| Procedure Name Ultrasound, Amniocentesis
Synonyms Amniocentesis
Ultrasound
Procedure Commonly Includes Locating appropriate
puncture site for amniocentesis and subsequent performance of
amniocentesis under direct visualization.
Indications Used in the last
two trimesters of pregnancy to determine post maturation,
deformities, Rh incompatibility, amniotic fluid bilirubin
level, amniotic fluid L/S ratio, amniotic fluid-fetoprotein
level, and genetic malformations
Contraindications
Inadequate amount of fluid, anterior placenta, presence of
fetal vertex or trunk in needle path
Patient Preparation
The examination may be long, up to 1 hour including waiting
time. An emergency examination or an unpredictably long
preceding examination may result in additional delay. Note:
Each Rh-negative unsensitized woman whose husband is not known
to be Rh-negative should receive Rh immune globulin.
Special Instructions
Patient is brought to Radiology and the procedure is performed
by a radiologist or obstetrician with the aid of ultrasound.
Patient is required to stay in the hospital for a few hours for
precautionary measures.
Complications Pain,
amnionitis (infection), abortion, hemorrhage, trauma to fetus,
rupture of membranes, placental or subchorionic hematoma, Rh
sensitization, premature labor, abruptio placenta, maternal
death
Equipment Standard B-mode real
time ultrasonic imager with 2-5 MHz transducer. Biopsy guide if
desired; 20- or 22-gauge spinal needle.
Technique Under ultrasound
guidance, an appropriate location is found to insert a small
needle into the amniotic fluid. The skin is marked
appropriately and prepared for placement of the needle using
sterile technique. Needle is placed and amniotic fluid
aspirated.
Data Acquired Images of area
to be sampled
Specimen Amniotic fluid
Causes for Rejection
Patient not able to tolerate exam
Turnaround Time A typed
report will generally be issued within 36 hours. A preliminary
verbal report generally can be given to the referring physician
on request.
Normal Findings Successful
aspiration of adequate amount of amniotic fluid
Limitations Amniotic fluid not
obtainable due to placenta location or lack of suitable
puncture site, little or no amniotic fluid available for
amniocentesis
References:
Platt LO, Hill LM, DeVore GR, et al, "Amniocentesis:
Current Concepts and Techniques,"The Principles and
Practice of Ultrasonography in Obstetrics Gynecology,
Sanders and James, eds, Norwalk, CT: Appleton-Century-Crofts,
1985.
|
