Principles of Anesthesia Quiz #1 Flashcards
1
Q
What is the blood pressure goal for cardiac patients in OR regarding baseline vitals and blood pressure?
A
Goal is to stay within 10-20% of ischemic free range of baseline pressure
2
Q
Which heart implant will indicate to you that you have a very sick ventricle?
A
AICD, do not over load patient with fluid.
3
Q
When should a new MI case be cancelled with an elective procedure
A
Postpone elective non-cardiac procedures if MI < 1 month prior to procedure Wait 6 months after MI
4
Q
List high risk cardiac surgical procedures
A
Emergent Procedures
Aortic/vascular procedures
Peripheral vascular
Prolonged procedures with blood loss/fluid shifts
5
Q
List intermediate risk cardiac surgical procedure
A
Carotid endarterectomy
Head/neck procedures
intraperitoneal
intrathoracic
6
Q
List low risk cardiac surgical procedures
A
Superficial
cataract
Breast
Endoscopic
7
Q
List the two most important perioperative cardiac risk factors
A
Urgency of procedure (complications 2 to 5 times more likely) Operative site (major thoracic, abdominal, vascular)
8
Q
Intraoperative hypotension can be related to what day of surgery drug?
A
ACEI
9
Q
Possible cancellation of procedure if DBP > ___ with evidence of ___
A
110, organ damage
10
Q
Changes in retinal vasculature ___ the severity and progression of arteriosclerosis and hypertensive damage in other organs
A
parallel
11
Q
What is normal ejection fraction?
A
65%
12
Q
List the two main coronary arteries
A
LMCA (left ventricle) and RCA (SA node, AV node, PDA)
13
Q
MR AS Systolic
A
Sound is restricted forward flow
14
Q
MS AR Diastolic
A
Sound is unrestricted backward flow
15
Q
What is the conduction rate of the SA node
A
100-110
16
Q
Vagal tone brings the resting heart rate to about ___. Located in the junction of the ___ and ___.
A
60-80 bpm, RA, SVC
17
Q
What carries electrical impulses to the LA
A
Bachmann’s Bundle
18
Q
What is the intrinsic rate of the AV node
A
40-60 bpm
19
Q
For leads I, V1, and V6, name differences in left and right bundle blocks.
A
Lead I - left rabbit ear, right biphasic
Lead V1 - left downward, right rabbit
Lead V6 - left upward, right biphasic
20
Q
What has the fastest conduction velocities in the heart?
A
Purkinje Fibers
21
Q
List responses of the sympathetic nervous system
A
Acceleratory response Norepinephrine Increase heart rate Increase force of contraction Increase conductivity Peripheral vasoconstriction Innervates all chambers of heart
22
Q
List parasympathetic responses
A
Inhibitory response Acetylcholine Decreased heart rate Mild decrease in force of contraction Slows conduction through AVN Fibers exist in atria and ventricles (pronounced effects on atria, minimal effects on ventricles)
23
Q
What is the equation of Coronary Vessel Perfusion
A
CPP = DBP - PAWP
Greatest during diastole when ventricle is relaxed, the wall is slightly softer, and blood flow is generous
24
Q
What drug relaxes the heart wall allowing increased blood flow?
A
Nitro
25
What actions supply the heart?
```
Heart rate
Perfusion pressure
O2 content
LVEDP
CAD
O2 extraction
```
26
What are the demands of the heart?
```
Heart rate
Cardiac output
PCWP (LAP)
Systolic blood pressure
Preload/Afterload/Contractility
```
27
Discuss the increase in heart rate and coronary perfusion
As heart rate increases, there is less time for coronary blood flow and perfusion. Systolic contraction pressures also occlude blood flow by applying pressure (10mmHg to 120mmHg). The subendocardium of the LV is most vulnerable.
28
___ is the biggest indicator of CAD.
Unstable angina. Poorly controlled by medications at this point, and carries a significant risk of MI
29
When damage to the heart's endothemlium occurs, it produces less ___ and less ___
NO, Prostacyclin
30
"Critical stenosis" is a ___ decrease in diameter of a large distributing artery.
75%
31
What are goals for treatment of CAD
Restore normal coronary perfusion
Normalize O2 supply/demand ratio
Stent/CABG/Interventions
Antianginals/BB/CCB/Nitrodilators
32
What are pharmacological treatments for stable angina pectoris
Aspirin, plavix, beta blockers, CCB, nitrates, ACEI, risk reduction
33
Define unstable angina
Rest angina >20 minutes, often due to acute event i.e. rupture of small plaque
34
Ischemic heart disease, discuss
caused by supply/demand imbalance
Unstable angina - No damage or biomarker release
Non STEMI - Positive necrosis and biomarker release
STEMI - Biomarker release and ST changes
35
Discuss the four laboratory biomarkers for myocardial infarction (injury)
CK - simple, fast, skeletal muscle not specific to myocardial injury
CK-MB - Cardiac muscle, 3-4 hours post injury, peaks 24 hr, normal 36hr
Troponins - Gold standard, 3-12 hr post MI, elevated 5-10 days for trop I, 2 wks for trop II
BNP - heart failure marker
36
Insufficient blood supply to the myocardium results in:
Ischemia
Injury
Infarct
Depends on length of time blood supply is inefficient, degree of insufficiency, availability of collateral circulation
37
Ischemia increased by ___% in patients whose heart rate is >99 bpm preop
40
38
Most ischemic episodes are r/t ___
Hemodynamic instability
39
What medications do you avoid with ischemia?
Inotropes - increased contractility = increased demand = ischemia
40
What identifies ischemia intraoperatively?
ST segment depression of greater than 1 mm provides evidence of ischemia
41
List interventions for myocardial ischemia
```
Anesthesia
Nitrates
Beta blockers
Calcium channel blockers
Increased perfusion pressure
Positive inotropes
Initiate CPB, cardioplegia for protection, revascularize
IABP
```
42
75% of myocardial injury is caused by ___
Occlusive intracoronary thrombus
43
With MI, how does the Q wave change?
Q wave 0.04 seconds wide. ST segment elevation indicates acute injury.
44
What are the interventions for MI
Minimizing demand and optimizing supply
Heart basal O2 consumption: 8-10ml O2/100g/minute
***The most important factor and primary determinant of myocardial O2 consumption is Heart Rate
Slow heart rate
45
Nitroglycerin, discuss
Acts as substrate for formation of NO
Dilates veins>arteries (peripheral and coronaries)
**Relaxes wall tension - increased blood flow through subendocardium
46
Sodium Nitroprusside (Nipride)
Not for AS/hypotension/hypovolemia
Decreases BP
Decreases SVR
47
Contraindications for beta blockers
```
Contraindications for beta blockers Marked 1st degree AVB
2nd or 3rd degree AVB
Asthma COPD
LV dysfunction
HR < 50 bpm
hypotension
```
48
Effects of beta blockers on supply
Increased diastolic filling time
| increased myocardial flow redistribution (epicardial to endocardial)
49
Effects of beta blockers on demand
Decreased heart rate
Decreased contractility
Decreased systolic wall tension
50
Calcium channel blockers
causes coronary artery dilation in normal and constricted coronaries
Anti-coronary artery spasm properties
Nifedipine, Verapamil, Diltiazem
51
When to use calcium channel blockers?
Helpful for ischemia disease
- decreases MVO2
- decreased inotropy
- relieves ischemia
52
Contraindications for calcium channel blockers
```
EF < 30%
SBP < 90 mmHg
SSS
2nd or 3rd degree AVB
Atrial fib/flutter
```
53
Effects of calcium channel blockers on supply
decreased coronary vascular resistance
decreased heart rate
decreased wall tension
54
Effects of calcium channel blockers on demand
decreased heart rate
decreased contractility
decreased wall tension
55
What is the most sensitive lead to detect ischemia?
Lead 5
56
All agents are safe to use if pacemaker is ___ weeks old
All agents are safe to use if pacemaker is ___ weeks old >2
57
No N2O if ___ days old. Expands pocket, and may displace anode.
<2
58
Avoid ___ for fasiculations and K increase
succinylcholine
59
Aortic stenosis, where is murmur
Systolic murmur best heard in 2nd right intercostal space with transmission into the neck
60
Aortic stenosis
Narrowed pulse pressure
Small or absent dicrotic notch
Exaggerated A and V waves
Harsh low pitched murmur
61
Causes of aortic stenosis
Rheumatic disease
Senile calcification
Congenital malformations
- bicuspid AV is most common
62
What is the aortic stenosis triad of symptoms
Angina pectoris
- usually the first symptom
Syncope
CHF
63
Pathophysiology of aortic stenosis
Chronic pressure overload of LV d/t fixed mechanical obstruction (tight aortic valve)
64
Natural progression of aortic stenosis
Normal AV opening ~3cm
Mild AS >1cm
Moderate AS 0.7-0.9 cm
Severe/critical AS 0.5-0.7 cm
65
Hemodynamic goals in aortic stenosis
Maintain preload - volume dependent (easy with NTG)
NSR with HR 50-70
High afterload - coronary perfusion (early Neo)
Maintain constant contractility - judicious use of BB
66
Anesthetic techniques with aortic stenosis
AS patients will drop their BP badly and quickly
Avoid tachycardia, disastrous, can't tolerate, precipitates ischemia
Normal atrial kick - 25%, AS atrial kick - 40%
67
Rheumatic Heart Disease
```
Rheumatic Heart Disease
d/t Rheumatic fever
Streptococcal infection
Initial pancarditis (inflammation of all layers of heart)
Resolves in weeks
Permanent heart valve damage
MV and AV often damaged
```
68
Signs of good LV
```
No history of s/s of CHF
Hypertension
Normal Cl and LVEDP
Echo WNL
EF >40%
```
69
Signs of poor LV
```
S/S CHF with SOB
Recent/multiple MI
Low Cl, High LVEDP
Abnormal Echo
EF < 40%
```
70
What is protected left main disease
At least one functional graft to either the LAD or Circumflex
Can sometimes intervene safely in CVL
71
What is unprotected Left Main Disease
No graft supplying area distal to lesion at left heart
| Accepted treatment = CABG
72
Patient's requiring higher perfusion pressures
```
Acute infract from CVL
Acute MI
Renal/cerebral insufficiency
Left main/left main equivalent
Aortic Stenosis
Chronic hypertension
```
73
Cardiac catheterization
Gold standard for diagnosis of cardiac pathology
74
Benzos and receptors occupied
<20% - anxiolysis
30-50% - sedation
60 or more - unconciousness
75
Etomidate
Maintains best CV stability
| Stable BP
76
Ketamine
Generalized CV stimulation
| Avoid in patient with CAD, CHF, aneurysms
77
The most important cellular components of vessel walls are ___ and ___
Endothelium and vascular smooth muscle
78
What are some high-risk vascular surgical procedures?
Open aortic aneurysm repair
| Lower extremity revascularization
79
What are some intermediate-risk vascular surgical procedures?
Carotid endarterectomy
| Endovascular aortic aneurysm repair
80
What is the gold standard for carotid revascularization?
Carotid Endarterectomy (CEA)
81
What is the most common cause of morbidity/mortality associated with CEA?
Myocardial ischemia
82
What is the 2nd most common cause of morbidity/mortality associated with CEA?
Stroke
83
What much of the brain's blood supply is supported by the carotids? Vertebrals?
Carotids supply 80-90%
| Vertebrals supply 10-20%
84
What is the most common site of atherosclerosis leading to TIA or stroke?
Carotid bifurcation (origin of the internal carotid artery)
85
List indications for CEA
TIA's associated with ipsilateral severe carotid stenosis (>70%)
Severe ipsilateral stenosis in patient with incomplete stroke
30-70% occlusion in patient with ipsilateral symptoms
Asymptomatic significantly stenotic lesions (>60%)
86
Contraindications for CEA
Acute profound strokes
Progressing strokes
Severe intracranial disease
Other severe generalized disorders (cancer)
87
What are the advantages of using regional anesthesia for CEA?
Awake patient provides sensitive and specific monitor of cerebral perfusion, better than EEG can
88
What will cancel your CEA case?
Uncontrolled HTN, DM, or CAD
89
What is the goal of anesthesia for CEA?
```
To maintain adequate cerebral perfusion without stressing the heart
Avoid tachycardia (esmolol)
No Nitrous oxide
No glucose in IVF
ETT taped to contralateral side
Use Iso
```
90
No monitoring is as effective as what?
An awake patient
91
Stump pressure, What are you measuring when you clamp?
Mean arterial pressure cephalad to cross clamp.
Generated by back pressure from circle of willis
>60 mmHg is adequate
92
Expect profound ___ with manipulation of carotid baroreceptor
bradycardia
| Protamine can drop pressure
93
What is at greatest risk for injury due to aortic cross clamping?
Kidneys
94
Describe an aneurysm
Enlargement of artery twice normal size
| Aortic resection - elective if >4cm
95
What is a common complaint of aortic aneurysms
Intense back and upper abdominal pain
96
What are three types of classifications of aortic aneurysms
DeBakey - Types 1-3 (type 2 is confined to the ascending aorta)
Standford - Types A or B
Crawford - Types 1-4
97
What is an indication for an aortic dissection?
Sharp pain in chest, neck, or between shoulders indicates dissection
98
During cross clamp of descending aorta, where is the blood pressure monitoring performed?
Right radial and left femoral artery, allows for cerebral perfusion and kidney pressures.
99
What do you want to keep your blood pressure at while an aortic clamp is being performed?
MAP around 100 mmHg in upper body, above 50 mmHg distal to clamp
100
How do you calculate spinal cord perfusion pressure?
MAP - CSF = SCPP
101
Cross clamping of ___ aorta decreases renal blood flow significantly
infrarenal
102
List three drugs used in renal protection
Mannitol
Dopamine
Fenoldopam
103
Mesenteric traction may release ___ and cause hypotension
prostacyclin
