Cardiac Anesthesia Flashcards
1
Q
What questions are important in pre-op before placing the TEE probe?
A
Dysphagia, swallowing problems, esophageal surgery, h/o esophageal obstruction, h/o EGD (and results)
2
Q
What do you need to consent the patient for?
A
GA, arterial line, central venous line, +/- PA catheter, TEE, post-op ICU stay / intubation
3
Q
What do you need to present in your plan?
A
- Induction (+HR/BP goals)
- Cannulation plan (“Full/Ao/RA” format)
- Graft plan (radial/LIMA/RIMA/BIMA/SVG)
- TEE?
- Airway
- Access (TLC vs. cordis)
- Blood products
- Other
4
Q
What conditions is etomidate useful for?
A
Low EF (very) or severe stenotic valvular disease
5
Q
What lines do you need to prepare at bedside?
A
1) Bolus line –> Cordis side port or brown port of TLC (1L NS on half-walrus tubing attached to Go4)
2) VIP line –> VIP of PA or white port of TLC (1L NS on microdrip w/ Go4)
3) 4-channel Alaris pump w/ Amicar (7.5g x 30min, then 1.25g/h) + 3 others
6
Q
What premixed bags should you have ready?
A
1) Phenylepi 320mcg/cc
2) Epi 16mcg/cc
3) Norepi 32mcg/cc
4) NTG 40mcg/cc
7
Q
What do you need for access?
A
A-line, PA line, TLC or Cordis kits
8
Q
Before sternotomy, what do you need to give?
A
1000mcg fentanyl to minimize hemodynamic shifts
9
Q
What do you need to do with sternal saw?
A
Hold ventilation
10
Q
3min after giving heparin, what do you do?
A
Draw ACT (+compare to baseline)
11
Q
Before aortic cannulation, what must you reduce SBP to?
A
90-100
12
Q
Before CPB… what do you need to do for fluids
A
Empty urine + record IVF
13
Q
Once on CPB, what do you need to do? (13)
A
1) Turn off ventilation
2) Remove pulse ox
3) Place machine on CPB mode
4) Stop all infusions (except Amicar, insulin)
5) Record times for “CPB on”, “aortic x-clamp on”
6) Prepare transport items for ICU
7) Maintain pressure 50-70
8) Monitor BIS
9) Monitor urine output
10) Hang pressors/inotropes + have boluses ready
11) Give rewarming drugs to perfusionist
12) Set up labels/paperwork/tubes for post-CPB labs (CBC, Coags/Fibrinogen, ACT/ABG)
13) Set up propofol GTT for ICU transfer
14
Q
What is the protamine test dose?
A
1cc (10mg)
15
Q
What are the side effects of protamine?
A
Hypotension, pulm HTN, anaphylaxis
16
Q
How fast should you give protamine?
A
1-2cc q 1-2min
17
Q
What should you give in sign-out?
A
- ICU pause to confirm patient and procedure
- Brief HPI (co-morbidities, functional status, ALL/Med)
- Airway (easy or not, i.e. Does anesthesia need to be there for extubation?)
- Last dose antibiotics, neuromuscular blockage reversal
- Brief operative course
- Induction/pre CPB - any problems?
- Coming off CPB – pressors, arrhythmias/defib, underlying rhythm/pacer settings, new ekg changes/regional wall motion abn, post-op EF, etc.)
- Current drips
- Access
- Ins/outs
18
Q
What antibiotics are generally needed for a VAD?
A
Vancomycin - based on weight
Ciprofloxacin - 400mg
Fluconazole - 200mg
19
Q
Amicar dosing
A
7.5g load over 30min, 1.25g/h infusion after until after CPB
20
Q
Amiodarone dosing to break VF/VT
A
150-300mg IV
21
Q
Amiodarone dosing for infusion
A
150mg over 10min, drip 1-2mg/min of 720mg/150cc D5W (12.5cc/hr)
22
Q
Dexmedetomidine dosing
A
1mcg/kg load over 10-30min, 0.3-0.7mcg/kg/hr infusion
23
Q
Dobutamine dosing
A
1mg/cc @ 2-10mcg/kg/min
24
Q
Dopamine dosing for D1 action
A
1-3mcg/kg/min of 1600mcg/cc
25
Dopamine dosing for B1/B2 action
3-10mcg/kg/min
26
Dopamine dosing for alpha action
>10mcg/kg/min
27
Epinephrine dosing for beta action only
1-3mcg/min of 16mcg/cc (4mg/250cc)
28
Epi dosing for beta>alpha
3-10mcg/min
29
Epi dosing for alpha = beta
>10mcg/min
30
Esmolol dosing
5-10mg bolus, 50-200mcg/kg/min infusion
31
Insulin dosing
1 unit/cc, check BG every 30min
32
Lopressor (B1) dosing
5mg q5-15min
33
Labetalol dosing
5-10mg bolus, up to 300mg/max
34
Milrinone dosing
50mcg/kg load, 0.25-0.75mcg/kg/min infusion
35
Nitroglycerin dosing
10-200mcg/min
36
Nitroprusside dosing
0.1-10mcg/kg/min
37
Norepi dosing
1-30mcg/min to effect
38
Propranolol dosing
0.5-1mg
39
Propofol dosing
0.5-1mg bolus
40
Vasopressin dosing
0.01-0.1U/min
41
What is a normal ACT?
80-160s
42
What is the ACT goal?
>350-450s (depends on location)
43
Why is the aorta cannulated first?
The aorta is cannulated first so that if there is a significant event (e.g. a tear during insertion of the venous cannula or a malignant arrhythmia) there is a way to deliver volume into the arterial circulation and maintain perfusion to the patient while CPB is being established.
44
What is “Testing the line”?
“Testing the line” means that the perfusionist checks the pressure required to move fluid through the arterial side of the circuit and into the aorta. If this pressure is too high, it may be a sign that the cannula is not in the lumen of the aorta, which could lead to an aortic dissection when CPB is initiated. To “test the line,” the perfusionist transfuses 50-100cc of fluid at 1L/min into the arterial cannula. There is a pressure gauge on the arterial line from which the perfusionist reads the pressure.
45
What is the purpose of the aortic X-clamp?
The aortic cross clamp goes on to effectively separate the systemic and coronary circulations. The reason for this is that the cardioplegia is administered into and needs to stay within the coronary circulation in order to stop the heart. If the cross clamp was not present, the systemic flow would also go through the coronaries and wash out any of the cardioplegia, making it impossible to stop the heart. REMEMBER: Once the aortic xclamp is on, the myocardium is rendered ischemic.
46
In what two ways may cardioplegia be administered?
Cardioplegia is given either anterograde (down the coronary arteries via a small cannula that is placed in the aortic root between the aortic valve and the cross clamp) or retrograde (via the coronary sinus).
47
What are the necessary steps for stopping CPB?
In order to adequately perform the cardiac output, the heart must have an acceptable rate, rhythm, and contractility. Afterload, electrolytes, and temperature must be normalized.
48
When is it safe to give all protamine?
When ALL cannulations removed
49
When should you use a PA catheter?
These measurements are helpful when faced with poor left ventricular function, valvular disease, recent MI, ARDS, massive trauma, major vascular surgeries, or when there is a critical need to accurately assess the intravascular fluid volume or the response to blood pressure interventions.
50
When should you use a CVP?
Used in any case when there is the need to closely monitor the intravascular volume status or there is a need to evaluate right ventricular function.
51
When should you use an a-line?
o Used in any case where wide swings in blood pressure are expected, where tight control of blood pressure is needed, in cardiopulmonary bypass cases, or when there will be the need for multiple blood gas analyses.
52
When should you do a TEE?
Used to evaluate regional wall motion abnormalities indicative of myocardial ischemia, to evaluate stroke volume/ejection fraction, to evaluate cardiac valvular function, to look for intracardiac air, to monitor changes in cardiac function, or to evaluate adequacy of intravascular fluid volume.
53
What is the FRC in a normal person?
3L
54
What is the purpose of pre-oxygenation?
To replace nitrogen with oxygen in FRC, giving 3-6min extra of apnea
55
With 4 twitches and spontaneous breathing, the patient may still have ___% of NMJ-R blocked
75% of the NMJ receptors occupied by the blocking agent.
56
How can you test recovery from NMJ blockade?
ability of the patient to maintain a head lift, leg lift or handgrip strength for > 5 seconds.
57
When is the patient ready to extubate?
1. adequately recovered from the effects of the neuromuscular blocking agents
2. is able to breathe on his own
3. is able to follow commands
4. demonstrates purposeful movements
5. can protect his airway
58
What physiological parameters are used to assess readiness for extubation?
* RR > 8 & 5 cc/kg
* TV/RR > 10
* PaO2 > 65-70 mmHg on FiO2
59
All inhalational agents are broncho_____, except for _____ which can precipitate _____
Dilators; desflurane; bronchospasm
60
Inhaled anesthetics ___ TV and ____ RR
Decrease; increase
61
Inhalational anesthetics are eliminated by ____ except for _____
Ventilation; halothane
62
T/F: Nitrous can trigger MH
False
63
Halothane: Pros
Cheap, nonirritating so can be used for inhalation induction
64
Halothane: Cons
Long time to onset/offset, Significant Myocardial Depression, Sensitizes myocardium to catecholamines, Association with Hepatitis
65
Isoflurane: Pros
Cheap, excellent renal, hepatic, coronary, and cerebral blood flow preservation
66
Isoflurane: Cons
Long time to onset/offset, irritating so cannot be used for inhalation induction
67
Desflurane: Pros
Extremely rapid onset/offset
68
Desflurane: Cons
Expensive, Stimulates catecholamine release, Possibly increases postoperative nausea and vomiting, Requires special active-temperature controlled vaporizer due to high vapor pressure, Irritating so cannot be used for inhalation induction
69
Sevoflurane: Pros
nonirritating so can be used for inhalation induction. Extremely rapid onset/offset.
70
Sevoflurane: Cons
Expensive. Due to risk of “compound A” exposure must be used at flows > 2 L/min. Theoretical potential for renal toxicity from inorganic fluoride metabolites.
71
Nitrous: Pros
Decreases volatile anesthetic requirement, Dirt cheap, Less myocardial depression than volatile agents
72
Nitrous: Cons
Diffuses freely into gas filled spaces (bowel, pneumothorax, middle ear, eye, Decreases Fi02, Increases pulmonary vascular resistance
73
What drug is preferred for neurosurgery cases, and why?
Thiopental: decrease ICP by decrease in cerebral oxygen consumption.
74
Thiopental: Cons
Myocardial depression, Vasodilation, Histamine release, Can precipitate porphyria in susceptible patients
75
What is the induction dose of propofol in adults?
1.5 to 2.5 mg/kg
76
What is the maintenance dose of propofol in adults?
100 to 200 micrograms/kg/min
77
What is the induction dose of propofol in kids?
2.5 to 3.5 mg/kg over 20 to 30 seconds
78
What is the maintenance dose of propofol in kids?
125 to 300 mcg/kg/min.
79
What are the cons of etomidate?
Pain on injection, Adrenal suppression (? significance if used only for induction), Myoclonus, Nausea/Vomiting
80
Induction dose of ketamine in adults?
Induction dose of 1 to 2 mg/kg in adults.
81
Dosing of dexmedetomidine?
It is generally given as a loading dose of 0.5-1 mcg/kg over 10 minutes, followed by an infusion of 0.2 to 0.7 mcg/kg/hr.
82
Dosing of midazolam?
Midazolam (Versed) induction dose of 0.1 to 0.2 mg/kg and infusion rates of 0.25 to 1 microgram/kg per minute.
83
How are ester local anesthetics metabolized?
plasma esterases
84
What does metabolism of ester local anesthetics produce?
PABA (allergen)
85
How many "i"s are in the name of an ester anesthetic?
1
86
How are amide local anesthetics metabolized?
Metabolized by hepatic enzymes.
87
How many "is" are in the name of an amide anesthetic?
2
88
Who should avoid morphine?
Renal patients - long acting & renally excreted → active metabolite has opiate properties, therefore beware in renal failure
89
Who should avoid meperidine?
Someone on MAO-Is, cardiac patients, and renal disease
90
Sufentanil is ____x potency of morphine
1000
91
Who should avoid succinylcholine?
MH, hyperK, burns, crush injury, spinal cord injury, muscular dystrophy or disuse syndromes
92
Characteristics of pancurionium?
Slow onset, long duration, tachycardia due to vagolytic effect
93
Characteristics of cisatracurium?
Slow onset, intermediate duration, Hoffman (nonenzymatic) elimination so attractive choice in liver/renal disease.
94
Characteristics of rocuronium?
Fastest onset of nondepolarizers making it useful for rapid sequence induction, intermediate duration.
95
What are MACs of major anesthetics?
```
Nitrous - 104
Desflurane - 6
Sevo - 2.2
Iso - 1.5
Halo - 0.8
```
96
In general, high MAC implies...
Fast onset, low potency
97
Allowable blood loss equation
ABL = BV x (Hcts - Hct-t)/(Hct/s)
```
Hcts = starting Hct
Hct-t = threshold Hct for transfusion
BV = 50cc/kg for F, 60cc/kg for M, 80cc/kg infants, 90cc/kg neonates
```
98
Shortcut for 4-2-1 rule for IVF calculation
40 + weight in kg for anyone over 20kg
99
Fluid deficit
NPO time x maintenance
100
EBL replacement
1: 1 colloid
3: 1 crystalloid
101
When does infarction risk stabilize post-MI?
Infarction risk stabilizes at 5-6% after 6 months
102
What is the periop MI mortality rate?
mortality 20-50%
103
If no prior MI, what is perioperative risk of MI?
0.13%
104
What are strict C/I to surgery?
MI
105
Sx of MH?
increased HR, increased breath rate, increased etCO2 (most sensitive), unstable BP, cyanosis, coca-cola colored urine
106
Confirming dx of MH?
Confirm diagnosis by large difference between venous CO2 and arterial CO2
107
Labs of MH?
Respiratory and metabolic acidosis, hypoxia, hyperkalemia, hypercalcemia, high myoglobin, high CPK, myoglobinuria
108
Tx of MH? (10 steps)
1 - Call for help
2 - Stop volatile anesthetic
3 – 100% O2
4 – Manually hyperventilate
5 – Switch to a clean breathing circuit
6 – Stop surgery, maintain on sedative-hypnotic anesthesia
7 – Dantrolene 2.5mg/kg (mixed with sterile water) q 10 minutes to max dose of 10mg/kg. Maintenance dose at 1mg/kg q 6hrs for 72 hours.
8 – Correct metabolic acidosis with NaCHO3 1-2mg/kg, Correct high K+
9 – Cool patient with iced IV NS, and cold fluids in gastric lavage, in peritoneal or thoracic cavity if open, and PR
10 – Maintain urine output with mannitol or lasix. Do not use CCB’
109
Mechanism of local anesthetics
decrease permeability to Na ions, binds to Na channel in inactivated state, no threshold potential reached, affects rapid firing nerves first, myelinated >>> unmyelinated
110
C/I to local?
hypersensitivity, severe heart block, WPW syndrome
111
Toxicity signs of local?
* Cardio – decreased phase IV depolarization, increased PR, wide QRS
* Pulmonary – phrenic/intercostal nerve paralysis
* CNS – dizziness, circumoral numbness, tinnitus, blurred vision, excitatory signs → CNS depression
* Muscle – toxic injected IM
* Lidocaine known to decrease coagulation
112
What is Mendelssohn’s Syndrome?
o Aspiration pneumonia secondary to aspiration of gastric contents
113
S/Sx of aspiration PNA?
dyspnea, tachypnea, increased HR, wheezing, CXR with lower lobe infiltrates, hypoxia
114
Essential pre-op room check
Suction Airway Machine Pharmacy Monitors
