Diagnostic ultrasound ( PDFDrive )

1954 PART V Pediatric Sonography
INF
B
FIG. 56.10 Ultrasound-Guided Transrectal Abscess Drainage. The
needle (arrows) has been inserted through the rectum and has punctured
the high pelvic abscess (A) under ultrasound guidance. The bladder (B)
is anterior to the abscess.
ultrasound-guided transrectal abscess drainage has substantially
replaced the surgical procedure (Fig. 56.10). he catheter can
either be withdrawn ater complete aspiration of the cavity or
let in place and secured to the leg with tape. 3
Peripherally Inserted Central Catheter Lines
Peripherally inserted central catheters (PICCs) are a useful way
of obtaining safe central access for short- to medium-term use. 16
he catheters range from 2 French to 5 French in size, and various
commercial units are available, with insertion sets containing
either a peel-away cannula similar to an intravenous catheter or
a peel-away Seldinger-style sheath.
Ater insertion of the sheath into a peripheral vein (arm, leg,
or scalp), the catheter is placed through the sheath and positioned
in the central veins. Visual access to the arm veins is oten easy
in the older individual, but the veins of corpulent babies and
infants can be notoriously diicult to identify and cannulate.
Ultrasound guidance in these patients has become an essential
skill for the PICC line service, and most PICC line nurses can
successfully be taught the technique. In infants, the technique
of ultrasound guidance for venous access is diferent from previously
described parallel techniques. Because of beam-width issues,
it is best to monitor the needle position by constantly adjusting
the transverse or axial position of the transducer in a sweeping
manner (Figs. 56.11 and 56.12, Video 56.1). he veins are usually
so small that monitoring the needle position with the transducer
in the plane of the needle and vein usually results in malpositioning
of the needle because of the width of the ultrasound
beam.
In older patients with larger veins, scanning in the plane of
the vein can be useful, and safe passage of the guidewire can be
observed (Fig. 56.13).
B
A
A
SUP
Central Venous Access
Placement of long-term central venous access devices is one
of the most common vascular interventional procedures.
Central venous access is used in infectious disease, dialysis,
transplant, and oncology patients. he preferred vein is the
right internal jugular vein (RIJV); it is large, is close to the
skin, and provides a short, straight route to the superior vena
cava. he RIJV should be used whenever possible for dialysis
catheters or in renal failure patients to avoid compromise of
the subclavian veins and the let brachiocephalic vein, which
are important for the success of upper arm surgical dialysis
access. 17 he RIJV also avoids the risk of pneumothorax
and reduces the rate of symptomatic central venous stenoses
when compared with the subclavian vein. 18,19 Use of the RIJV
also avoids catheter pinch-of syndrome, seen exclusively
in subclavian venous access, which is subject to repetitive
trauma in the costoclavicular space and can result in catheter
fracture. 20 When compared with the nonimage-guided surgical
landmark technique (e.g., carotid artery, sternocleidomastoid
muscle), the use of ultrasound has been reported to improve
successful RIJV catheterization and achieves access with
fewer attempts, a reduced incidence of carotid artery punctures,
and increased success rate and a decreased duration of
procedure. 21-25
Ultrasound guidance allows accurate oblique access to the
jugular vein, enabling a smoother curve to the tunneled part of
the central catheter, which minimizes the risk of kinking or
pinch-of obstruction of the catheter.
Pleural and Peritoneal Drainage
Ultrasound-guided diagnostic aspiration of pleural luid is a
common and useful procedure. Simple catheter drainage of
parapneumonic complex luid collection or empyema can result
in complete cure if performed early enough, but the pleura has
a remarkable ability to thicken and produce ibrin. hese infected
collections oten loculate and become diicult to drain using a
simple catheter technique. CT scanning does not usually show
the loculations, and therefore referring clinicians oten believe
that the parapneumonic luid should be easy to drain. he
administration of thrombolytics, typically tissue plasminogen
activator (tPA), through the pleural tube in order to change the
physical characteristics of the thick luid 26,27 is now a routine
procedure. Any chest tube for empyema drainage must be
monitored frequently by radiography, ultrasound, or occasionally
postprocedure CT, to ensure that loculation has not recurred
(Fig. 56.14).
Peritoneal luid drainage for diagnostic and/or therapeutic
reasons is usually not diicult and can oten be achieved at the
bedside with minimal or no sedation and good local anesthetic
technique. When accessing the luid via the lower quadrants,
care must be taken to accurately localize and mark the position
of the inferior epigastric vessels, which can cause substantial
and diicult-to-control bleeding into the peritoneal luid if injured
during an otherwise “simple” aspiration procedure. Occasionally,
debris obstructs the draining catheter and needs to be dislodged,
either by vigorous movement of the needle and catheter or by