17. Adv Hemodynamic Monitoring Flashcards
1
Q
cardiac index normal range
A
2.2-2.4 L/min/m2
2
Q
CVP normal range
A
5-12 mmHg
3
Q
when is CVP most accurately measured
A
end of expiration
4
Q
when is CVP not considered accurate
A
pt is “sitting”
5
Q
what degree must the pt head be resting at to be considered accurate
A
between 0-60 degrees
6
Q
coronary perfusion pressure normal
A
50-120mmHg
7
Q
mixed venous oxygen saturation (mvO2)
A
60-80% in awake pt
8
Q
mvO2 is approximately the same as
A
ScvO2
(central venous oxygen saturation)
9
Q
pulmonary artery pressure (PAP)
A
15-30/10 mmHg
10
Q
when is PAP not considered accurate
A
if pt is sitting
11
Q
pulmonary hypertension: mild
A
36-49 mmHg (systolic)
12
Q
pulmonary hypertension: mod
A
50-59 mmHg (systolic)
13
Q
pulmonary hypertension: severe
A
> 60 mmHg (systolic)
14
Q
pulmonary capillary wedge pressure (PCWP)
A
<12mmHg (mean pressure)
15
Q
PCWP should be _______ less than pulmonary artery ______ pressure
A
1-4mmHg less than pulmonary artery diastolic pressure
16
Q
when is PCWP not considered accurate
A
if pt is sitting
17
Q
pulmonary vascular resistance (PVR)
A
100-300 dynes sec cm-5
18
Q
stroke volume (adult)
A
60-90 mL/beat
19
Q
stroke volume index
A
33-47 mL/m2/beat
20
Q
systemic vascular resistance (SVR)
A
700-1200 dynes sec cm-5
21
Q
ScvO2 (central venous O2 saturation)
A
25-30% below pt SaO2
OR
70-75% if the SaO2 is normal
22
Q
what reflex control heart rate
A
bainbridge
baroreceptor
23
Q
baroreceptor reflex
A
responds to changes in BP
low BP = incr HR
high BP = decr HR
24
Q
bainbridge reflex
A
responds to change in blood volume
25
2 bainbridge reflexes
incr BV in RA
1. incr HR (pump extra blood out)
2. vasodilation (decr venous return)
26
what causes incr in HR
low CVP (baro)
high CVP (bain)
27
what does cardiac output vary based on
the pt weight
28
normal CO for 70kg pt
5L/min
29
200kg pt CO
higher than 5L/min
30
cardiac index equation
CI = CO/body SA
31
the cardiac index is independent of_____
weight
32
normal range of cardiac index is
same for all pts, regardless of size
33
stroke volume varies with
weight
34
stroke volume index equation
SVI = SV/body SA
35
Coronary perfusion pressure equations
CPP = DBP - LVEDP
OR
CPP = DBP - CVP
36
LVEDP
BP in LV at end of diastole
37
what is a good estimate of LVEDP
LVEDP~LAP~PCWP~PA diastolic P
38
CPP equations
CPP = DBP - PCWP
CPP = DBP - PA diastolic Pressure
CPP = DBP - CVP
39
what is required for adequate coronary perfusion pressure
adequate diastolic filling time
adequate blood pressure
40
thermodilution steps
1. 10mL cold saline into RA (fast <4s)
2. thermistor located in pulmonary artery
3. thermistor monitors fluid temp
41
thermodilution curve: high CO
low Area Under Curve
small wave
- cold fluid passes thermistor quickly
42
thermodilution curve: low CO
higher Area Under Curve
large wave
- thermistor will stay colder longer
43
CO relationship with thermodilution curve
CO is inversely proportional to area under thermodilution curve
44
what has replaced thermodilution
Continuous cardiac output PACs
TEE
45
what can cause false readings in thermodilution
prolonged injection time
>4s
46
a prolonged injection time would cause
CO reading to be underestimated
47
R-L shunt: thermodilution curve
fluid less cold (losing 1/2 cold)
AUC smaller
overestimation of CO
48
L-R shunt: thermodilution
fluid less cold (diluted)
AUC smaller
overestimation of CO
49
triscuspid regurge: thermodilution
fluid colder longer
AUC larger
underestimation of CO
50
ScvO2
O2 saturation of blood taken from SVC
drawn from central line port
51
mvO2
drawn from PA
- mixed sample of SVC, IVC, and coronary sinus blood
52
which blood sample contains venous blood from the heart?
mvO2
53
which blood sample will be more deoxygenated?
mvO2
(coronary sinus blood is more deoxy because the heart burns more O2 than other organs)
54
which is lower: mvO2 or scvO2
mvO2 < scvO2
55
low CO: mvO2 and scvO2
low CO = lower mvO2/ScvO2
(blood is more deoxygenated)
56
high CO: mvO2 and scvO2
high CO = higher mvO2/ScvO2
(blood is less deoxygenated)
57
mvO2 and CO correlation
directly proportional
58
causes of Low ScvO2/mvO2
hypoxia
hypoventilation
incr metabolic rate (incr O2 demand)
low CO
59
causes of High ScvO2/mvO2
decr metabolic rate (decr O2 demand)
mitochondrial dysfunction
60
intubating the esophagus causes
decr SpO2
decr ScvO2
decr mvO2
61
when can mitochondrial dysfunction occur
in sepsis
62
how does mitochondrial dysfunction cause high ScvO2/mvO2
mitochondria unable to uptake O2 well
higher [O2] in blood
63
Ohm's law
V=IR
voltage = current x resistance
64
resistance (R)
SVR
or PVR
65
current (I)
CO
66
voltage definition
difference in energy between two ends of a circuit
67
voltage (V)
MAP - CVP
difference in BP at arterial end and the venous end
OR
PAP-PCWP
difference in BP at the pulmonary arterial end and pulmonary venous end
68
Ohm's law for CO
(MAP - CVP) = CO x SVR
69
CO equation
CO = [(MAP-CVP)/SVR]x80
OR
CO = [(PAP-PCWP)/PVR]x80
70
SVR equation
SVR = [(MAP-CVP)/CO]x80
71
SVR units
dynes/sec/cm-5
72
CO units
L/min
73
PVR equation
PVR = [(PAP-PCWP)/CO]x80
74
PVR units
dynes/sec/cm-5
75
narrow pulse pressure
<25% of systolic pressure
76
wide pulse pressure
>50% of systolic pressure
77
does stroke volume have a great effect on systolic or diastolic?
systolic
78
increase SV = ______ pulse pressure
incr SV = incr PP
79
does SVR have a greater effect on systolic or diastolic?
diastolic
80
increase SVR = _______ pulse pressure
incr SVR = decr PP
81
pulse pressure is ________ proportional to aortic compliance
inversely proportional
82
aorta w/good compliance (young healthy pt)
systolic pressure is lower in systole
PP is lower
83
aorta less compliant (older pt)
systolic pressure is higher in systole
PP is higher
84
pulse pressure: hypovolemic pt
Narrow PP
decr SV = decr systolic
vasoconstriction = incr diastolic
85
pulse pressure: congestive heart failure
Narrow PP
decr SV = decr systolic
vasoconstric = incr diastolic
86
pulse pressure: post-workout
Wide PP
incr SV = incr systolic
vasodilate = decr systolic
87
pulse pressure: cardiac tamponade
Narrow PP
decr SV = decr systolic
vasoconstrict = incr diastolic
88
pulse pressure: aortic stenosis
Narrow PP
decr SV = decr systolic
vasoconstrict = incr diastolic
89
pulse pressure: milrinone
Wide PP
incr contractility = incr SV = incr systolic
decr SVR = decr diastolic
90
pulse pressure: aortic regurge
Wide PP
incr SV
vasodilation
91
intraoperative causes of high CVP
fluid overload
HF
pulm HTN
Tburg
high intrathoracic pressure
92
treatment: high CVP - fluid overload
diuretics
fluid restriction
93
treatment: high CVP - HF
inotropes
94
treatment: high CVP - pulm HTN
hyperventilation
higher FiO2
pulm vasodilators
95
treatment: high CVP - high intrathoracic P
needle decompression
chest tube
96
intraoperative causes of low CVP
hypovolemia
reverse Tburg
sitting
97
treatment: low CVP - hypovolemia
fluid resuscitation
98
causes of low SVR
vasodilation
99
treatment: low SVR - vasodilation
lighten anesthetic
give vasopressors
100
causes of high SVR
vasoconstriction
101
treatment: high SVR - vasoconstriction
vasodilator
102
causes of low cardiac index
decr contractility
bradycardia
hypovolemia
hypervolemia (CHF)
incr afterload
- aortic stenosis
- high SVR
103
causes of high cardiac index
incr contractility
incr SV
tachycardia
vasodilation
(decr afterload = incr SV)
104
symptoms of HF
low cardiac index
hypotension
incr SVR
pulm HTN (pulm edema)
high CVP
105
what does the body do when CO is low
vasoconstricts to prevent BP from getting too low
106
treatments for HF
inotropes
diuretics
107
hypotension due to hypovolemia
CI: low
CVP: low
SVR: high
108
hypotension due to vasodilation
CI: high
SVR: low
109
hypotension due to decreased contractility
CI: low
CVP: high
SVR: high
PAP: high
110
stroke volume variation
SV fluctuation between inspiration and expiration
(AKA PPV)
111
in spontaneously ventilating pts, SBP __________ during inspiration
in spontaneously ventilating pts, SBP decreases 5-10mmHg during inspiration
112
why does SBP decrease during inspiration for SV?
Pulm vessels vasodilate
blood pools in legs
decr preload
decr BP
113
in mechanically ventilated pts, SBP _________ during inspiration
in mechanically ventilated pts, SBP increases 5-10% during inspiration
114
why does SBP increase during inspiration for mechanical ventilation?
lungs inflate
pushes LV wall inward during systole
incr EF
incr blood volume/SV
115
SV/SBP has wider fluctuations during insp/expir
pulsus paradoxus
116
pulsus paradoxus SBP
SBP decr >10mmHg for spontaneous inspiration
SBP incr >10-15% for mechanical inspiration
117
causes of pulsus paradoxus
hypovolemia
cardiac tamponade
pneumothorax
118
how does cardiac tamponade/tension pneumo cause pulsus paradoxus?
inspiration
incr BV in RV
RV cannot expand
interventricular septum pushes into LV
decr volume of LV
decr SV
decr BP
119
EV1000/Flo Trac monitors
beat to beat BP
SVR
CO
SV/SVI
SVV
120
EV1000/Flo Trac uses ______ for CVP
7mmHg
121
monitor volume status
urine output
hypotension/tachycardia
CVP
122
what is the FloTrac good for
fluid management
High SVV ~ hypovolemia
123
Flo Trac limitaitons
requires mech venitloation
fixed RR
TV > 8ml/kg
regular heart rhythm
SVV altered by PEEP/vasodilators
124
pulsus alternans
variation in BP every other beat
125
causes of pulsus alternans
severe ventricular dysfunction
126
electrical alternans
alternation of QRS between beats
127
causes of electrical alternans
cardiac tamponade
myocardial infarction
