Re: Collecting reaserch data

[Jerry Zion <jerryz@protocol.com>]

When comparing Propaq NIBP measurements against a manual reading there
are several items that will be expected to vary:

1.  Were measurements taken on the same limb at 2 different times?
	The literature shows that readings taken at different times even using
the same
	limb will vary in pressure.  The literature also shows that when making
this type
	of comparison, but using different technologies (automated
oscillometric monitor vs
	aneroid gauge and stethoscope) the differences between the technologies
may add to
	the variance between the resulting readings.  Oscillometry detects and
measures the 
	MEAN pressure in the cuff, then calculates the Systolic and Diastolic
readings.
	When you auscultate the cuff blood pressure, you estimate the Systolic
and Diastolic
	pressures based on the Karotkoff sounds, and then you calculate the
MEAN pressure.
	It also makes a difference whether one uses the 1st or 5th Karotkoff
sound to make 
	the blood pressure estimate.  While I have used the term "estimate"
here, let me
	be clear that such an estimate is usually very accurate.  The
literature supports
	all of this.

2. Were measurements taken on different limbs (right and left arms,
right and left legs)?
	The literature shows that readings taken on different limbs vary.  The
same comment
	applies here regarding different technologies.

So how can a user in the field feel satisfied that the Propaq is
calibrated and providing
appropriately accurate readings?
	Propaq oscillometric NIBP was compared against invasive blood pressure
readings
	in a variety of use settings and patient age groups in order to obtain
market
	clearance by the FDA.  The design and manufacturing process continue to
be
	audited to ensure that we have not "lost the formula".	

	The Propaq Service Manual provides instructions for a Biomedical
Technician or
	Engineer to verify the static calibration of the NIBP measurement
system.  This
	procedure can be performed whenever users feel the monitor is not
providing 
	accurate measurements, and has not displayed an equipment alert message
or other
	error code indicating that Propaq needs service.  

	Welch Allyn Protocol always 
	verifies calibration after any repair to the Propaq, especially those
having to
	do with NIBP.  Biomedical Departments performing repairs should follow
this
	practice.	

	The clinician can use the electronic manometer (displayed on the NIBP
screen of the 	Propaq) to auscultate the blood pressure systolic and
diastolic sounds while the
	monitor is making it normal measurement.  Your results should agree
with the monitor 
	within the specified accuracy band for NIBP measurements.

To ensure accurate readings when faced with motion artifact, use a
Propaq Encore or Propaq CS monitor with Smartcuf NIBP.  This specialized
algorithm makes use of the ECG waveform to
identify the pressure wave in the cuff most closely associated with the
contraction of the heart that produced it.  That way the motion artifact
can be ignored.  Except when arrhythmia is also present, this algorithm
is producing some exciting results in everyday Air Medical Transport
use.  Please feel free to contact Becky Fee, CFRN LifeFlight Network,
Portland, OR or Renee Holleran, RN PhD of Cincinnati AirCare.  Both have
experience with usind it.

Jerry Zion, CBET, MS
Welch Allyn Protocol, Inc. 

MIKE SMITH wrote:
> 
> Jerry,
> 
> All I'm looking for is whether your monitor is calibrated against some sort
> of control.  One of our Propac's worked as normal however, compared to a
> manual pressure it measured any where from 30 - 60 mmHg off.  Is that
> calibrated?  Could that cause a problem with a patient?  What if you were
> using vasoactive drugs?
> 
> So, all I'm interested in is ... does your machine get calibrated?
> 
> Thanks,
> Mike Smith
> ----- Original Message -----
> From: Jerry Zion <jerryz@protocol.com>
> To: <flightmed@flightweb.com>
> Sent: Monday, May 21, 2001 02:16 PM
> Subject: Re: Colecting reaserch data
> 
> > To the question, "how often has your NIBP monitor been calibrated",
> > would it not be important to know how often the manufacturer of your
> > NIBP monitor says it should be calibrated?  Consider the Propaq.  The
> > equipment alert tells you when service (including calibration) is
> > required.  It calibrates itself everytime the monitor is turned on.  If
> > it cannot calibrate, it then tells you (via an equipment alert or error
> > message) that it's time for a repair.  Other devices (monitors and
> > manometers) don't do this, and therefore have a required periodic
> > re-calibration specified by the manufacturer.
> >
> > Jerry Zion, CBET, MS
> > Welch Allyn Protocol, Inc.
> >
> > MIKE SMITH wrote:
> > >
> > > Hello,
> > >
> > > I am collecting data for a research project. If you could answer these
> > > questions and e-mail them back directly to me as not to clog the list
> with
> > > this thread.
> > >
> > > Thanks, Michael D. Smith
> > > msmith@grandviewheights.org
> > >
> > > Survey
> > >
> > > Name of Department/Service:
> > >
> > > City/State:
> > >
> > > ALS BLS:
> > >
> > > Do you use pulse SpO2?
> > >
> > > Do you use NiBP?
> > >
> > > Do you use hands off Defib?
> > >
> > > Do you have a policy or protocol regarding use of NiBP?
> > >
> > > Do you use manual BP measurement with NiBP?
> > >
> > > Do you use NiBP as your sole source of blood pressure measurement?
> > >
> > > How often has your NiBP monitor been calibrated?
> > >
> > > _______________________________________________
> > > Flightmed mailing list
> > >
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> > > Flightmed mailing list
> >
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