Diagnostic ultrasound ( PDFDrive )

CHAPTER 56 Pediatric Interventional Sonography 1949
Withdraw
Transducer
cable
Toward
Toward
Ultrasound monitor view
A
B
Think: Do I need to move hub of needle
toward or away from transducer
cable?
Insert
C
D
Toward
cable
E
FIG. 56.7 Changing Needle Angulation. (A) If the needle,
once localized, is not at the correct angle, the needle should be
partly withdrawn. (B) The hub is moved in relation to the position
of the transducer cable. (C) The needle is reinserted at the correct
angle. (D) and (E) The principle of moving the hub in relation to the
transducer cable applies in any position of the transducer-needle
combination.
Initial Puncture Device
Most drainage catheters need to be placed over at least a
0.035-inch-diameter guidewire. An initial puncture with a smallcaliber
needle and placement of a 0.018-inch wire requires an
exchange maneuver, and each passage of a wire or dilator adds
to the time and complexity of the procedure, increasing the risk
of losing position or kinking the wire, especially with most
0.018-inch wires, which are not robust.
Various prepackaged exchange sets are available commercially.
Some sets (i.e., micropuncture, Aprima Access set) have a dilator/
sheath that is placed over the 0.018-inch wire and then the dilator
is removed, leaving the larger sheath in place, which allows
placement of the 0.035-inch wire. hese systems are used for
some biliary procedures or where vital structures are very close
to the target.
he Yueh needle (Cook, Bloomington, IN) is a needle/sheath
device with small holes drilled in the end of the catheter, making