Advanced Hemodynamic Monitoring Flashcards

1
Q

Cardiac Index Normal Value

A

2.2-4.2 L/min/m^2

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2
Q

Central venous pressure CVP normal value

A

5-12 mmHg

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3
Q

when is CVP most accurately measured?

A

end of expiration

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4
Q

in what patient position is CVP considered NOT accurate?

A

if a patient is sitting

should be backrest from 0-60 degrees

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5
Q

coronary perfusion pressure normal value

A

50-120 mmHg

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6
Q

mixed venous oxygen saturation (mvO2) normal value

A

60-80% in awake pt

roughly equal to central venous oxygen saturation (ScvO2)

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7
Q

pulmonary artery pressure (PAP) normal value

A

15-30/10 mmHg

not as accurate when sitting

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8
Q

mild pulmonary Htn value of PAP systolic

A

36-49 mmHg systolic

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9
Q

moderate pulmonary Htn value of PAP systolic

A

50-59 mmHg systolic

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10
Q

severe pulmonary Htn value of PAP systolic

A

> 60 mmHg systolic

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11
Q

pulmonary capillary wedge pressure (PCWP) normal value

A

less than 12mmHg

not considered accurate if sitting

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12
Q

PCWP is _____ mmHg less than pulmonary artery diastolic pressure

A

1-4mmHg

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13
Q

pulmonary vascular resistance (PVR) normal value

A

100-300 dynesseccm-5

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14
Q

stroke volume normal value

A

60-90mL/beat

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15
Q

stroke volume index normal value

A

20-65mL/beat/m^2

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16
Q

systemic vascular resistance (SVR) normal value

A

700-1200 dynesseccm-5

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17
Q

central venous O2 saturation (ScvO2)

A

25-30% below patients SaO2

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18
Q

what do the bainbridge and baroreceptor reflex have in common?

A

both control the heart rate

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19
Q

baroreceptor reflex definition

A

responds to changes in blood pressure inside the carotid sinus and aortic arch

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20
Q

bainbridge reflex definition

A

responds to changes in blood volume inside the heart

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21
Q

what are the two things the bainbridge reflex causes if the right atrial pressure increases?

A

increased heart rate

vasodilation (decreasing venous return)

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22
Q

what happens to the heart with a low CVP baroreceptor reflex and high CVP bainbridge reflex?

A

increase in HR for both

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23
Q

What does the normal cardiac output values depend on?

A

the size of the patient

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24
Q

cardiac index definition

A

allows more accurate interpretation of cardiac output b/c number is not skewed by weight

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25
Q

cardiac index equation

A

cardiac output/body surface area

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26
Q

assuming two patients are healthy which would differ and which would be the same?
cardiac output
cardiac index

A

cardiac output would differ

cardiac index would be the same

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27
Q

Stroke volume index equation

A

=stroke volume/body surface area

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28
Q

stroke volume index definition

A

allows more accurate interpretation of stroke volume because the number is not skewed by weight

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29
Q

coronary perfusion pressure (CPP) equation 1

A

CPP= DBP-LVEDP

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30
Q

how can we estimate LVEDP?

A

because it is roughly equal to systolic pressure in the left atrium (left atrial pressure) which is roughly equal to PCWP

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31
Q

coronary perfusion pressure (CPP) equation 2

A

CPP= DBP - CVP

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32
Q

what are the 3 estimations for LVEDP

A

~ left atrial pressure (LAP)
~left atrial pressure (LAP) ~ PCWP
~PCWP ~ PA diastolic pressure

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33
Q

what are the 3 equations CPP can be estimated by?

A
CPP= DBP-CVP
CPP= DBP- PCWP
CPP= DBP- PA diastolic pressure
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34
Q

what are the four parts to thermodilution technique

A

10mL saline injected into RA (<4sec)
cold fluid travels to thermistor
cold fluid is warmed to a degree
monitor produces waveform based on coldness of fluid

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35
Q

high cardiac output thermistor chart

A

get cold fast but warm up quickly

area under curve is lower than normal

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36
Q

low cardiac output thermistor chart

A

will stay cold for longer period of time

area under curve is higher than normal

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37
Q

a factor that decreases the area under the thermodilution curve will over or underestimate CO?

A

overestimate CO

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38
Q

a factor that increases the area under the curve will over or underestimate CO?

A

underestimate CO

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39
Q

how is cardiac output related to the area under the thermodilution curve?

A

inversely

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40
Q

what would happen if you prolonged the injection time?

A

the curve would be larger than normal which means the cardiac output reading would be underestimated

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41
Q

what are the two things that have replaced thermodilution?

A

continuous cardiac output (CCO) pulmonary artery catheters

transesophageal echocardiography TEE

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42
Q

central venous O2 saturation where is the blood draw from and with what?

A

oxygen saturation of blood from superior vena cava drawn from the central venous line port

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43
Q

which will be lower mvO2 or ScvO2? why?

A

mvO2

because coronary sinus blood is more deoxygenated than other blood

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44
Q

what are the three things that make up mvO2?

A

superior vena cava
inferior vena cava
coronary sinus

45
Q

how does mvO2 and ScvO2 relate to low cardiac output?

A

lower mvO2 and ScvO2 bc the blood has more time to become deoxygenated

46
Q

how does mvO2 and ScvO2 relate to high cardiac output?

A

higher mvO2 and ScvO2 bc the blood has less time to become deoxygenated

47
Q

what are the two reasons that ScvO2 and mvO2 are rarely used anymore?

A

requires drawing blood from central line or swan

CO can be estimated by other effective methods

48
Q

Ohms law

A

V= IR

49
Q

what does ohms law describe

A

the factors that affect flow through an electrical circuit

50
Q

V=

A

voltage

MAP - CVP

51
Q

I=

A

current

analogous to cardiac output

52
Q

R=

A

resistance
systemic vascular resistance or
pulmonary vascular resistance

53
Q

applying ohms law to cardiac output 2 equations

A
CO= (MAP-CVP/SVR) (80)
CO= (PAP-PCWP/PVR) (80)
54
Q

What are the three factors that affect pulse pressure?

A

stroke volume
systemic vascular resistance
aortic compliance

55
Q

Does stroke volume primarily effect systolic or diastolic blood pressure?

A

systolic pressure

56
Q

increased stroke volume does what to systolic pressure?

A

increase

57
Q

does systemic vascular resistance primarily effect systolic or diastolic pressure?

A

diastolic pressure

58
Q

increased SVR does what to diastolic pressure?

A

increased

59
Q

out of the three factors that effect pulse pressure which one of them is inversely related to pulse pressure?

A

aortic compliance

60
Q

if aortic compliance is high then what does that do to systolic pressure?

A

decrease systolic pressure

61
Q

a pt is hypovolemic.

wide or narrow PP?

A

narrow

low SV and vasoconstriction

62
Q

a pt has CHF.

wide or narrow PP?

A

narrow

low SV and vasoconstriction

63
Q

pt ran 3 miles

wide or narrow PP?

A

wide

high SV and vasodilation

64
Q

pt has cardiac tamponade.

wide or narrow PP?

A

narrow

low SV and vasoconstriction

65
Q

pt has aortic stenosis

wide or narrow PP?

A

narrow

low SV and vasoconstriction

66
Q

pt is on milrinone drip (causes increase contractility and decrease SVR)
wide or narrow PP?

A

wide

high SV and vasodilation

67
Q

pt has aortic regurg.

wide or narrow PP?

A

wide

diastolic BP will be lower

68
Q

What are the 5 causes of high CVP?

A
fluid overload
HF
Pulm HTN
trendelenburg
high intrathoracic pressure (tension pneumo)
69
Q

what are the 2 causes of low CVP?

A

hypovolemia

sitting position

70
Q

what is the cause of low SVR?

A

vasodilation

71
Q

what are the 5 potential causes of low cardiac index?

A
decreased contractility
bradycardia
hypovolemia
hypervolemia (CHF)
increased afterload (aortic stenosis/high SVR)
72
Q

cause of high SVR?

A

vasoconstriction

73
Q

3 causes of high cardiac index

A

increased contractility/SV
tachycardia
vasodilation (decreased afterload)

74
Q

hypovolemia treatment

A

treat with fluids and/or blood products

75
Q

vasodilation treatments 2

A

vasopressors

reversing the cause of the vasodilation (turn does anesthetic)

76
Q

HF (decreased contractility) treatment

A

inotropes

diuretics (due to fluid overload)

77
Q

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

A
Cardiac index?
Decreased
CVP?
Decreased
SVR?
Increased
78
Q

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

A

Cardiac index?
Increased
SVR?
Decreased

79
Q

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

A
Cardiac index?
Decreased
CVP?
Increased
SVR?
Increased
80
Q

SEE PRACTICE QUESTIONS ON SLIDES 73-76

A

ANSWER ON SLIDES

81
Q

Stroke volume variation (SVV) definition

A

stroke volume and systolic blood pressure fluctuating during inspiration and expiration

82
Q

another name for stroke volume variation

A

pulse pressure variation

83
Q

in a healthy spontaneously ventilation pt does the systolic BP normally increase or decrease and by how many mmHg?

A

decrease

5-10 mmHg

84
Q

what causes spon vent pts systolic BP to decrease during inspiration? (4 things)

A

pulmonary vessels vasodilate during inspiration
vasodilation causes blood to pool in lung
less blood then available to pump
leads to slight drop in BP

85
Q

in healthy mechanically ventilating pt does the systolic BP normally increase or decrease and by how many mmHg?

A

increase 5-10%

86
Q

what causes mech vent pts systolic BP to increase during inspiration? (2)

A

lung inflation displaces LV wall during systole assisting in contraction
squeezes blood out of pulm capillaries and into LA increasing volume and SV

87
Q

pulsus paradoxus definition

A

SV/systolic BP has wider than expected fluctuations during inspiration and expiration

88
Q

if the systolic BP decreases more than 10mmHg during spon breathing then the patient has what?

A

pulsus paradoxus

89
Q

if the systolic BP increases more than 10-15% during mechanical breathing the patient has what?

A

pulsus paradoxus

90
Q

where can pulsus paradoxus be detected on our monitors? 2

A

SpO2 waveform

arterial line waveform

91
Q

what is the most common cause of pulsus paradoxus?

A

hypovolemia

92
Q

what are the two causes of pulsus paradoxus (other than hypovolemia)?

A

cardiac tamponade

tension pneumothorax

93
Q

what are the 4 LEAST common causes of pulsus paradoxus

A

vasodilation
CHF
hypervolemia
PEEP

94
Q

cardiac tamponade mechanism for pulsus paradoxus

A

1 during inspiration blood in RV increases
2 right ventricular wall cannot expand
3 force the interventricular septum to bulge over to left
4 decrease SV and greater decrease in BP during inspiration

95
Q

what does the heart normally do to compensate for the increased blood in the RV during inspiration?

A

the RV wall would expand and absorb the increased pressure

96
Q

tension pneumothorax mechanism for pulsus paradoxus

A

same mechanism as cardiac tamponade

but the RV cant expand due to external compression on the heart from the increased intrathoracic pressure

97
Q

what is a FloTrac Sensor (EV1000)

A

like an arterial line in the sense that it produces a blood pressure waveform

98
Q

what are the 4 things that a EV1000 can tell us?

A

stroke volume and stroke volume index (from waveform upstroke)
SVR (waveform downstroke)
stroke volume variation
MAP (area under wave)

99
Q

what is the noninvasive A-line?

A

flotrac sensor EV1000

100
Q

Can the EV1000 calculate CO and CI?

A

yes because it just plugs in 7mmHg for CVP and calculates that way
will be fairly accurate bc CVP has minimal effect on CO

101
Q

most common methods to assess volume status 3

A

monitor urine
look for hypotension/tachycardia
monitor CVP

102
Q

anesthetists usually decide how much fluid to give by

A

calculating fluid replacement

monitoring BP, HR, urine, CVP

103
Q

With the Flotrac sensor how would we monitor fluids?

A

titrate fluids until the SVV gets into a normal range

104
Q

what is the implication of the EV1000?

A

invasive central line and swans are no longer needed to assess volume or CO

105
Q

3 limitations of the EV1000?

A

patient must be 100% mechanically ventilation
heart rhythm must be regular (not accurate in afib)
PEEP and vasodilator may alter the SVV

106
Q

what must the tidal volume be for patients on the EV1000?

A

> 8mL/kg

107
Q

SVV> 13%, SVI is 40-50 and is not responsive to fluid bolus, next step?

A

suggests contractility is normal so probably dilated

pressor

108
Q

SVV> 13%, SVI is <20 and is not responsive to fluid bolus, next step?

A

suggests low cardiac contractility

inotrope

109
Q

SVV>13%, SVI is >50 and is not responsive to fluid bolus, next step?

A

suggests that the pt is in fluid overload

diuretic