Hemodynamic monitors & equipment Flashcards
A blood pressure cuff that is too large:
a. falsely increases the blood pressure measurement
b. requires less pressure to occlude the artery
c. increases the risk of radial neuropathy
d. has a bladder width of less than 40 percent of the circumference of the extremity
b. requires less pressure to occlude the artery
A cuff that is too small ___________ SBP
overestimates
A cuff that is too large ______________ SBP
underestimates
The auscultation method of blood pressure monitoring relies on
the Korotkoff sounds
SBP is measured at
the first sound
DBP is measured when
the last sound disappears
The oscillatory method is
as the cuff pressure is released, the monitor measures the pressure fluctuations that occur in response to arterial pulsations
Complications of the oscillatory method include
pain, neuropathy, bruising, measurement errors, compartment syndrome, petechiae, interference with IV medications if IV is distal to the cuff, and limb ischemia
What factors affect the accuracy of the oscillatory method?
bladder size
site of the BP measurement
arm positioning
The ideal length of the bladder is
80% of the extremity circumference
The ideal width of the bladder is
40% of the extremity circumference
For every 10 cm change, the BP changes by
7.4 mmHg
For every 1 inch change, the BP changes by
2 mmHg
At the aortic root, the ______ is the lowest, ______ is the highest, and ______ is the narrowest
SBP; DBP, PP
At the dorsalis pedis artery, the ______ is the highest, the __________ is the lowest, and the ______ is the widest
SBP, DBP, PP
Do not place the BP over
a PICC line, bone fracture, or a limb with an AV fistula
With the oscillometric method, SBP is measured when
oscillations first appear
With the oscillometric method, MAP is measured when
the amplitude of the oscillations is greatest
With the oscillometric method, DBP is measured at
the minimum pressure where oscillations can still be registered
The oscillometric method requires pulsatile flow so a NIBP cuff won’t function in the
patient on cardiopulmonary bypass or with a left ventricular assist device- these patients require an arterial line
Etiologies of an over-dampened arterial line waveform include:
a. air bubbles in the pressure tubing
b. low flush bag pressure
c. improper zero location
d. loss of dicrotic notch
a. air bubbles in the pressure tubing
b. low flush bag pressure
Invasive blood pressure monitors measure BP at the level of _____________________ not __________________
the transducer; not the site of insertion
What effect does an under-damped arterial BP system have on SBP, DBP, and MAP?
SBP: overestimated
DBP: underestimated
MAP: accurate
What effect does an over-damped system have on SBP, DBP, and MAP?
SBP: underestimated
DBP: overestimated
MAP: accurate
What correlates to the peak of the arterial waveform?
systolic BP
What correlates to the trough of the waveform?
diastolic BP
What correlates to the peak value minus trough value of the arterial waveform?
pulse pressure
What correlates to the upstroke of the arterial waveform?
contractility
What correlates to the area under the curve of the arterial waveform?
stroke volume
What correlates to the dicrotic notch of the arterial waveform?
closure of aortic valve
Benefits of intra-arterial BP include
rapid detection of BP fluctuations, more precise titration of vasoactive drugs and easy access for laboratory sampling
Where should the transducer of the arterial BP be placed?
the level of the right atrium
If you’re concerned about measuring cerebral perfusion pressure, you can zero the transducer at
the external auditory meatus (this corresponds to the circle of Willis)
If your a-line is optimally damped, the baseline is re-established after
1 oscillation
If your a-line is under-damped, the baseline is re-established after
several oscillations
Causes of an under-damped waveform include
stiff (non-compliant) tubing and catheter whip (artifact)
If your a-line is over-damped, baseline is re-established with
no oscillations
Causes of an over-damped waveform include
air bubble in the pressure tubing, a clot in the catheter, low flush bag pressure, kinks, and a loose connection
When inserting a central line in the right internal jugular vein, how far should the catheter be advanced to achieve correct placement?
a. 10 cm
b. 15 cm
c. 20 cm
d. 25 cm
b. 15 cm
The tip of the CVP catheter should rest just above
the junction of the vena cava and the right atrium (not inside the RA)
The tip of the PA catheter should reside in the
pulmonary artery, distal to the pulmonic valve (25-35 cm from the VC junction)
Complications of central line placement can occur while
obtaining venous access, during catheter residence or while floating a PA catheter
Accessing the left IJ carries the highest risk of injuring the
thoracic duct (risk of chlyothorax)
__________________ are the most common complication while obtaining access.
Dysrhythmias
Don’t float a PAC in the patient with
a left bundle branch block
The classic presentation of pulmonary artery rupture is
Hemoptysis
The incidence of catheter-related infection increases after
three days
Placing the CVP into the cardiac chambers increases the risk of
dysrhythmias, thrombus formation, and cardiac perforation
How far should you insert a central venous catheter in the right subclavian?
10 cm
How far should you insert a CVC in the left internal jugular?
20 cm
How far should you insert a CVC in the femoral?
40 cm
How far should you insert a CVC in the right median basilic?
40 cm
How far should you insert a CVC in the left median basilic?
50 cm
The best way to treat dysrhythmias as a result of CVC access is to
withdraw the catheter and start over
What patient factors increase the risk of pulmonary artery rupture?
anticoagulation, hypothermia, & advanced age
What provider factors increase the risk of pulmonary artery rupture?
inserting the catheter too far, prolonged balloon inflation, chronic irritation of vessel wall, unrecognized wedging, and filling the balloon with liquid instead of air
What are the complications associated with floating a PA catheter?
pulmonary artery rupture
right bundle branch block
complete heart block (if pre-existing LBBB)
dysrhythmias
What are the complications possible while obtaining venous access?
arterial puncture
pneumothorax
air embolism
neuropathy
catheter knot
