Apex- Monitors and Equiptment > Hemodynamics Flashcards
A blood pressure cuff that is too large:
A- falsely increases BP measurement
B- requires less pressure to occlude the artery
C- increases risk of radial neuropathy
D- has a bladder width of less than 40% of the circumference of the extremitiy
B. requires less pressure to occlude the artery
The ideal bladder length and width of a BP cuff should be what % of the extremity circumference
80% length
40% width
Where is SBP/DBP the lowest vs highest
& Where is the PP most narrow vs widest
At the aortic root → SBP lowest, DBP highest, PP narrowest
At the dorsalis pedis artery → SBP is highest, DBP is lowest, and PP is the widest
Arm positioning:
For every 10cm change, the BP changes by ________ mmHg.
For every 1” change, the BP changes by ________ mmHg
10cm = 7.4mmHg change
1” = 2mmHg change
If the BP cuff location is above the heart, the BP reading wil lbe falsey (increased/decreased) - why
what if it’s below the heart?
above the heart- falsely decreased → less hydrostatic pressure
below the heart - falsey increased → more hydrostatic pressure
If the BP cuff is 10” below the level of the heart. What is the true BP at the level of the heart?
10” x 2mmHg = 20mmHg
20mmHg less than what’s displayed on the monitor
Why should BP cuff measurement probably be avoided in someone with a previous axillary lymph node dissection?
It is thought it could impair lymphatic drainage and cause limb edema but is controversial
3 most common causes of an over-dampened arterial-line waveform:
2 other things to check for
- air bubbles in the tubing
- clot at the catheter tip
- low flush bag pressure
kinks or a loose connection
Arterial line associations:
Initial upstroke →
Peak of the waveform →
Dicrotic notch →
Trough of the waveform →
Area under the curve →
Peak minus trough value →
Initial upstroke → contractility
Peak of the waveform → systolic BP
Dicrotic notch → Aortic valve closure
Trough of the waveform → Diastolic BP
Area under the curve → Stroke volume
Peak minus trough value → Dicrotic notch
Where should your a-line transducer be leveled at?
What if your concernred about cerebral perfusion?
Right atrium
External auditory meatus (corresponds with the circle of Willis)
Characteristics of your BP components with an underdampened a-line system
2 things that could cause it
2 signs in your waveform that may indicate it’s underdampened
SBP will be overestimated
DBP will be underestimated
MAP = accurate
stiff/noncompliant tubing & catheter whip (artifact)
multiple artifacts present in the waveform + after flushing the system, theres severeal oscillations that occur prior to re-establishing baseline
Why should you probably always be looking at MAP when evaluating arterial lines
bc if your system is overdampened or underdampned, your MAP will always be accurate
What are the specific BP characterstics of an over-dampened arterial line system?
2 things you’ll notice in your waveform
5 things that can cause it
SBP is underestimated
DBP is overestimated
MAP is accurate
loss of dicrotic notch & no oscillations following a flush
air bubble in tubing, clot in catheter, low flush bag pressure, kinked tubing, loose connection
Where should the tip of the CVP catheter rest?
just above the junction of the vena cava and the right atrium (not inside the right atrium)
When inserting a central line in the right IJ, how far should the catheter be advanced to achieve the correct placement?
15cm
Where should the tip of the PA catheter reside?
how far from the VC junction?
in the pulmonary artery, distal to the pulmonic valve
25-35cm from the VC junction (so ~45cm from skin)
While floating a swan, what is the classic presentation of a pulmonary artery rupture?
hemoptysis
Other than close proximity, why do we access the right IJ over the left IJ?
Left IJ carriers the highest risk of injuring the thoracic duct (risk of chylothorax)
What is the most common complication while obtaining central access?
dysrhythmias
The incidence of catheter- related infection increases after how many days?
3 days
Why don’t we place the CVP tip in the right atrium?
can cause dysthryhmias, thrombus formation, and cardiac perforation
fill out chart
label distances
If you advance a PA catheter 10cm beyond the calculated distance and still dont see the expected waveform, what should you assume and do?
assume the catheter coiled
→ deflate the balloon, withdraw the catheter to the junction of the VC and RA and try again.
if you encounter resistance while pulling back, the catheter is possibly knotted or entangled with the chordae tendineae → get CXR to rule out
What kind of complications can occur while obtaining central venous access (5)
Arterial puncture
PTX
Air embolism
Neuropathy
Catheter knot
What kind of complications can occur while floating a PA catheter? (4)
- PA rupture (hemoptysis)
- RBBB
- CHB if pre-existing LBBB
- Dysrhythmias
A- Wave
atrial systole , occurs just after the P wave (atrial depol)
RA contraction