Jump to content

JOIN THE DISCUSSION!

Want to join the discussions?

Sign up for a free membership! 

If you are a member already, log in!

(lost your password? reset it here)

99nicu.org 99nicu.org
Schumz

pre and post ductal saturations

Recommended Posts

Hi everyone,

I am quite new to this forum but I really lik ehow the forum and site works. Although it seems quite silly but I need to understand the basics of pre and post ductal saturation what do they actually measure! Blood from the heart or to the heart? Thanks guys!

Share this post


Link to post
Share on other sites

Cardiovascular plumbing :), that's one of my favourite topics!

The pre- and the post-ductal saturations are both arterial saturations (blood from the heart), and refers to arterial oxygen saturation in vessels originating from the aorta before and after the ductal orifice in the aorta.

Classically, the pre-ductal values are recorded in the right hand, but one can argue that left-handed saturations are roughly the same (http://www.biomedcentral.com/content/pdf/1471-2431-10-35.pdf).

Arterial post-ductal sat's are measured in the foot.

Post-ductal saturations become lower than pre-ductal when there is mixing of pulmonary blood through the duct, i.e. in congenital heart defects that are duct dependent. For example, severe coarcations or transpositions of the great arteries typically have lower postductal sat´s.

This is the theoretical background to POX screening (http://www.bmj.com/content/338/bmj.a3037.full)

  • Like 1

Share this post


Link to post
Share on other sites

Pre-ductal and post-ductal pulse O2 saturation (SpO2) monitors (to detect R → L

shunting at ductus arteriosus). A difference of ≥10% suggests marked pulmonary

hypertension or PDA dependent leison.

Pre-ductal and post-ductal pulse O2 saturation (SpO2) can be used as screening for cyanotic heart disease for NB befor discharge hom fro postnatal ward.

Share this post


Link to post
Share on other sites

In the strange scenario of post ductal SpO2 being more than the Pre-ductal SpO2, think of TGA with PPHN.

Share this post


Link to post
Share on other sites

I wonder if there are any more common states where you would find reversed pre- and postductal saturations? We see it sometimes and those children do not have serious congenital heart defects such as TGA. Right now I´m looking at one baby with 95% foot 86% right hand.

Any experience on this?

Share this post


Link to post
Share on other sites

We do see sometimes such reversed pre/post ductal saturations in our NICU in children without any heart defect. It is usually below 5%.

Unfortunately I haven't find any explanation yet.

Share this post


Link to post
Share on other sites
On 2/23/2019 at 5:11 AM, Urban Rosenqvist said:

I wonder if there are any more common states where you would find reversed pre- and postductal saturations? We see it sometimes and those children do not have serious congenital heart defects such as TGA. Right now I´m looking at one baby with 95% foot 86% right hand.

Any experience on this?

I know this is not what you mean, but the single most common cause of this phenomenon in my experience is actually reversal of the probes (ie the pre- and post- are mislabeled/swapped).

 

But, yes, I have seen several cases of the actual physical phenomenon you describe, often self resolved in a short period of time and sometimes causing an annoyed call from a cardiologist asking why I got an ECHO

Share this post


Link to post
Share on other sites

Can we diagnose PPHN fairly confidently by this procedure to start Sidenafil

Share this post


Link to post
Share on other sites

bimc

On ‎3‎/‎13‎/‎2019 at 6:37 AM, bimalc said:

I know this is not what you mean, but the single most common cause of this phenomenon in my experience is actually reversal of the probes (ie the pre- and post- are mislabeled/swapped).

 

But, yes, I have seen several cases of the actual physical phenomenon you describe, often self resolved in a short period of time and sometimes causing an annoyed call from a cardiologist asking why I got an ECHO

Good point though. I will check for mislabeled/swapped probes in the future... 

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

×
×
  • Create New...