Re: AFI
From: James S Smeltzer MD (gaperina@mindspring.com)
Thu Sep 16 17:45:19 1999
Terry,
The study I posted, by the same authors, showed that infusion of AF reduced
uterine blood flow in oligohydramnios. To then infuse fluid in this setting
is not in the fetal best interest, IMHO.
About fluid, the extremes are associated with bad outcomes. No-one has
shown that the AFI has a better correlation with outcome, to my knowledge,
than any other measure, including seat-of-the pants.
Jim:)
At 04:10 PM 9/16/1999 -0500, you wrote:
>Dr. Smeltzer, as I recall (it has been a long time since I read the original
>article), the article concerned the infusion of fluid when there was none or
>very little in an attempt to minimize Potter's faces and related effects
>(hypoplastic lungs, etc.). As a part of that study, they used the single
>largest pocket and the 4 quadrant method to see which gave the best estimate
>of the amount of fluid they had actually infused. It seems a very good way
>to compare the methods to me.
>
>As far as being ethical, they did not infuse the fluids so they could test
>the measurements, they infused the fluids for other therapeutic reasons due
>to the oligohydramnios. The comparison of the two methods of measurement
>was incidental to the infusion.
>
>Whether or not the infusion of fluids is a valid therapy in these cases is
>another question... and I will leave that to you physicians. However, if
>the infusion is to be done, I see no ethical problem in trying to use
>whatever methods are available to determine how much fluid should be
>infused, has been infused, and to compare the various methods of measurement
>of that fluid.
>
>Terry J. DuBose, M.S., RDMS
>Director, Diagnostic Medical Sonography Program
>CHRP, University of Arkansas for Medical Sciences
>Little Rock, Arkansas, USA
>501-686-6510
>http://www.io.com/~dubose/ <http://www.io.com/~dubose/>
>http://www.uams.edu/CHRP/dmshome.htm <http://www.uams.edu/CHRP/dmshome.htm>
>
>http://www.obgyn.net/us/panel/panel.htm
><http://www.obgyn.net/us/panel/panel.htm>
>
> -----Original Message-----
> From: James S Smeltzer MD [SMTP:gaperina@mindspring.com]
> Sent: Thursday, September 16, 1999 3:44 PM
> To: Multiple recipients of list ULTRASOUND
> Subject: Re: AFI
>
> Terry,
>
> What does this article say about clinical outcome? According to the
> following article, the study you mention is unethical, IMHO:
>
> TITLE: Uterine artery blood flow response to correction of amniotic
>fluid
> volume.
> AUTHORS:Bower SJ; Flack NJ; Sepulveda W; Talbert DG; Fisk NM
> AUTHOR AFFILIATION: Centre for Fetal Care, Royal Postgraduate
>Medical
> School, London, United
> Kingdom.
> SOURCE: Am J Obstet Gynecol 1995 Aug;173(2):502-7 CITATION IDS:
>PMID:
> 7645627 UI: 95373576
> ABSTRACT: OBJECTIVE: Our purpose was to investigate whether acute
> alterations of amniotic fluid volume affect uteroplacental
>perfusion. STUDY
> DESIGN: Three groups of patients of comparable gestational age were
>studied
> in a fetal medicine referral unit: (1) eight pregnancies with severe
> polyhydramnios because of twin-twin transfusion syndrome undergoing
> therapeutic amnioreduction, (2) seven with severe oligohydramnios
> undergoing diagnostic amnioinfusion, and (3) six control women
>having
> invasive procedures of similar duration without manipulation of
>amniotic
> fluid volume. Color Doppler imaging was used to measure uterine
>artery
> impedance index values and quantitative blood flow before and within
>15
> minutes of the end of the procedure. RESULTS: Quantitative flow
> measurements increased after amnioreduction (74% median increase of
>volume
> flow, range 22% to 329%, p < 0.01) and decreased after amnioinfusion
>(33%
> median decrease of volume flow, range 17% to 51%, p < 0.05).
>Impedance
> index values increased after amnioinfusion (25% median increase in
> pulsatility index, range 4% to 71%, p < 0.05) and did not alter with
> amnioreduction. There were no significant changes in the control
>group.
> CONCLUSION: Acute changes in amniotic fluid volume alter
>uteroplacental
> perfusion. In twin-twin transfusion syndrome amelioration in uterine
>flow
> may improve fetal condition and explain in part the success of
>serial
> amnioreduction therapy.
>
> :) Jim Smeltzer, MD
>
> At 02:01 PM 9/11/1999 -0500, you wrote:
> >Dr. Smeltzer, I am not sure I agree with your statement that: "The
> >largest single pocket predates the AFI by decade(s), was never
>shown to
> >be inferior to it...."
> >
> >The following reference was very convincing to me that the AFI is
> >superior to the single largest pocket measurement.
> >
> >"Sepulveda, Flack, & Fisk, using an infusion method in severe
> >oligohydramnios and anhydramnios pregnancies, found that the AFI
> >(4-quadrant sum) was more accurate than the single pocket method."
> >
> >Their methods seem to be a unique and elegant approach to this
>question.
> >
> >Peace, Terry J. DuBose, M.S., RDMS
> >Little Rock, Arkansas USA
> >
> >------------------------
> >
> >------------------------
> >At Wed, 08 Sep 1999, James S Smeltzer MD wrote:
> >------------------------
> >>
> >>Dear Joe,
> >>
> >>The largest single pocket predates the AFI by decade(s), was never
>shown to
> >>be inferior to it, was shown to agree with expert subjective (?!)
> >>assessment & with AFI. We grasp at pseudoquantitative measures to
>provide
> >>a level of truth that lacks, IMHO. There are several older
>studies that
> >>indicate that AF not relevant until truly oligo (<1cm). There is
>a recent
> >>study indicating that Doppler is better predictor than AF in IUGR
>& that AF
> >>measure better than the rest of the BPP for the same purpose.
> >>
> >>My recommendation is to provide referring physicians with
>information that
> >>they can unambiguously use for patient management. For this one
>it would
> >>be AFI - which does encourage a systematic search for fluid. I
>provide a
> >>bottom line clinical impression in all abnormalities of fluid or
>other
> >>measures of fetal status & their clinical significance in the
>setting of
> >>the patient's problems & indications (& in normal ones in which
>measures
> >>are relevant). This is the "interpretation", which constitutes
>the medical
> >>practice part of sonology, IMHO.
> >>
> >>Jim S
> >>
> >>At 12:37 AM 9/4/1999 -0500, you wrote:
> >>> Is amniotic fluid index an outdated technique? Referring
>some articles
> >>>on medline- largest single pocket has replaced AFI- is that
>true? One
> >>>referring doc insisted on AFI-- I have no literature describing
>the
> >>>method. Do you take the total of all four quadrants in cms? or
>is the
> >>>average of largest pockets taken-- ie: divided by 4? Please
>describe
> >>>exactly how to estimate AFI. Regards, DR.JOE ANTONY
> >
> >--
> >Peace, Terry J. DuBose, M.S., RDMS, FAIUM
> >University of Arkansas for Medical Sciences, USA
> >Director, Diagnostic Sonography Program
> >http://www.uams.edu/chrp/dmshome.htm
> >VOICE: 501-686-6510 FAX: 501-686-6513
> >Chair, http://www.obgyn.net/us/us.htm
> >http://www.io.com/~dubose/
> >Now is the time for all good folks to come to the aid of the Earth.
> >
>
