PAD/Wedge pressure measurement

CVP is being displayed as a mean on most monitors. There is
no "correction" for this with regards to inspiration on the
Marquette's or Hewlett Packard/Agilent product.. other than
the averaging function associated with obtaining the mean.

With regards to PA pressures, no.. the monitor (again, HP
and Marquette) doesnt automatically distingish between
inspiration and expiration in displaying the values. How do
you know? Well, you dont have a mechanism to tell the
monitor that the patient is recieving positive pressure
ventilation, which directly impacts how you read PCWP.
Remember, end expiration on a non-ventilated patient is
"highest" and on a positive pressure ventilated patient it
is the "lowest" value on the PA tracing.

So.. No.. the machine doesnt correct for inspiration. In the
vast majority of patients there is minimal effect on PA, ART
and CVP pressures by respiration (unless they are coughing),
so just chart the value at any given moment.

Dave

terrie said:

I understand that PCWP measurements need to be taken at
the end of expiration. Does this also apply to taking PAD
and CVP pressures?

Are monitors that display pulmonary artery systolic and
diastolic pressures able to automatically display these
values at end of expiration?

Thanks,

Terrie

Dave S said:

CVP is being displayed as a mean on most monitors. There
is no "correction" for this with regards to inspiration
on the Marquette's or Hewlett Packard/Agilent product..
other than the averaging function associated with
obtaining the mean.

With regards to PA pressures, no.. the monitor (again, HP
and Marquette) doesnt automatically distingish between
inspiration and expiration in displaying the values. How
do you know? Well, you dont have a mechanism to tell the
monitor that the patient is recieving positive pressure
ventilation, which directly impacts how you read PCWP.
Remember, end expiration on a non-ventilated patient is
"highest" and on a positive pressure ventilated patient it
is the "lowest" value on the PA tracing.

So.. No.. the machine doesnt correct for inspiration. In
the vast majority of patients there is minimal effect on
PA, ART and CVP pressures by respiration (unless they are
coughing), so just chart the value at any given moment.

Dave

Would concur :-)

Servant to the humblest person in the universe,

Andrew

--
Dr. Andrew B. Chung, MD/PhD
Board-Certified Cardiologist
heartmdphd.comheartmdphd.comOpen ↗

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What is all this about?
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Wow.. we all like being validated from time to time.

Dave

Dr. Andrew B. Chung said:

Dave S said:

CVP is being displayed as a mean on most monitors. There
is no "correction" for this with regards to inspiration
on the Marquette's or Hewlett Packard/Agilent product..
other than the averaging function associated with
obtaining the mean.

With regards to PA pressures, no.. the monitor (again, HP
and Marquette) doesnt automatically distingish between
inspiration and expiration in displaying the values. How
do you know? Well, you dont have a mechanism to tell the
monitor that the patient is recieving positive pressure
ventilation, which directly impacts how you read PCWP.
Remember, end expiration on a non-ventilated patient is
"highest" and on a positive pressure ventilated patient it
is the "lowest" value on the PA tracing.

So.. No.. the machine doesnt correct for inspiration. In
the vast majority of patients there is minimal effect on
PA, ART and CVP pressures by respiration (unless they are
coughing), so just chart the value at any given moment.

Dave

Would concur :-)

Servant to the humblest person in the universe,

Andrew

--
Dr. Andrew B. Chung, MD/PhD Board-Certified Cardiologist
heartmdphd.comheartmdphd.comOpen ↗

** Who is the humblest person in the universe?
makeashorterlink.commakeashorterlink.comOpen ↗

What is all this about?
makeashorterlink.commakeashorterlink.comOpen ↗

Is this spam? makeashorterlink.commakeashorterlink.comOpen ↗

Dave S <[email hidden]> wrote in message news:<[email hidden]>...

Quoted message said:

CVP is being displayed as a mean on most monitors. There
is no "correction" for this with regards to inspiration
on the Marquette's or Hewlett Packard/Agilent product..
other than the averaging function associated with
obtaining the mean.

With regards to PA pressures, no.. the monitor (again, HP
and Marquette) doesnt automatically distingish between
inspiration and expiration in displaying the values. How
do you know? Well, you dont have a mechanism to tell the
monitor that the patient is recieving positive pressure
ventilation, which directly impacts how you read PCWP.
Remember, end expiration on a non-ventilated patient is
"highest" and on a positive pressure ventilated patient it
is the "lowest" value on the PA tracing.

So.. No.. the machine doesnt correct for inspiration. In
the vast majority of patients there is minimal effect on
PA, ART and CVP pressures by respiration (unless they are
coughing), so just chart the value at any given moment.

Dave

I thought that the effect of respiration on a non-ventilated
patient would be a variation of about 10mm in pressure. Is
this about right?

Isn't it necessary to verify that in a non-ventilated
patient you are recording the highest pressure value in the
respirtory cycle, or you numbers may be way off(recording a
pcwp of 10 rather than 20)?

Terrie

If you noticed, my closing paragraph omitted mention of
the wedge when saying to "ignore resps".. it addressed
cvp, abp and pa, NOT pcwp. So you and I are both correct,
and I apologise for not being more specific in reinforcing
that point.

Dave

terrie said:

Dave S <[email hidden]> wrote in message news:-
<[email hidden]>...

Quoted message said:

CVP is being displayed as a mean on most monitors. There
is no "correction" for this with regards to inspiration
on the Marquette's or Hewlett Packard/Agilent product..
other than the averaging function associated with
obtaining the mean.

With regards to PA pressures, no.. the monitor (again, HP
and Marquette) doesnt automatically distingish between
inspiration and expiration in displaying the values. How
do you know? Well, you dont have a mechanism to tell the
monitor that the patient is recieving positive pressure
ventilation, which directly impacts how you read PCWP.
Remember, end expiration on a non-ventilated patient is
"highest" and on a positive pressure ventilated patient it
is the "lowest" value on the PA tracing.

So.. No.. the machine doesnt correct for inspiration. In
the vast majority of patients there is minimal effect on
PA, ART and CVP pressures by respiration (unless they are
coughing), so just chart the value at any given moment.

Dave

I thought that the effect of respiration on a non-
ventilated patient would be a variation of about 10mm in
pressure. Is this about right?

Isn't it necessary to verify that in a non-ventilated
patient you are recording the highest pressure value in
the respirtory cycle, or you numbers may be way
off(recording a pcwp of 10 rather than 20)?

Terrie

Hi Dave,

I'd still be interested to know why you think ignoring
respiration is ok for measuring pa and cvp. I would think
you would get the same ~10mm difference in pressure
between inspiration and expiration and that would not be a
minimal effect.

Terrie

Dave S <[email hidden]> wrote in message news:<_-
[email hidden]>...

Quoted message said:

If you noticed, my closing paragraph omitted mention of
the wedge when saying to "ignore resps".. it addressed
cvp, abp and pa, NOT pcwp. So you and I are both correct,
and I apologise for not being more specific in reinforcing
that point.

Dave

terrie said:

Dave S <[email hidden]> wrote in message
news:<[email hidden]-
.net>...

Quoted message said:

CVP is being displayed as a mean on most monitors. There
is no "correction" for this with regards to inspiration
on the Marquette's or Hewlett Packard/Agilent product..
other than the averaging function associated with
obtaining the mean.

With regards to PA pressures, no.. the monitor (again,
HP and Marquette) doesnt automatically distingish
between inspiration and expiration in displaying the
values. How do you know? Well, you dont have a mechanism
to tell the monitor that the patient is recieving
positive pressure ventilation, which directly impacts
how you read PCWP. Remember, end expiration on a non-
ventilated patient is "highest" and on a positive
pressure ventilated patient it is the "lowest" value on
the PA tracing.

So.. No.. the machine doesnt correct for inspiration. In
the vast majority of patients there is minimal effect on
PA, ART and CVP pressures by respiration (unless they
are coughing), so just chart the value at any given
moment.

Dave

I thought that the effect of respiration on a non-
ventilated patient would be a variation of about 10mm in
pressure. Is this about right?

Isn't it necessary to verify that in a non-ventilated
patient you are recording the highest pressure value in
the respirtory cycle, or you numbers may be way
off(recording a pcwp of 10 rather than 20)?

Terrie

The other values arent impacted as much by the tidaling
of intrathoracic pressures.. when they are.. that means
something else is going on. Pulsus Paradoxus for
instance, when you have a greater than 10mm/hg variance
in your arterial pressure due to respirations, is an
abnormal finding.

I agree that the CVP is on the "more variable" end of things
with regards to respirations (in that its a filling
pressure, like the wedge
is) but I cant ever recall a nurse freezing a tracing and
manually reading a CVP to the end-expiratory point like
one does with a wedge pressure.

Dave

terrie said:

Hi Dave,

I'd still be interested to know why you think ignoring
respiration is ok for measuring pa and cvp. I would think
you would get the same ~10mm difference in pressure
between inspiration and expiration and that would not be a
minimal effect.

Terrie

Dave S <[email hidden]> wrote in message news:-
<[email hidden]>...

Quoted message said:

If you noticed, my closing paragraph omitted mention of
the wedge when saying to "ignore resps".. it addressed
cvp, abp and pa, NOT pcwp. So you and I are both correct,
and I apologise for not being more specific in reinforcing
that point.

Dave

terrie said:

Dave S <[email hidden]> wrote in message news-
:<[email hidden]>...

>CVP is being displayed as a mean on most monitors. There
>is no "correction" for this with regards to inspiration
>on the Marquette's or Hewlett Packard/Agilent product..
>other than the averaging function associated with
>obtaining the mean.
>
>With regards to PA pressures, no.. the monitor (again,
>HP and Marquette) doesnt automatically distingish
>between inspiration and expiration in displaying the
>values. How do you know? Well, you dont have a mechanism
>to tell the monitor that the patient is recieving
>positive pressure ventilation, which directly impacts
>how you read PCWP. Remember, end expiration on a non-
>ventilated patient is "highest" and on a positive
>pressure ventilated patient it is the "lowest" value on
>the PA tracing.
>
>So.. No.. the machine doesnt correct for inspiration. In
>the vast majority of patients there is minimal effect on
>PA, ART and CVP pressures by respiration (unless they
>are coughing), so just chart the value at any given
>moment.
>
>Dave
>

I thought that the effect of respiration on a non-
ventilated patient would be a variation of about 10mm in
pressure. Is this about right?

Isn't it necessary to verify that in a non-ventilated
patient you are recording the highest pressure value in
the respirtory cycle, or you numbers may be way
off(recording a pcwp of 10 rather than 20)?

Terrie