J'ai de la difficulté à gober les chiffres cités dans le BMJ. Je
trouve l'approche de Rosen sensée. Dans le BMJ, on cite une "étude
locale" qui a mené à des recommandations. Quelqu'un a-t-il des
réponses de nos nucléistes "locaux"?
Bernard Mathieu, MD
Le 08-01-16 à 11:15, Martin Pham Dinh a écrit :
Je ne suis pas convaincu que Rosen est à jour. Du moins, voici des
références qui indiquent clairement que le CT offre une irradiation
foetale moindre par rapport au V/Q
http://www.bmj.com/cgi/content/full/331/7512/350?etoc
http://bjr.birjournals.org/cgi/content/abstract/79/941/441
http://radiology.rsnajnls.org/cgi/content/full/240/3/765
Je commence toujours par un doppler car si +, pas besoin
d'investigation supplementaire.
Martin Pham Dinh
[EMAIL PROTECTED]
De : [email protected] [mailto:[EMAIL PROTECTED] De la part de
Alain Vadeboncoeur
Envoyé : January 16, 2008 10:38 AM
À : [EMAIL PROTECTED]
Objet : URG-L: CT ou VQ
Rosen donne des idées intéressantes sur ce sujet:
How can I rule out pulmonary embolism in a pregnant patient without
use of ionizing radiation? PE is the most common nontraumatic cause
of death in pregnant women, so clinicians are justified to adopt a
liberal “rule-out PE” approach to all pregnant women with dyspnea.
Pulmonary V/Q scanning is safe in pregnancy and provides almost no
risk to the fetus. A chest CT scan delivers about 250 mrad of
energy, whereas the common threshold at which fetomaternal experts
believe fetal teratogenicity becomes a concern is about 5 rad. The
mother's abdomen can be shielded, but the fetus will still receive a
small fraction of the 250 mrad. There is a rapidly growing body of
literature that suggests that exposure of the young brain to even
small amounts of radiation can produce subtle cognitive deficits
later in life, and at present the long-term consequences of CT
scanning of pregnant patients are unknown. It seems logical to try
to rule out PE with the D-dimer in pregnant patients; if D-dimer is
negative in a patient believed to be at low pretest probability,
this excludes the diagnosis. Coagulation systems are hyperactive in
pregnancy, elevating the circulating D-dimer concentration. The D-
dimer concentration increases linearly with duration of normal
pregnancy, and about 75% of all pregnant patients evaluated for PE
have a D-dimer concentration greater than the abnormal cutoff of 500
ng/mL.[46] About 60% of healthy pregnant patients have a D-dimer
less than 1000 ng/mL, however, and virtually all pregnant patients
with a PE have a D-dimer greater than 1000 ng/mL. A reasonable
interpretation of these data suggests the following approach. If the
D-dimer concentration is less than 1000 ng/mL, and the patient meets
the criteria in Box 87-2 , the diagnosis of PE may be considered
reasonably excluded, and pulmonary vascular imaging is not
necessary. As an additional margin of safety, a negative venous
ultrasound of the lower extremities excludes DVT and helps reduce
the probability of PE by about half. V/Q scanning, if normal,
excludes the diagnosis. A high-probability V/Q scan establishes the
diagnosis, and heparin (which does not cross the placental barrier)
can be initiated. If neither normal nor high probability, the V/Q
scan is nondiagnostic, and further imaging (perhaps beginning with
venous duplex ultrasound of the legs) is indicated.
Alain Vadeboncoeur
No virus found in this incoming message.
Checked by AVG Free Edition.
Version: 7.5.516 / Virus Database: 269.19.5/1228 - Release Date:
16/01/2008 9:01 AM
No virus found in this outgoing message.
Checked by AVG Free Edition.
Version: 7.5.516 / Virus Database: 269.19.5/1228 - Release Date:
16/01/2008 9:01 AM
