12. Arterial Lines Flashcards
1
Q
what can happen if the art line tubing becomes disconnected?
A
the pt could rapidly bleed to death
2
Q
2 purposes for arterial lines
A
- real time blood pressure
- blood samples
3
Q
how often does an art line provide blood pressure
A
every time the heart beats
4
Q
why cant you draw blood out of an IV?
A
pressure in veins is too low (7mmHg)
vein would flatten
5
Q
adult art line sizing
A
20ga
18ga
6
Q
radial/brachial catheter size
A
20ga
7
Q
femoral catheter size
A
18ga
8
Q
peds art line sizing
A
20-22ga
9
Q
neonates art line sizing
A
22-24ga
10
Q
NIBP reading vs art line
A
NIBP under-reads systolic
NIBP over-reads diastolic
11
Q
Art line vs NIBP
A
Art systolic is higher than NIBP
Art diastolic is lower than NIBP
12
Q
gold std for BP monitoring
A
arterial lines
13
Q
pressure transducer
A
senses BP inside artery
14
Q
why do some providers use heparinized saline?
A
less chance of art line system clotting
15
Q
why do some providers not use heparinized saline?
A
eliminates possiblity of HIT
16
Q
2 purposes of pressure bag
A
prevents blood from backing into tubing
allows fluid flush of artery
17
Q
when the 500mL bag of N/S is pressurized, it allows
A
the pressure in the tubing to be higher than the pressure in the blood
18
Q
when do you fluid flush an art line into the pt
A
after labs are drawn to flush the blood back into the pt
19
Q
can you give drugs through an arterial line
A
no
20
Q
why should you not give drugs via art line
A
cause vasoconstriction and ischemia
21
Q
what should never be flushed into artery
A
air bubbles
22
Q
which direction should the stopcock be turned in order to flush?
A
off to air
23
Q
4 reasons an art line wont flush
A
- stopcock turned off to the line
- closed roller clamp
- “under pressurized” pressure bag
- clotted off catheter
24
Q
how to fix a clotted off art line?
A
try to aspirate clot w/syringe
flush line
25
materials required to insert art line
chloraprep
guaze
tegadern
tape
lidocaine
arrow/angiocath
wrist support/roll
26
2 catheter types for art lines
20ga arrow catheter
regular 20ga catheter
27
what pressure do you inflate the N/S bag to?
250-300mmHg
28
what rate will the fluid drip into the artery with a correctly pressurized bag?
3-6mL per hour
29
when can the transducer be exposed to the atmosphere?
1. if the stopcock if off to the pt, the stopcock will be open to air
2. before the link is hooked up to the catheter in the artery
30
how do you zero the art line?
open the system to the atmosphere
press "zero"
31
steps to zeroing transducer
1. change monitor to 8 wave
2. turn stopcock OFF to pt (OPEN to air) and remove cap
3. push zero
4. turn stopcock OFF to atmosphere
5. replace cap
32
what direction is the stopcock off to pt
away from transducer
towards noncompliant tubing
33
MAP
area under the curve
34
upstroke
systole
cardiac contractilioty
35
sharp vertical upstroke
good contractility
36
sloped sluggish upstroke
poorer contractility
37
downstroke
diastole
SVR
38
slow fall downstroke
vasoconstriction
high SVR
39
shar fall downstroke
vasodilation
low SVR
40
dicrotic notch
diastolic blood hits the aortic valve
41
overdamped waveform
smoother/lower amplitude
underestimates systolic
overestimates diastolic
no change to MAP
42
are overdamped waveforms accurate?
overdamped waveforms are inaccurate
43
causes of damping in waveform
1. partially clotted catheter
2. kinked catheter from wrist flexion
3. compliance in tubing
4. low pressure in system
5. air bubbles
44
why is art line tubing non-compliant?
to reduce dampning
increase pressure accuracy
45
how to fix dampened wave form?
1. aspirate blood/flush tubing
2. extend wrist
3. ensure adequate pressure (250-300 mmHg)
4. aspirate air bubbles
46
underdamped waveform AKA
hyperresonant waveform
waveform w/overshoot
47
underdamped waveform BP effects
overestimated systolic
underestimated diastolic
MAP unchanged
48
underdamped waveform characteristics
too much detail
49
causes of underdamped waveform
1. defective transducer
2. tachycardia
50
most likely cause of underdamped waveform
defective transducer
just replace it
51
square wave high pressure test
flush of system and evaluate waveform
52
optimally damped
flush system
wave returns to baseline after 1 oscillation
53
underdamped
flush system
wave oscillates multiple times before returning to baseline
54
overdamped
flush system
wave does not oscillate
wave returns to baseline immediately
55
constructive interference of waves
waves of similar frequencies are additive
combine to form higher peak amplitude
56
natural (resonant) frequency of art line
20Hz
57
fundamental frequency of art line
1-2 Hz
58
what is the fundamental frequency derived from
pulse rate
59
fundamental frequency of 60bpm HR
1 Hz
60
fundamental frequency of 120bpm HR
2 Hz
61
at what frequency ratio can the wave from become distorted/inaccurate?
if natural freq < 10x fundamental freq
62
what is the most common cause of constructive interference?
tachycardia
63
what can tachycardia cause in a art line
resonance
underdamping
-- artificially high systolic
64
resonance occurs when
a wave gets bigger because external force w/similar frequency was applied to it
65
what can counteract resonance
damping
66
an optimally damped system has a damping coefficient of
0.6-0.7
67
high damping coefficient
ovedamped waveform
68
low damping coefficient
underdamped waveform
69
most common arterial line insertion sites
radial
70
the radial is commonly used because
superficial location
low complication rates
71
radial artery controls blood supply to
digits
72
ulnar arterial line
more difficult
deeper
increased chance of nerve damage
73
when do you avoid ulnar placement
if ipsilateral radial attempt has failed
you could lose all blood supply to hand
74
brachial arterial line
only used if other sites are not available
limited collateral circulation
hemorrhage risk
75
axillary arterial line
high risk of nerve damage to brachial plexus
highest risk of cerebral emboli
76
why is the axillary artery the highest risk of cerebral emboli
most proximal to the brain
left is slightly safer than right axillary
77
where is the highest risk of cerebral emboli
right side axillary artery
78
what is the largest arterial line site
femoral artery
79
where do you palpate for femoral pulse
inner thigh
mid-inguinal point
80
when do you place a femoral line
emergency only
81
when are femoral lines contraindicated
if pt has a femoral central line on same side
(leads to arteriovenous malformation)
82
femoral art line complications
1. hole in femoral artery
2. possible femoral nerve damage
3. higher infection rates
83
NAVEL
Nerve
Artery
Vein
Empty
Lymphatics
femoral line placement
84
most distal art line sites
dorsalis pedis
posterior tibial
85
art line waveforms at distal sites
1. waveform becomes more dampened (loses detail)
2. higher systolic
3. lower diastolic
4, unchanged/slight lower MAP
86
why is the waveform more dampened at distal sites
proximal arteries absorb pressure
more compliance loss by the time the blood reaches distal site
87
Arteries: Proximal to Distal
aortic root
subclavian
axiallary
brachial
radial
femoral
dorsalis pedis
88
BP reading in distal arteries
higher resonance = higher BP
89
allen's test
1. exsanguinate hand (make fist)
2. occlude radial/ulnar
3. relax hand
4. release ulnar pressure
90
positive allen test
adequate collateral circulation
<7 seconds
91
uncertain allen test
8-15 seconds
92
negative allen test
inadequate collateral circulation
>15 seconds
93
allen's test indicates what
whether or not ulnar collateral circulation to hand is adequate
94
do we use allens test
not really
its nonspecific
95
what is a replacement for allens test
monitor pulse ox during occlusion of radial artery
96
art line complications
1. limb ischemia
2. neurologic injury
3. infection
4. hemorrhage
5. data misinterpretation
97
causes of limb ischemia
thrombosis
too small of vessel for catheter
medication injection into artery
vasospasm
98
causes of neurologic injury
needle injury
hematoma adjacent to nerve
prolonged wrist extension
stroke
99
why do you not perform continuous flush of art line
risk of thrombus or air emboli
100
which has a higher infection rate, arterial line or central line?
central lines are more likely to be infected
101
arterial line transducer should be leveled to...
the phlebostatic axis
102
for every ____ the transducer is below the catheter, the fluid pressure increases by ______
for every 1 inch the transducer is below the catheter, the fluid pressure increases by 1.87 mmHg
103
transducer below level of heart
overestimates BP
104
transducer above level of heart
underestimates BP
105
transducers in sitting pts should be leveled
transducers should be leveled to the external auditory meatus in sitting pts to know the BP at the brain
106
in sitting pts, transducers at the level of the heart will _______ BP at the level of the head
overestimate BP
actual BP will be lower than reading
107
in sitting pt, if you level the transducer at the external auditory meatus, you will ________ pressures.
understimate CVP
underestimate PAP
108
will art line BP change if pt moves their arm with the cather inserted?
no
the pressure reading is based off of transducer location, not cather location.
109
pulsus bisferians
2 dicrotic notches
110
causes of pulsus bisferians
1. hypertropic cardiomyopathy
2. severe aortic regurgiation
111
hypertrophic cardiomyopathy
enlarged interventricular septum
narrows left ventricular outflow tract
112
severe aortic regurge
blood reenters LV during diastole
temporaroly decreases blood flow during mid-systole
113
