Joy/Krista
Alternatively you could have a look at the following references which
already present false positive value for the CTG in predicting adverse
fetal outcomes:
Nelson KB, Dambrosia JM, Ting TY, Grether JK. Uncertain value of
electronic fetal monitoring in predicting cerebral palsy. The New
England Journal of Medicine 1996;334:613-618.
Nelson KB. The neurologically impaired child and alleged malpractice at
birth. Neurologic Clinics 1999;17(2):283.
MacLennan A. A template for defining a causal relation between acute
intrapartum events and cerbral palsy: international consensus statement.
British Medical Journal 1999;319:1054-1059.
Regards
Declan
Declan Devane,
Doctoral Student / Midwifery Research Assistant,
School of Nursing and Midwifery Studies,
University of Dublin Trinity College,
Trinity Centre for Health Sciences Education,
St. James's Hospital,
Dublin 8.
Tel: 087 659 6923
Email: [log in to unmask]
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-----Original Message-----
From: A forum for discussion on midwifery and reproductive health
research. [mailto:[log in to unmask]] On Behalf Of Kvist
Linda OGHBG
Sent: 16 January 2003 07:03
To: [log in to unmask]
Subject: CTG and PPV
Joy,
You could try to give the descision makers some food for thought by
presenting some pretty convincing statistics.Recruit some help from an
epidemiologist. You need to be able to give the epidemiologist figures
for how many times CTG correctly predicts a negative fetal outcome -
best choice is probably apgar less than 7 at 5 minutes. The
epidemiologist also needs to know approximately how often CTG is used on
a given population of labouring mothers to be.
>From this you can calculate the sensitivity and specificity of CTG
monitoring in labour. You can then go on to calculate the PPV (positive
predictive value) and NPV (negative predictive value). The answers you
get can be translated into understandable terms by something like
this:"How many wrong diagnoses of fetal distress does CTG lead to before
we get a correct diagnosis?" That way we can clearly see the damage we
do even when the intention is to do good. This isn't simple but as far
as I know it's the best way to produce the hard facts that are needed to
get descision makers to sit up. (Unfortunately even this doesn't always
work). Good luck! Linda Kvist.
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