How to Set-up a Pressure Transducer for CVP and A-lines

How to Set-up a Pressure Bag

Welcome to the Pressure Bag Set-up Site:We’ll make it so easy even
an EM resident can do it.
Get a 500 cc bag of Normal Saline.
Get a pressure monitoring set-up pack.They’re in the Cardiac and
Trauma Rooms.
Get a pressure bag.
Open the pressure monitoring kit. Don’t throw away the little bag of
yellow and white caps you’ll find inside; you’ll need them later.
From this point on, try to keep anything that is in contact
with the saline sterile. Pull out the spike tab from the bag of saline.
Spike the bag with the pressure tubing spike.

find a white tab on the tubing; when you squeeze it, it allows saline to
flow through the tubing. Don’t squeeze it yet, just find it.
Turn the bag upside down. See all that air in the bag of saline;
getting that air into the patients blood stream is in medical parlance,
bad. You need to get rid of it. The way to do it is to squeeze the bag
gently, while maneuvering the air into the spike and therefore into the
drip chamber. You must do this while simultaneously squeezing the white
tab we mentioned in the previous frame. You’ll never get all of the air,
but try to get as close as you can without injecting saline into the
drip chamber.
Now insert the saline bag into the pressure bag.
Hang that bad boy on an IV pole.
Squeeze the drip chamber until it is half-filled with saline.
Now squeeze the white tab until saline spurts out of the white
stopcock cap immediately adjacent. There should be no air bubbles
between the drip chamber and this stopcock cap. If there are, squeeze out
some more saline using the white tab.
Each stopcock cap has an associated stopcock. Turn said stopcock
until it is pointed towards the stopcock cap.
There is another white stopcock cap lower down on the pressure
tubing. Squeeze the white tab until saline spurts out of this one as
well. Check to make sure there are no air bubbles.
Turn the stopcock of this cap so it faces the cap. Squeeze the white
tab until saline spurts out of the most distal portion of the tubing.
This endpoint also has a white cap. Check the entire tubing to make sure
there are no air bubbles. Air bubbles are your enemy; hate them as they
hate you.
Now replace each of those three white caps with yellow caps. The
yellow caps are in the little bag I told you to save at the beginning of
this tutorial. Go to the garbage bin and retrieve this little bag. Don’t
worry it’s sealed; in pressure bagging, unlike in life, you get a 2nd
chance. Do try to be sterile about this. The bag is now set to wait until
you need it. Just leave it set up like this in a state of vigilant
When ready to use, pressurize the pressure bag until the
gauge reads
300 mm Hg. It works just like a BP cuff; if it is not inflating, it is because
you did not turn the knob all the way clockwise. Clamp the white clampy
thing when you are at 300.
Halfway there
Ahh! 300, just like I told you. The line may now be plugged into an
a-line catheter or the distal port of a central line for CVP.
Each monitor in cardiac/trauma has a pressure line module.
from this module is a gray wire. Plug this wire into the telephone
cord-like thingie that emerges from the pressure tubing adjacent to the
white tab.
Here is a shot of said telephone-like doohickie.
The X in the photo marks the spot of the PHLEBOSTATIC AXIS. You must
position the stopcock (the one adjacent to the white tab) at this point. Use tape
to secure the tubing to the chest so that the stopcock is at this point.
If you do this right, then you will not need to re-level the pressure line when
the patient is moved.

Now you’re ready to zero the line (pretend the portion shown in the
photo is properly affixed to the patient’s armpit as shown in the
diagram above.) You must remove the
yellow cap from the stopcock. Turn the stopcock until the line is CLOSED
OFF TO THE PATIENT. Squeeze the white tab to let a little saline spurt
out of the now open stopcock. If the saline does not spurt you closed
the stopcock the wrong way.
Press the pressure button on the pressure monitoring monitor insert
(I’m having fun, are you?)
The screen should now have a tab which says “Zero Something”. Press
the button immediately below this (arrow) two times.
The screen should now read line zeroed and then the date and time,
all official-like. You may choose to write this date and time down in a
little notebook you carry for just such purpose.
Put the yellow cap back on and turn the stopcock back towards the
What happens the monitor shows CVP but you want ABP? What if the scale is wrong?The following will show you how to change the onscreen displays for CVP/ABP/ICP.
Press the pressure button on the actual module you want to change.
Now you can change the scale. Obviously 180 is too high for CVP measurements.
To change the label, press “Change Label”. See how dummy-proof this is?
Now you can change it to whichever label you want (most likely CVP/ABP.All zeroing is the same so changing scale/label does not require re-zeroing.
Exalt in the glory of the pressure wave, which now appears on the


Leave a Reply