Equipment
The necessary equipment for an abdominal
paracentesis is usually available as a packed,
sterilized set.
Antiseptic—povidone-iodine solution
Local anesthetic—lidocaine hydrochloride
Sterile syringes and plungers—a 10-ml syringe is
used to administer the anesthetic. A 30 or 50-ml
syringe is used to collect the specimen
Disposable needles—25- and 22-gauge needles are
usually used when administering the anesthetic
Intravenous catheter—a 20- or 22-gauge catheter
with trocar is preferred
Three-way stopcock
Sterile tubing—two 30-50 cm lengths tubing may be
needed
Specimen containers
Sterile adhesive bandage
Procedure
1. Have the patient empty his and her bladder.
2. Place the patient in the semirecumbent position.
3. Identify the puncture site - the avascular midline
caudad to the umbilicus and caudad to the level
of percussible dullness. Avoid surgical scars. If
a midline scar is present, use a site in the lower
abdomen 1-2 cm lateral to the margin of the
rectus sheath. Use the side which is more dull
to percussion. If the volume of peritoneal fluid
is small, such that dullness to percussion can be
demonstrated only when the patient is in the
hands-knee position, the patient should undergo
the procedure in that position. If the patient is
too weak to maintain the position, place the
patient in the prone position spanning two beds,
and perform the procedure sitting on the floor.
4. Cleanse the skin over the puncture site using the
antiseptic. Allow it to air dry. The remainder
of the procedure is performed using sterilized
equipment and sterile technique.
5. Infiltrate the skin and soft tissue at the puncture
site with 5 ml of the anesthetic. Use the
25-gauge needle for the skin and the 22-gauge
needle for the soft issue.
6. Retract the skin at the puncture site toward the
symphysis and insert the trocar with catheter.
Hold the trocar perpendicular to the abdominal
wall. Advance the trocar into the peritoneal
cavity. When fluid appears in the catheter
tubing remove the trocar while keeping the
catheter in place. Attach a length of tubing to
the catheter hub and the large syringe to the free
end of the tubing.
7. Withdraw adequate fluid to perform the desired
studies.
8. If a large volume of fluid is to be removed, insert
the stopcock into the free end of the tubing.
Attach the large syringe and the other length of
tubing to the stopcock. Aspirate fluid into the
syringe then expel it through the open tubing.
9. Remove the catheter. Apply direct pressure to
the puncture site.
10. Apply a sterile adhesive bandage.
Sources of Variability
1. Incision of a vessel can lead to contamination of
the peritoneal fluid specimen with blood. The
volume of fluid is usually so large that such
contamination has little effect upon the labora-
tory studies. However, this possibility must be
kept in mind if the study values are at variance
with the clinical impression.
Medical Considerations
1. The performance of an abdominal paracentesis in
a patient with a hemorrhagic diathesis is associ-
ated with a significant risk of serious abdominal
wall or intraperitoneal hemorrhage. Because of
this risk, this setting is a relative contraindica-
tion for a paracentesis. The procedure can be
made much safer by therapeutic correction of the
bleeding disorder, if possible.
2. Perforation of bowel is unusual if the bowel is
mobile. Even if punctured, the bowel usually
does not leak its contents. Peritonitis can
develop, however, so closely monitor any
patient who suffers a bowel perforation during
paracentesis. The chance of puncturing the
bowel is minimized by not selecting a puncture
Specimen Collection Procedures A-10
PERITONEAL FLUID
