Cardiac Pathophysiology Week 2 Flashcards
(105 cards)
1
Q
What are 7 pathologies that are filling problems?
A
- Diastolic HF
- Restrictive Cardiomyopathy
- Cardiac Tamponade
- Constrictive Pericarditis
- Restrictive Pericarditis
- Tricuspid Valve Stenosis (RV filling problem)
- Mitral Valve Stenosis
(LV filling problem)
2
Q
What are 5 pathologies that are emptying problems?
A
- Systolic HF
- Left sided HF
- Dilated Cardiomyopathy
- Pulmonic Valve Stenosis (RV emptying problem)
- Aortic Valve Stenosis (LV emptying problem) - concentric remodeling
3
Q
What are the 2 pathologies that are filling AND emptying problems?
A
- Low-output HF
2. Hypertrophic Cardiomyopathy
4
Q
What 4 pathologies are volume overload issues?
A
- Systolic HF
- Tricuspid Valve regurgitation
- Mitral Valve Regurgitation
- Aortic Valve Regurgitation
5
Q
What 3 pathologies are pressure overload pathologies?
A
- Aortic Stenosis
- Pulmonary HTN
- Systemic HTN
6
Q
What 4 pathologies are contracting problems?
A
- Angina
- Unstable Angina
- NSTEMI
- STEMI
7
Q
During muscle contraction, ATP is required to ____ crossbridges.
A
Break
8
Q
Mechanism of myocardial contraction. 5 steps.
A
Myosin is bound to actin
- ATP binds to myosin → energy released → bond broken
- Myosin now ‘cocked” and ready to go
- Actin binding site is exposed & “cocked” myosin binds
- Conformational change in myosin = “powerstroke”
- Actin filament is moved along myosin
9
Q
ATP use is proportional to ____?
A
MVO2
10
Q
What are 5 factors that modulate MVO2?
A
1 is CARDIOMYOCYTE CONTRACTION
- Preload; optimization of tension formation
- HR; the more contractile events per minute ↑MVO2
- Inotropy; increased Ca2+ release & sensitivity = more cross bridges formed at a faster rate = ↑MVO2
- Afterload
CO is WORK
11
Q
What are 3 factors that can impact afterload?
A
- ↑ LV pressure = ↑ afterload
- ↑ Chamber radius = ↑ afterload
- ↑ ventricular wall thickness = ↓ afterload
12
Q
How does afterload impact the velocity of contraction or BP?
A
↑ afterload = ↓ velocity of contraction = ↓ time for systole = ↓ volume ejected (SV) = ↓BP
13
Q
How does concentric hypertrophy impact afterload?
A
↑ wall thickening = ↓ afterload
14
Q
How does eccentric hypertrophy impact afterload?
A
↑radius / dilation of ventricle = ↑ afterload
15
Q
How does aortic stenosis impact afterload?
A
requires ↑ ventricular pressure = ↑↑afterload
16
Q
How does LVOT obstruction impact afterload
A
requires ↑ ventricular pressure = ↑ afterload
17
Q
What are 4 ways the CRNA can reduce MVO2?
A
- Prevent HR increase (aka SNS activation)
- Prevent ↑ inotropy (via SNS, Ca2+, Ca2+ sensitivity
- Prevent ↑ afterload
- Prevent ↑ preload (too high)
18
Q
MVO2 is increased by what 4 factors?
A
- Afterload
- HR
- Inotropy
- Preload
19
Q
How does ischemic heart disease impact MVO2?
A
↑↑ risk for ischemic event
**make coronary blood flow PRIORITY in the anesthetic plan.
20
Q
Coronary blood flow is how much of the cardiac output?
A
5%
21
Q
What is the O2 extraction in the coronary arteries?
A
70-80%
22
Q
CorrPP = ???
A
(ADBP - LVEDP) / resistance
23
Q
How does HR effect coronary blood flow?
A
“DOUBLE WHAMMY”
- less diastolic time
- increased O2 demand
24
Q
What 5 factors impact coronary artery resistance?
A
- cardiac work output
- extravascular compressive forces
- Neurohumoral & endothelial factors
- Blood O2 content impacts cardiac work & metabolic demand of the heart.
- **MYOCARDIAL METABOLISM IS THE PREDOMINANT DETERMINANT OF CORONARY VASOMOTOR TONE
25
4 components of the Neurohumoral regulation of coronary VSMC tone
1. #1 = metabolic autoregulation
2. SNS / PSNS (minor role)
3. Shear forces; dilation
4. Intraluminal pressure ; constriction
26
What are the 2 categories of coronary artery disease?
1. atherosclerotic
| 2. non-atherosclerotic
27
4 pathologies / results of coronary artery disease
- Angina
- Unstable angina
- NSTEMI
- STEMI
28
3 pathologies of Acute Coronary Syndrome
- Unstable angina
- NSTEMI
- STEMI
29
Acute coronary syndromes cause considerate ___ & ___
considerable immediate morbidity & mortality
HIGH risk of additional injury in the next ONE YEAR
30
CK-MB
creatine kinase, myocardial bound isoenzyme
31
For angina to be stable it must be unchanged for ___
> 2 months
32
Clinical manifestations of stable angina
minimal pain, unchanged for >2 months,
possible EKG changes, ST depression, or T-wave inversion
33
S/S of stable angina
chest pain DURING exertion, pressure, heaviness
-may or may not radiate to arm, shoulder, jaw, neck
epigastric pain
34
S/S of unstable angina
chest pain w/ or w/o exertion
NO cardiac enzymes present in the blood
EKG changes, ST depression or T-wave inversion
35
Pathological causes of angina
- atherosclerosis
- inflammation
- non-occlusive thrombus
- vasospasm
36
Anesthetic GOAL in patient with angina
decrease MVO2
| prevent ischemic event while maintaining CO & BP
37
6 medications or classes to consider giving for angina
1. O2
2. analgesia
3. Beta blocker
4. Ca channel blocker
5. sublingual NO
6. anticoagulation
38
How long does anticoagulation last if a drug-eluding stent is placed?
1 year
39
How long does anticoagulation last if bare metal stent is placed?
6 weeks
40
If a patient has angina, what 3 things should be avoided in the OR?
1. medications that ↑HR and/or BP
2. triggering the SNS response
3. Hypotension [be careful with regional d/t ↓SVR = hypotension]
41
In LV heart failure, what anesthetic should be avoided?
inhaled anesthetics
42
What volatile anesthetic can cause BAD steal effect in the coronary arteries?
Isoflurane
43
What are 4 post-op considerations for a patient with angina?
1. AVOID ISCHEMIA
2. monitor for ischemia
3. treat ischemia
4. avoid sustained hemodynamic changes
44
Causes of NSTEMI
partial blockage of an artery by thrombus, plaque
45
Clinical manifestations of NSTEMI
chest pain; may or may not radiate
*elderly may not have pain
anxious, pale, diaphoretic, tachy, hypotension, dyspnea, nausea, vomiting, dizziness, sudden weakness, fatigue
46
When will cardiac enzymes be present in the blood?
NSTEMI & STEMI
47
What are 2 main cardiac enzymes?
cTroponin
| CK-MB
48
What is different in STEMI vs. NSTEMI
STEMI is 100% block (full thickness ischemia)
| NSTEMI is <100% block
49
An ischemic event is NOT an MI if:
troponin is not elevated
50
Clinical manifestations of STEMI (4)
1. physical s/s
2. significant ST elevation on EKG
3. cardiac enzymes present
4. myocardial ischemia
51
Warning sign for STEMI and what does it indicate?
*worsening angina*
| 2/3 of patients had MI within 30d of worsening angina
52
Anesthetic Implications of STEMI
1. give thrombolytic
| * bleeding risk ↑ with history of GI bleed, surgery, intracranial hemorrhage, >75 years old
53
When does a perioperative MI occur?
within 24-48 hours after surgery
54
What factors increase the risk of a perioperative MI?
Hx ischemic heart disease
emergency surgery
highly vascular surgery
55
what is the mortality of perioperative MI?
20%
56
What is a perioperative MI preceded by?
Tachycardia & ST depression
57
Most perioperative MIs are what kind?
NSTEMI
58
Why is diagnosis of a perioperative MI difficult?
- post-op hemodynamic instability is common
- post-op analgesia may mask chest pain
- ECG changes alone are not diagnostic
- Cardiac enzyme levels are not indicative of duration of ischemia
59
Percutaneous Cardiac Intervention (PCI) is AKA
angioplasty
60
How long should a patient wait after PCI to have surgery?
90 days
61
What are anesthetic considerations of PCI?
```
if PCI was recent, patient likely on anti-platelet therapy
- weigh bleeding risk vs thrombus
monitor closely for MI or infarct
- continuous ECG w/ST analysis
- TEE for ventricular wall function
```
62
What is intraoperative hypotension?
SBP <90mmHg
63
What are 5 causes of intraoperative hypotension?
1. drug side effects (sympatholytic)
2. decreased stimulation
3. Neuraxial anesthesia (↓SNS = ↓SVR = hypotension, bradycardia)
4. MI / congestive HF
5. HTN patients are at much higher risk of intraoperative hypotension
64
Clinical implications of a ↓DBP
- ↓coronary artery perfusion = cardiac ischemia or infarct
- ↓ cerebral perfusion
- ASSOCIATED WITH ANESTHESIA RELATED DEATH
65
patients with uncontrolled HTN at baseline may develop hypotensive effects, when?
at a "normal" BP
66
What are 5 mechanisms that cause ↓DBP?
1. Arterial vasodilation
2. myocardial depression
3. venodilation
4. bradycardia
5. decreased volume (↓F/S)
67
What are the CV effects/mechanisms of arterial vasodilation? (5)
```
↓SNS
↑metabolites
↓SVR
↓CO
↓BP
```
68
What are the CV effects/mechanisms of myocardial depression?
```
drugs
↓SNS
↓inotropy
↓SVR
↓CO
↓BP
```
69
What are the CV effects/mechanisms of venodilation?
↓VR
↓SV
↓CO
↓BP
70
What are the CV effects of bradycardia?
↓HR
↓CP
↓BP
71
Treatments for intra-operative Hypotension
- modest fluid loading
- smaller initial drug dose
- re-introduce RAAS (hold ACEi / ARBs)
- monitor for intraop MI
- Small doses of short acting vasoactive meds
- small short acting vasoactive gtt
72
What is considered acute post-op hypotension?
SBP <90
MAP <65
OR >20% drop from baseline
73
What are causes of acute post-op hypotension?
- administration of anti-hypertensive meds
- inadequate fluid replacement
- blood loss
- residual anesthetic effects
- allergic rxn
- adrenal insufficiency
- myocardial ischemia / CHF
74
What is considered perioperative hypertension?
USA BP > 130/80
| Europe BP >140/90
75
Clinical implications of hypertension?
- leads to 57% of stroke deaths
- 24% of CVD deaths
- BP lability
- High risk of hypotension INTRA-OP
- High risk of HTN POST-OP
*even short duration of MAP <65 mmHg can have deleterious effects = increased mortality, AKI, MI, Stroke
76
Goal when a patient has Hx HTN
maintain BP within 20% of baseline & keep MAP >65mmHg
77
treatment of HTN
vasoactive medications; short acting, monitor frequently, do not overdose
78
Patients that are candidates for intra-op arterial BP monitoring
CAD
cerebral ischemic disease
bleeding and/or fluid shifts
79
Goal when caring for a patient with HTN
prevent end organ damage
80
Proceed with surgery if a patient's BP is
DBP <110mmHg
| SBP <180mmHg
81
Factors that can ↑SNS perioperatively
```
anxiety
pain
DL/intubation
surgical stimulation
hypoxemia/hypercarbia
hypervolemia
vasoactive meds [must be short acting and SMALL doses]
```
82
What is isolated systolic hypertension?
SBP >140
| DBP <90 (normal)
83
What causes isolated systolic hypertension?
stiffening of blood vessels; primarily in elderly
Suspect if patient is >65yr old
84
Patients with isolated systolic hypertension are at significantly increased risk of?
(7)
CAD, ischemic heart disease, left ventricular hypertrophy, CVA, perioperative morbidity & mortality
85
In a patient with isolated systolic hypertension, aggressive attempts to lower the SBP may result in
PROFOUND diastolic hypotension & compromised end organ perfusion
86
What is worse, elevated SBP or widening pulse pressure?
widening pulse pressure
87
What are the 2 types of hypertensive crisis?
1. hypertensive urgency
| 2. hypertensive emergency
88
What is hypertensive urgency?
BP >180/120mmHg
89
What are the s/s of hypertensive urgency?
headache, epistaxis, anxiety
90
What is a hypertensive emergency?
BP > 180/120 & EVIDENCE OF END ORGAN DAMAGE
91
Hypertensive emergency is especially dangerous in who?
women about to give birth
92
What pathologies can cause hypertensive emergency? (4)
1. acute coronary syndrome
2. acute decompensating HF
3. acute LV failure with pulmonary edema
4. dissecting aortic aneurysm
5. Pheochromocytoma
93
What are post-op complications of hypertensive emergency?
hemorrhage & increased ICP
94
What are the neurological s/s of hypertensive emergency?
agitation, delirium, stupor, visual disturbances, seizures, stroke, encephalopathy
95
What is the treatment of hypertensive emergency?
1. IV antihypertensive
2. short acting vasodilators (SNP)
3. AVOID precipitous decline to normo-tension, may cause cerebral or coronary ischemia
96
Pheochromocytoma
Adrenal gland chromaffin cell tumor
97
What is released from a pheochromocytoma?
NE > Epi
opposite of normal
98
S/S of pheochromocytoma?
```
Tachycardia
diaphoresis
headache
paroxysmal HTN
hyperglycemia
```
99
What can worsen the catecholamine effects of pheochromocytoma?
anesthesia
100
What medication should you give with pheochromocytoma?
Phentolamine
101
What does phentolamine do?
inhibits A1 receptors = vasodilation
102
What are the 4 pathological outcomes of pheochromocytoma
1. CVH
2. HF
3. arrhythmias
4. MI
103
What do you give pheochromocytoma patients in preop?
PO phenoxybenzamine and/or IV phentolamine
104
What do you give pheochromocytoma patients post-op?
administration of inotropic agents to correct hypotension resulting from catecholamine withdrawal
105
What are the 3 take aways from HTN/Hypotension?
1. hypotension = high risk morbidity & mortality
2. the most at risk patients are HTN patients
3. HTN patients are the lowest risk for HTN emergency
