented diastolic pressure should exceed the unassisted systolic pressure
214
what does the shaded portion represent?
balloon pump inflation
215
what is an impella (Abiomed) device?
how does it work?
* ventricular assist device
* device sits in LV, and blood is siphoned into the pump catheter and pumped into the aorta on the distal side of the aortic valve
216
who might benefit from an impella (Abiomed) device?
support of the LV during
* acute MI
* cardiogenic shock
* post-bypass
217
what is a Tandem Heart?
functional difference in it vs an impella?
ventricular assist device
can add an oxygenator to it unlike in the impella (aka tandem lung!!!!)
218
what is a TAVR procedure?
transcatheter aortic valve replacement — placement of an expandable valve inside the native aortic valve
\*not considered true valve replacement since native valve remains
219
how is the new valve placed in a TAVR?
* valve is threaded over a guidewire from either the trans-apical (of the LV) or from the distal aortic route (via femoral artery)
* once the valve is positioned inside the native valve, rapid ventricular pacing is initiated to minimize cardiac output
* valve is then expanded and deployed by balloon expansion and begins to function
220
indication for TAVR
severe aortic valve stenosis
221
anesthetic implications for TAVR procedure (6)
* current co-morbidities
* heparinizing
* impaired hemodynamics
* intra-operative TEE
* management of complications
* type of anesthesia
all of which may become intensive and dynamic
222
what type of anesthesia technique is classically used for TAVR?
what is becoming trendy?
classic = GA
~\*~trendy~\*~ = MAC
223
T/F: TAVRs are often very sucessful and potential complications are not a big deal
false —
“while often very successful, the complications of the surgery may be catastrophic”
true dat
224
if using the transapical approach for TAVR procedure, what is the location for balloon insertion?
~ obvi apical area but be specific
5th intecostal space mid-clavicular line
typically where point of maximal impulse is
225
what is the purpose of hypothermic circulatory arrest?
to way cool the body to decrease CMRO2
-to prevent exsanguination if the aorta can't be clamped before opening it, to decrease metabolic demand and preserve tissues
226
ideal time limit for circulatory arrest
15-20 min max
227
what should the CRNA remeber & anticipate in a case where hypothermic circulatory arrest is indicated?
remember:
* meds cant be given when their blood aint pumpin, so give ur drugs early
* pad all the bony things real good
* cold body = platelet inactivation, vasodilation (???), etc. (???)
anticipate:
* severe vasodilation (pt 2 ???)
* coagulopathy
* pump failure
228
pros/cons of etomidate for induction of cardiac surgeries
pros: hemodynamic stability
cons: adrenal suppression
229
pros/cons of propofol in CV surgery
pros: decreased SVR
cons: avoid if cardiac frailty
230
pros/cons of ketamine in CV surgery
increased HR and BP are both pros and cons - useful in some patients but detrimental to CAD patients
