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Patient Monitoring/ Instrumentation Kristi > Advanced Hemodynamic Monitoring > Flashcards

Advanced Hemodynamic Monitoring Flashcards

1
Q

normal cardiac index value (CI)

A

2.2-4.2 L/min/m2

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2
Q

normal central venous pressure value

A

5-12 mmHg

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3
Q

CVP is most accurate when measured at the end of (inspiration/expiration)

A

expiration

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4
Q

what position are CVP, PAP, and PWCP readings considered reliable?

A

if the backrest positions are from 0-60 degrees

-not considered as accurate if the patient is truly “sitting”

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5
Q

normal value of coronary perfusion pressure

A

auto regulated between 50-120 mmHg

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6
Q

normal value of mixed venous oxygen saturation (mvO2)

A

60-80% in an awake patient

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7
Q

mixed venous oxygen saturation is roughly equal to what other value?

A

central venous oxygen saturation (ScvO2)

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8
Q

normal value of pulmonary artery pressure

A

15-30
——— mmHg
10

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9
Q

pulmonary artery pressure is not considered “accurate” if the patient is in what position

A

sitting

-same reason as CVP

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10
Q

value of mild pulmonary hypertension

A

36-49 mmHg systolic

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11
Q

value of moderate pulmonary hypertension

A

50-59 mmHg systolic

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12
Q

value of severe pulmonary hypertension

A

> 60 mmHg

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13
Q

normal value of pulmonary capillary wedge pressure (PCWP)

A

less than 12 mmHg

1-4 mmHg less than pulmonary artery diastolic pressure

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14
Q

PCWP is not considered accurate if the patient is in what position?

A

sitting

-same reasons as CVP

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15
Q

normal value for pulmonary vascular resistance (PVR)

A

100-300 dynes:sec:cm-5

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16
Q

normal value for an adult stroke volume

A

60-90 mL/ beat

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17
Q

normal value for stroke volume index

A

20-65 mL/beat/m2

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18
Q

normal values of systemic vascular resistance (SVR)

A

700-1200 dynes:sec:cm-5

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19
Q

normal values of central venous O2 saturation (ScvO2)

A

25-30% below the patients SaO2
OR
70-75% if the SaO2 is normal

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20
Q

which reflex responds to a changes in blood pressure?

A

baroreceptor reflex

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21
Q

where are the baroreceptor reflexes located?

A

inside the carotid sinus (hypoglossal nerve)

and aortic arch (vagus nerve)

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22
Q

Baroreceptor reflex: when the blood pressure is low, the HR (increases/ decreases)

A

increases

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23
Q

Baroreceptor reflex: when the blood pressure is high, the HR (increases/ decreases)

A

decreases

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24
Q

which reflex responds to changes in blood volume inside the heart

A

bainbridge reflex

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25
Q

Bainbridge reflex:
when right atrial pressure increases (blood volume in the right atrium increases), the Bainbridge reflex causes
1. the HR to (increase/decrease)
2. (vasodilation/ vasoconstriction)

A
  1. HR will increase ( in an effort to get the blood out)

2. vasodilation (causes venous pooling in the legs and decreased venous return

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26
Q

BOTH a (high/low) CVP through the baroreceptor reflex and a (high/low) CVP through the Bainbridge reflex will cause an increase in HR

A

low CVP

high CVP

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27
Q

cardiac index allows a more accurate interpretation of cardiac output because the number is not skewed by what patient factor

A

weight

-cardiac index is the same for all patients, regardless of size

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28
Q

cardiac index equation

A

body surface area

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29
Q

stroke volume index equation

A

body surface area

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30
Q

stoke volume index allows a more accurate interpretation of stroke volume because the number is not skewed by which patient factor?

A

weight
-a neonate or morbidly obese patient will have a different stroke volume but the same stroke volume index if they both have normal heart function

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31
Q

3 equations to calculate coronary perfusion pressure

A
  1. CPP=DBP-LVEDP (need to estimate LVEDP from below)
  2. CPP= DBP-CVP
    (diastolic blood pressure-right atrial pressure)
  3. CPP= DBP-PCWP
  4. CPP=DBP-PA diastolic pressure
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32
Q

we can ESTIMATE LVEDP because the blood pressure in the left ventricle at the end of diastole is roughly equal to which other pressure?

A

Left atrial pressure (systolic pressure in the left atrium)

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33
Q

which pressure gives us an estimate of Left atrial pressure

A

PCWP

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34
Q

LVEDP is estimated from what pressure?

A

left atrial pressure

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35
Q

left atrial pressure is estimated from what pressure?

A

PCWP

-wedge pressure can estimate LVEDP and give a way to calculate coronary perfusion pressure

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36
Q

PCWP is estimated from what pressure?

A

PA diastolic pressure

-diastolic pressure in pulmonary artery will almost always equal wedge pressure

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37
Q

2 ways to estimate LVEDP

A
  1. PCWP or pulmonary artery occlusion pressure

2. PA diastolic pressure

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38
Q

in the thermodilution technique how much saline is injected and where is it injected to?

A

10 mL cold saline

right atrium through the CVP port

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39
Q

how fast must the thermodilution injection be?

A

<4 sec

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40
Q

thermodilution technique: the cold saline travels to the _____artery where it encounters the _____ on the swan

A

pulmonary
thermistor
-the cold fluid is warmed to a degree (from normal body heat) before it gets to the thermistor

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41
Q

thermodilution technique: the monitor produces a _____ based on how cold the fluid at the thermistor is

A

waveform

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42
Q

thermodilution technique: if the cardiac output is high, the temperature at the thermistor will get (warm/cold) fast but will (warm/cool) quickly

A

cold

warm

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43
Q

thermodilution technique: if the cardiac output is high, the total area under the thermodilution curve will be (higher/ lower) than normal

A

lower

-the curve is tall and narrow

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44
Q

thermodilution technique: if the cardiac output is low, the temperature at the thermistor will be (warm/cold) for a long period of time

A

cold

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45
Q

thermodilution technique: if the cardiac output is low, the total area under the thermodilution curve will be (lower/ higher) than normal

A

higher

-the curve is short and wide

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46
Q

interpretation of thermodilution waves:

a small wave indicates?

any factor that decreases the area under the curve will (overestimate/underestimate) cardiac output

A

high cardiac output

-any factor that decreases the area under the curve will overestimate cardiac output

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47
Q

interpretation of thermodilution waves:

a large wave indicates?

any factor that increases the area under the curve will (overestimate/underestimate) cardiac output

A

low cardiac output

underestimate

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48
Q

the cardiac output reading is (directly/ inversely) proportional to the area under the thermodilution curve

A

inversely

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49
Q

thermodilution technique:
if the anesthetist injected the saline to slow (>4 seconds), the thermodilution curve would be (smaller/larger) than normal

and the cardiac output reading would be (overestimated/underestimated)

A

larger (the blood at the thermistor would stay colder for longer)

underestimated (give a reading lower than what it really is)

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50
Q

thermodilution question:
a patient has a right to left intracardiac shunt. Would thermodilution in this patient lead to an overestimation or underestimation of cardiac output?

A

overestimation

-some cold fluid is lost to the left side so the blood in the PA will be warmer ( the curve is smaller)

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51
Q

thermodilution question:
A patient has a left to right intracardiac shunt. Would thermodilution in this patient lead to an overestimation or underestimation of cardiac output?

A

Overestimation

-Cold fluid is diluted by warm blood from the left side, so the blood in the PA will be warmer (curve will be smaller)

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52
Q

thermodilution question:
A patient has tricuspid regurgitation. Would thermodilution in this patient lead to an overestimation or underestimation of cardiac output?

A

underestimation

-The blood at the thermistor will stay colder for a longer period (curve will be bigger)

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53
Q

what 2 monitoring alternatives replaced thermodilution

A
  1. Continuous Cardiac Output (CCO) pulmonary artery catheters
    (can estimate cardiac output without the anesthetist injecting saline)
  2. Transesophageal echocardiography (TEE)
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54
Q

name of the oxygen saturation of blood taken from the superior vena cava

A

ScvO2
-since it is proximal to the right atrium, this will not include blood from the coronary sinus (the coronary sinus drains into the inferior part of the right atrium)

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55
Q

how can an ScvO2 sample be drawn?

A

through the central venous line port

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56
Q

name of the oxygen saturation from the superior vena cava, inferior vena cava, and coronary sinus

A

mixed venous O2 saturation

mvO2

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57
Q

where is the mvO2 sample taken?

A

at the distal tip of the pulmonary artery catheter

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58
Q

mvO2 will be slightly (lower/higher) percent O2 saturation than ScvO2

why?

A

lower

the heart burns more oxygen than other organs so the coronary sinus blood is more deoxygenated

59
Q

low cardiac output= (low/high) mvO2/ScvO2

A

low
-with low cardiac output, blood is more deoxygenated by the time the blood gets back to the heart because it traveled more slowly throughout the body and had more time to unload oxygen to tissues

60
Q

high cardiac output= (low/high) mvO2/ScvO2

A

high
-in high cardiac output states, blood is less deoxygenated by the time it returns back to the heart because it traveled faster through the body and had less time to unload oxygen to the tissues

61
Q

list 2 reasons why mvO2 and ScvO2 are rarely used to estimate cardiac output

A
  1. it requires drawing blood from a central line or a swan

2. cardiac output can be measured by other effective methods (CCO swan, TEE, Flotrac sensor)

62
Q

the equation for ohms law

A

V= IR

v= voltage
I= current
R= resistance
63
Q

resistance is equivalent to ____ or ____in the body

A

SVR or PVR

64
Q

current (I) is equivalent to _____ _____ in the body

A

cardiac output

65
Q

voltage (v) is equivalent to the difference in blood pressure at the _____end of the body and the blood pressure at the ____ end of the body

A

arterial (MAP)
venous (CVP)
MAP-CVP

66
Q

So, if we can measure CVP (with a central line) and monitor MAP (with an A-line) and cardiac output (with a Swan), we can CALCULATE _____

A

SVR

67
Q

cardiac output equation from ohm’s law

A 
V= IR
MAP-CVP = CO X SVR
68
Q

what number is used in the cardiac output equation to convert the units used for blood pressure and SVR into the units for cardiac output

A

80

69
Q

MAP=89
CVP=9
CO=4

Calculate SVR

A

(89-9/4) X (80) = 1600

70
Q

BP= 100/80
CVP=3
SVR=900

Calculate cardiac output

A

(87-3/900) X (80) = 7.5

71
Q

Therefore, if we can measure PAP, PCWP, and cardiac output (with a Swan), we can CALCULATE _____

A

PVR

72
Q

pulmonary equation from ohm’s law

A 
V= IR
(PAP-PCWP) = CO X PVR
73
Q 
PAP= 28/10 
PCWP= 6 
CO= 4

What is the PVR?

A

(16-6)/ 4 X (80) = 200

74
Q

PAP = 24/6
PCWP= 4
PVR=150

What is the cardiac output?

A

(12-4)/ 150 X 80= 4.2

75
Q

3 things pulse pressure is affected by

A

stroke volume
systemic vascular resistance
aortic compliance

76
Q

stroke volume is proportional to _____ blood pressure

A

systolic

77
Q

increased stroke volume = ( increased/decreased) systolic pressure

A

increased

78
Q

decreased stroke volume = (increased/decreased) systolic pressure

A

decreased

79
Q

SVR is proportional to _____ blood pressure

A

diastolic

80
Q

increased SVR (vasoconstriction) = (increased/decreased) diastolic BP

A

increased

81
Q

decreased SVR (vasodilation) = (increased/decreased) diastolic BP

A

decreased

82
Q

if the aorta has good compliance, the systolic pressure will be (higher/lower)

A

lower

83
Q

if the aorta has poor compliance (stiff), the systolic pressure will be (higher/lower)

A

higher

84
Q

systolic pressure (pulse pressure) is (directly/ inversely) proportional to aortic compliance

A

inversely

85
Q

A patient is hypovolemic. Should an anesthetist expect a wide or a narrow pulse pressure?

A

Narrow; lower stroke volume and vasoconstriction

86
Q

A patient has congestive heart failure (CHF). Should an anesthetist expect a wide or a narrow pulse pressure?

A

Narrow; also due to low stroke volume and vasoconstriction

87
Q

You just got done running 3 miles on a treadmill. Would you be expected to have a wide or a narrow pulse pressure?

A

Wide; increase stroke volume and vasodilation

88
Q

A patient has cardiac tamponade (blood in the pericardial sac). Should an anesthetist expect a wide or a narrow pulse pressure?

A

Narrow; decrease stoke volume and vasoconstriction

89
Q

A patient has aortic stenosis (narrowing of the aortic valve). Should an anesthetist expect a wide or a narrow pulse pressure?

A

Narrow; decrease stoke volume and vasoconstriction

90
Q

A patient is on a Milrinone drip, which causes an increase in cardiac contractility and a decrease in SVR. Should an anesthetist expect a wide or a narrow pulse pressure?

A

wide

91
Q

A patient has aortic regurge. Should an anesthetist expect a wide or a narrow pulse pressure?

A

Wide; due to lower diastolic volume

92
Q

fluid overload causes high or low CVP

A

high

93
Q

heart failure causes high or low CVP

A

high

94
Q

pulmonary hypertension causes high or low CVP

A

high

95
Q

trendelenburg causes high or low CVP

A

high

96
Q

high intrathoracic pressure (tension pneumothorax) = causes high or low CVP

A

high
-high intrathoracic pressure decreases venous return from the head (in addition to the legs) which causes pooling of blood in the central veins = increased CVP

97
Q

hypovolemia causes high or low CVP

A

low

98
Q

sitting position causes high or low CVP

A

low

99
Q

vasodilation causes low or high SVR

A

low

100
Q

vasoconstriction causes low or high SVR

A

high

101
Q

decreased cardiac contractility causes a low or high cardiac index

A

low

102
Q

bradycardia causes a low or high cardiac index

A

low

103
Q

hypovolemia causes a low or high cardiac index

A

low

104
Q

hypervolemia (if patient has HF) causes a low or high cardiac index

A

low

105
Q

increased afterload (aortic stenosis or high SVR) causes a low or high cardiac index

A

low

106
Q

increased contractility/ stroke volume causes a low or high cardiac index

A

high

107
Q

tachycardia causes a low or high cardiac index

A

high

108
Q

vasodilation causes a low or high cardiac index

A

high

-decreased afterload leads to increased stroke volume (due to the left ventricle pumping against less resistance)

109
Q

how is hypotension due to hypovolemia treated?

A

fluids/blood products

110
Q

how is hypotension due to vasodilation treated?

A

vasopressors

reversing cause of vasodilation (decreasing anesthetic)

111
Q

how is hypotension due to heart failure (decreased contractility) treated?

A
  1. inotropes

2. diuretics (fluid overload can cause decreased contractility)

112
Q

If a patient has hypotension due to hypovolemia, would the anesthetist expect the following to be increased or decreased?

Cardiac index

CVP

SVR

A

Cardiac index= decreased

CVP= decreased

SVR= increased

113
Q

If a patient has hypotension due to vasodilation, would the anesthetist expect the following to be increased or decreased?

Cardiac index

SVR

A

cardiac index= increased

SVR= decreased

114
Q

If a patient has hypotension due to decreased contractility, would the anesthetist expect the following to be increased or decreased?

cardiac index

CVP

SVR

A

cardiac index= decreased

CVP= increased

SVR= increased to maintain normal BP

115
Q

A patient is adequately anesthetized and has a pulmonary artery catheter in place. Monitors show the following values:

HR: 98 bpm
BP: 88/40 mmHg
CVP: 8 mmHg
PAP: 25/8 mmHG
SVR: 400 dynes
PVR: 200 dynes
cardiac index: 3 L/min

Of the following options, which treatment will best normalize the patient’s vital signs?

A. Fluid bolus
B. Vasopressor
C. Inotrope
D. Vasodilator
E. Diuretic
F. Beta blocker
A

B. Vasopressor

116
Q

A patient is adequately anesthetized and has a pulmonary artery catheter in place. Monitors show the following values:

HR: 65 bpm
BP: 85/40 mmHg
CVP: 7 mmHg
PAP: 25/8 mmHg
SVR: 1100 dynes
PVR: 250 dynes
cardiac index: 1.8 L/min

Of the following options, which treatment will best normalize the patient’s vital signs?

A. Fluid bolus
B. Vasopressor
C. Inotrope
D. Vasodilator
E. Diuretic
F. Beta blocker
A

C. inotrope

117
Q

A patient is adequately anesthetized and has a pulmonary artery catheter in place. Monitors show the following values

Heart Rate = 60
bpm
Blood Pressure = 170/105mmHg 
CVP = 7mmHg

PAP = 35/10mmHg

SVR = 1700 dynes·sec·cm–5 
PVR = 350 dynes·sec·cm–5 
Cardiac Index = 2.8L/min/m2

Of the following options, which treatment will best normalize the patient’s vital signs?

A. Fluid bolus
B. Vasopressor
C. Inotrope
D. Vasodilator
E. Diuretic
F. Beta blocker
A

D. vasodilator

118
Q

A patient is adequately anesthetized and has a pulmonary artery catheter in place. Monitors show the following values:

Heart Rate = 100

Blood Pressure = 84/55mmHg 
CVP = 2mmHg

PAP = 20/5mmHg

SVR = 1500 dynes·sec·cm–5 
PVR = 100 dynes·sec·cm–5 
Cardiac Index = 2.0L/min/m2

Of the following options, which treatment will best normalize the patient’s vital signs?

A. Fluid bolus
B. Vasopressor
C. Inotrope
D. Vasodilator
E. Diuretic
F. Beta blocker
A

A. fluid bolus

119
Q

refers to stroke volume and systolic blood pressure fluctuating during inspiration and expiration

A

stroke volume variation (SVV)

- aka “pulse pressure variation”

120
Q

in healthy spontaneously ventilating patients, systolic blood pressure (increases/ decreases) ______ mmHg during inspiration

A

decreases 5-10 mmHg

  1. pulmonary vessels vasodilate during inspiration
  2. the vasodilation causes blood to pool in the lungs
  3. when blood pools in the lungs, less blood is available to pump to the body
  4. this leads to a slight drop in blood pressure during inspiration
121
Q

the term for exaggerated stroke volume variation

A

pulsus paradoxus

122
Q

in healthy mechanically ventilated patients, systolic blood pressure (increases/ decreases) ______ % during inspiration because of lung inflation

A

increases 5-10%

  1. Displaces the left ventricular wall inward during systole, assisting ventricular contraction (increasing ejection fraction)
  2. Squeezes blood out of the pulmonary capillaries and into the left atrium, increasing blood volume and stroke volume during inspiration
123
Q

if stroke volume/systolic blood pressure has wider than expected fluctuations during inspiration and expiration, it is referred to as ______ _______

A

pulsus paradoxus

124
Q

a patient is considered to have pulsus paradoxus if:

  1. their systolic BP (increases/decreases) more than _____mmHg during spontaneous inspiration
  2. their systolic BP (increases/decreases) more than _____% during mechanical inspiration
A
  1. decreases, 10mmHg

2. increases, 10-15%

125
Q

how can pulsus paradoxus be detected?

A

SpO2 and arterial line waveforms

126
Q

what is the most common cause of pulsus paradoxus?

A

hypovolemia

127
Q

2 other circumstances that pulsus paradoxus can be seen

A
  1. cardiac tamponade
  2. tension pneumothorax
    - Less commonly, pulsus paradoxus can be caused by vasodilation, CHF, hypervolemia, and PEEP
128
Q

what is the cardiac tamponade mechanism for pulsus paradoxus

A
  1. during inspiration blood volume in the right ventricle increases
    - normally right ventricle will expand and absorb this pressure
  2. the right ventricular wall cannot expand
    - because of fluid in the pericardial sac
  3. the increase in right ventricular volume/ pressure during inspiration will force the interventricular septum to bulge over to the left
  4. this causes a decrease in the volume of the left ventricle, a decrease in stroke volume, and a greater decrease in blood pressure during inspiration
129
Q

what is the tension pneumothorax mechanism for pulsus paradoxus

A
  1. blood volume in right ventricle increases with inspiration
  2. the right ventricular wall cannot expand
    - because of external compression on the heart from the increased thoracic pressure
  3. increase in right ventricular volume/pressure will force the interventricular septum to bulge over to the left
  4. causes a decrease in volume of the left ventricle, a decrease in stroke volume, and a greater decrease in blood pressure during inspiration
130
Q

stroke volume variation on inspiration of healthy patients during spontaneous ventilation

A

Systolic blood pressure and pulse pressure decrease 5-10mmHg during inspiration

131
Q

stroke volume variation on inspiration of hypovolemic, cardiac tamponade, or pneumothorax patients during spontaneous ventilation

A

Systolic blood pressure and pulse pressure decrease >10mmHg during inspiration

132
Q

stroke volume variation on inspiration of healthy patients during mechanical ventilation

A

Systolic blood pressure and pulse pressure increase 5-10% during inspiration

133
Q

stroke volume variation on inspiration of hypovolemic patients during mechanical ventilation

A

Systolic blood pressure and pulse pressure increase >10-15% during inspiration

134
Q

the monitor used to tell us the stroke volume variation and whether or not stroke volume variation is normal or exaggerated

A

Flo Trac sensor

135
Q

2 advantages of the Flo Trac sensor

A
  1. noninvasive monitor

2. gives a real time blood pressure without having to cannulate the artery

136
Q

2 disadvantages of the Flo Trac sensor compared to arterial lines

A
  1. arterial lines give access to drawing blood from labs

2. the blood pressure readings aren’t as accurate as A-lines

137
Q

4 things the Flo Trac sensor can tell us noninvasively

A
  1. stroke volume variation
  2. stroke volume and stroke volume index (calculated cardiac output)
  3. SVR (from waveform downstroke)
  4. cardiac output/index (by using SVR equation)
138
Q

how does the Flo Trac sensor measure cardiac index

A

Uses the cardiac output equation

  • knows the MAP from the blood pressure waveform
  • knows the SVR from the waveform downstroke
  • does not know CVP, so inserts a normal value of 7 mmHg
  • —CVP has minimal effect on cardiac output equation
139
Q

the 3 most common methods to assess volume status

A
  1. monitoring urine output
  2. look for hypotension and tachycardia
  3. monitor CVP (requires a central line)
140
Q

2 ways anesthetists decide how much fluid to give

A
  1. calculating “guessing” fluid replacement

2. monitoring BP, HR, urine output, CVP

141
Q

monitoring stoke volume variation on the Flo Trac sensor helps the anesthetist with _____ _____

A

fluid management

142
Q

what is suspected If the stroke volume increases more than expected (>10-15%) during mechanical inspiration

A

hypovolemia

-the anesthetist should give fluids until the stroke volume variation gets down toward 10%

143
Q

5 limitations of monitoring stroke volume variation using Flo Trac sensor

A
  1. the patient must be 100% mechanically ventilated
    - stroke volume variation monitoring is not as accurate on spontaneous ventilating patients
  2. RR needs to be fixed
  3. tidal volume needs to be greater than 8 mL/ kg
  4. the patients HR must be regular
  5. PEEP and vasodilators may alter SVV

Patient Monitoring/ Instrumentation Kristi (4 decks)

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