EQUIPMENT-Hemodynamic monitors Flashcards
(104 cards)
1
Q
What is the ideal length and width of a BP cuff bladder size
A
Length = 80% extremity circumference Width = 40% extremity circumference
2
Q
Where is each of the following measure highest
SBP
DBP
A
SBP = aortic root DBP = dorsalis pedis artery
3
Q
Where is each of the following measures lowest
SBP
DBP
A
SBP = Dorsalis pedis artery DBP = aortic root
4
Q
Where is the pulse pressure widest and narrowest
A
Widest = Dorsalis pedis artery Narrowest = aortic root
5
Q
What does the auscultation method of measuring BP rely on
A
Korotkoff sounds
6
Q
What does the oscillatory method of BP measure
A
As the cuff is released the monitor measure the pressure fluctuation in response to arterial pulsations
7
Q
What is the most accurate measure provided by the oscillatory BP method
A
MAP
It’s measured when the amplitude of the oscillations is greatest
8
Q
How does a BP cuff that is too small or large affect the BP measure
A
Too small = overestimates BP, high BP (requires MORE pressure to occlude artery)
Too large = underestimates BP, low BP (requires less pressure to occlude BP)
9
Q
Describe the relative SBP, DBP, and pulse pressure at the aortic root
A
SBP is the lowest
DBP is the highest
PP is narrowest
10
Q
Describe the relative SBP, DBP and pulse pressure at the dorsalis pedis artery
A
SBP is the highest
DBP is the lowest
PP is widest
11
Q
As BP is measured further from the aorta, what happens to the dicrotic notch
A
It moves further away from the systolic peak
12
Q
What happens to a BP reading in the following positions relative to the heart
Cuff above heart =
Cuff below heart =
A
Cuff above heart = Falsely decreased
Cuff below heart = falsely increased
13
Q
Why is a BP reading affected by position related to the heart
A
Because of hydrostatic pressure
If it is above the heart there is less hydrostatic pressure. If below the heart, more hydrostatic pressure
14
Q
How much can a BP reading change for every 2 inches or 10 cm above or below the heart
A
2 mmHg per inch
7.4 mmHg per 10 cm
15
Q
The BP cuff is 5 inches below the level of the heart. How is the reading affected?
A
It will be 10 mmHg higher, or falsely elevated
16
Q
What do the following morphology of arterial lines assess: Peak waveform = Trough waveform = Peak - trough = Upstroke = Area under curve = Dicrotic notch =
A
Peak waveform = SBP Trough waveform = DBP Peak - trough = PP Upstroke = Contractility Area under curve = Stroke volume Dicrotic notch = Aortic valve closure
17
Q
Where are the following assessed on an arterial line waveform SBP = DBP = Pulse pressure = Contractility = Stroke volume = AV closure =
A
SBP = Peak waveform DBP = Trough waveform Pulse pressure = Peak - trough Contractility = Upstroke Stroke volume = area under the curve AV closure = Dicrotic notch
18
Q
Where is the invasive BP monitor measuring BP
A
At the level of the transducer
19
Q
How does an under-damped system impact BP measure (SBP, DBP, MAP)
A
SBP = overestimated DBP = underestimated MAP = accurate
20
Q
How does an over-damped system impact BP measure (SBP, DBP, MAP)
A
SBP = underestimated DBP = overestimated MAP = accurate
21
Q
What determines an optimally damped arterial monitoring system
A
Return to baseline after 1 oscillation with a square wave test
22
Q
What assessment determines that an arterial line is under-damped
A
Baseline is re-established after SEVERAL oscillations with a square wave test
23
Q
What are causes of an under-damped arterial monitoring system
A
Stiff (non-compliant) tubing Catheter whip (artifact)
24
Q
What assessment determines that an arterial line is over-damped
A
Baseline is re-established with NO oscillations following a square wave test
25
What are 5 causes of an over-damped arterial monitoring system
```
Air bubbles
Clot on catheter
Low flush bag pressure
Kinks
Loose connection
```
26
Where should the tip of a CVC terminate
Junction of the vena cava and RA
27
Where should the tip of a PA catheter reside
In the pulmonary artery, distal to the pulmonic valve
| 25 - 35 cm from VC junction
28
What structure is a risk for injury when access the left IJ
The thoracic duct causing chylothorax
29
What is the most common complication when placing CVC
dysrhythmias
30
What is the classic sign of PA rupture
hemoptysis
31
What are 3 complications of the CVC residing in the cardiac chamber
1. Dysrhythmias
2. Thrombus formation
3. Cardiac perforation
32
```
How far should the CVC be threaded to reach the VC junction from the following sites
Subclavian=
Right IJ=
Left IJ=
Femoral=
```
Subclavian= 10 cm
Right IJ= 15 cm
Left IJ= 20 cm
Femoral= 40 cm
33
What are 5 CVC complications while obtaining access
1. Arterial puncture
2. PTX
3. Air embolism
4. Neuropathy
5. Catheter knot
34
What are 5 CVC complications during catheter residence
1. Infection
2. Myocardial or valvular injury
3. Sepsis
4. Thrombus formation
5. Thrombophlebitis
35
What are 4 PA catheter complications while floating the catheter
1. PA rupture
2. RBBB
3. Complete HB (w/ pre-existing LBBB)
4. Dysrhythmias
36
Why should a PA cath not be floated in a patient with a LBBB
Passing the cath into the RV can cause a RBBB leading to CHB
37
What 3 patient related factors increase the risk of PA rupture
1. Anticoagulation
2. Hypothermia
3. Advanced age
38
What 5 provider factors increase the risk of PA rupture
1. Inserting cath too far
2. Prolonged balloon inflation
3. Chronic irritation of vessel wall
4. Unrecognized wedge
5. Balloon filled with liquid instead of air
39
What does the CVP waveform reflect
The pressure inside the right atrium
40
How many peaks and troughs occur in a CVP waveform
```
3 peaks (a, c, v)
2 troughs (x, y)
```
41
What mechanical event does each point on the CVP waveform represent
A wave = RA contraction
C wave = tricuspid valve elevation into RA (TV closed)
X decent = down movement of contracting RV
V wave = passive RA filling
Y decent = RA empties through tricuspid
42
What is the order of the peaks and troughs of the CVP waveform
```
A wave
C wave
X decent
V waves
Y decent
```
43
Which valves are open and closed during the a wave
```
Open = TV, MV
Closed = PV, AV
```
44
Which valves are open and closed during the c wave
```
Open = NONE
Closed = all valves
```
45
Which valves are open and closed during the x decent
```
Open = PV, AV
Closed = TV, MV
```
46
Which valves are open and closed during the v wave
```
Open = NONE
Closed = all
```
47
Which valves are open and closed during the y decent
```
Open = TV, MV
Closed = PV, AV
```
48
Which part of the CVP waveform correlates with ventricular systole
c wave
| x decent
49
Which part of the CVP waveform correlates with ventricular diastole
v wave
a wave
y decent
50
Which part of the CVP waveform correlates with atrial systole
a wave
51
Which part of the CVP waveform correlates with atrial diastole
c wave
x decent
v wave
y decent
52
Which part of the CVP waveform follows the EKG P wave
a wave
53
Which part of the CVP waveform follows the QRS complex
c wave
| x decent
54
Which part of the CVP waveform follows the EKG T wave
v wave
| y decent
55
The x decent correlates with which event on the EKG
ST segment
56
```
Which electrical events do the following CVP events correlate
a wave=
c wave=
x decent=
v wave=
y decent=
```
```
a wave= after P wave
c wave= after QRS complex
x decent= ST segment
v wave= after T wave begins
y decent= after T wave ends
```
57
How does a CVP transducer above or below the zero point affect the reading
Above = underestimates (LOW)
| Below =overestimates (HIGH)
58
At what point of the respiratory cycle is CVP read and why
End-expiration
| At this point, extravascular pressure equals Patm and the reading isn't affected by intrathoracic pressure
59
CVP is the function of what 3 physiologic factors
1. Intravascular volume
2. Venous tone
3. RV compliance
60
What factors increase CVP
1. Transducer below zero
2. RV failure
3. TV stenosis or regurg
4. Pulmonic stenosis
5. VSD
6. Constrictive pericarditis
7. Cardiac tamponade
8. PEEP
9. Hypervolemia
61
What factors decrease CVP
1. Transducer above zero
| 2. Hypovolemia
62
Normal CVP range
1 - 10 mmHg
63
What can loss of the CVP a-wave indicate
1. a-fib
| 2. V-pacing w/ asystole
64
What can a large CVP a wave indicate (8)
1. Tricuspid stenosis
2. Diastolic dysfxn
3. MI
4. RV hypertrophy
5. AV dissociation
6. Junctional rhythm
7. PVCs
8. Asynchronous V-pacing
65
What can can a large CVP v wave indicate (3)
1. Tricuspid regurg
2. Acute increased volume
3. RV papillary MI
66
What is the morphology of the RVP waveform
| Normal values
Systolic pressure increases
Diastolic = CVP
No dicrotic notch
Normal = (15 - 30)/(0-8)
67
What is the morphology of the PA pressure
| Normal values
Systolic remains the same as RVP
Diastolic rises
Dicrotic notch present d/t pulmonic valve closure
Normal = (15-30)/(5-15)
68
What is the morphology of the PAOP waveform
| Normal values
- Akin to CVP of left heart (similar waveform morphology as RA CVP)
- a wave = LA systole
- c wave = MV closure, LV systole
- v wave = passive LA filling
Normal = 5 - 15
69
What do the events on the PAOP waveform represent
a wave=
c wave=
v wave=
a wave= LA systole
c wave= MV elevation and closure, LV systole
v wave= LA passive filling
70
Which events on the PAOP waveform correspond to the following
LA passive filling =
LV systole =
LA systole =
LA passive filling = v wave
LV systole = c wave
LA systole = a wave
71
For the most accurate LVEDP, where should the PAC tip reside
West Zone 3
| P atrial > P venous > P alveolus
72
Why is west zone 3 the best placement for PA readings
There is a continuous column of blood between the tip of the PAC and the LV (constant reading)
The arterial pressure is always highest
73
3 things that suggest the tip of the PA cath is NOT in zone 3
1. PAOP > PA end-diastolic pressure
2. Nonphasic PAOP tracing
3. Inability to aspirate blood from distal port when balloon is wedged
74
What measure does PAOP reflect
LV-EDP/EDV
75
What 4 cardiac factors can cause PAOP to overestimate LVEDP
1. Impaired LV compliance (ischemia)
2. MV dz (stenosis or regurg)
3. L-to-R cardiac shunt
4. Tachycardia
76
What 5 pulmonary factors cause PAOP to overestimate LVEDP
1. PPV
2. PEEP
3. COPD
4. Pulm HTN
5. Non-West Zone 3 placement
77
What condition causes PAOP to underestimate LV-EDP/EDV
Aortic valve insufficiency
78
How does the area under the curve correlate to CO with the thermodilution measurement method
The AUC is inversely proportional to the CO
79
What 2 factors for measuring CO can underestimate the CO (the CO is really higher)
1. Injectate volume too high
| 2. Injectate solution too cold
80
What 4 factors for measuring CO can overestimate the CO (the CO is really lower)
1. Injectate volume too low
2. Injectate solution too hot
3. Partially wedged PAC
4. Thrombus on PAC tip
81
What 2 conditions are unable to predict accurate CO with thermodilution method
1. Intracardiac shunt
| 2. Tricuspid regurg
82
What 4 variables is mixed venous O2 sat dependent on
1. CO (L/min)
2. O2 consumption (mL O2/min)
3. Hgb (g/dL)
4. Hgb sat (%)
83
What are 2 pathophysiologic factors that decrease SvO2
1. Increased O2 consumption
| 2. Decreased O2 delivery
84
What are 2 pathophysiologic factors that increase SvO2
1. Decreased O2 consumption
| 2. Increased O2 delivery
85
What is the normal SvO2
65 - 75%
86
How does SvO2 reflect CO
When hgb, SaO2, and VO2 are held constant, SvO2 becomes an indirect monitor of CO
87
What 5 conditions decrease SvO2 by increasing O2 consumption
1. Stress
2. Pain
3. Thyroid storm
4. Shivering
5. Fever
88
What 3 factors decrease SvO2 by decreasing O2 delivery
1. Decreased PaO2
2. Decreased Hgb
3. Decreased CO
89
What 2 factors increase SvO2 by decreasing O2 consumption
1. hypothermia
| 2. Cyanide toxicity (Nitropruss)
90
What 3 factors increase SvO2 by increasing O2 delivery
1. Increased PaO2
2. Increased Hgb
3. Increased CO
91
Where is the best place to obtain a sample to measure SvO2
Pulmonary artery
| It is where all blood returning from the body is mixed
92
What is the formula for
SvO2 = SaO2 - [(VO2)/(Q x 1.34 x Hgb x 10)]
93
Describe how pulse pulse contour analysis provides a measure of preload responsiveness
It's a function of how stroke volume changes during the respiratory cycle w/ PPV
Changes in intra-thoracic pressuring during PPV influences stroke volume
94
How does inspiration affect LV filling
Augments
compression of the pulmonary veins and pleural restriction impedes RV filling
Increased LV filling = increases SV
95
How does expiration affect LV filling
It decreases
the decreased RV preload during inspiration reduces LV preload
Decreased LV filling = reduced SV
96
When assessing SVV throughout the respiratory cycle, how do you know a pt requires volume
A greater degree of SVV throughout the respiratory cycle determines that the intrathoracic pressure affects RV filling (indicating hypovolemia)
97
When can preload responsiveness be assumed when assessing SVV
When a 200 - 250 mL bolus improves SVV by >10%
98
What 3 pulmonary factors can limit the assessment of pulse contour analysis
1. Spontaneous ventilation
2. Small Vt
3. PEEP
99
What 3 cardiac factors can limit the assessment of pulse contour analysis
1. Open chest
2. RV dysfunction
3. Dysrhythmias
100
Where is the tip of the esophageal probe positioned
35 cm from incisors
at the T5-T6 level
3rd sternocostal junction
101
What variables does the esophageal doppler measure
1. Peak velocity
2. Flow time
3. Mean acceleration
4. Cycle time
5. Stroke distance
102
```
What do each of the following esophageal doppler variables reflect
Peak velocity=
Flow time=
Flow time corrected=
Mean acceleration=
Cycle time=
Stroke distance=
```
Peak velocity= Contractility
Flow time= Flow time from LV during systole
Flow time corrected= Flow time indexed to HR 60
Mean acceleration= Avg speed on waveform upstroke (cm/sec)
Cycle time= Time of one cardiac cycle
Stroke distance= How far SV is pumped along aorta/beat
103
What 6 factors affect the reliability of esophageal doppler measurement
1. Aortic stenosis
2. Aortic insufficiency
3. Thoracic aorta Dz
4. Aortic x-clamp
5. After CPB
6. Pregnancy
104
What is a contraindication to esophageal doppler use
Esophageal dz (varices)
