0071643192.pdf

■ Cardiac electromechanical dissociation
■ Hydronephrosis
■ Tendons, bursae, cartilage, synovium, synovial fluid, and bone
■ Fetus during routine and emergency prenatal care
■ Foreign bodies in soft tissues or eyes
■ To guide cannulation of vessels, aspirate fluid collections within cavities
(eg, pericardium, pleurae, bladder, or joints), and locate soft tissue foreign
bodies in the skin, soft tissues, or eyes
■ To mark the site for skin puncture or provide continuous real-time visual-
ization throughout a procedure

CONTRAINDICATIONS

■ Lack of sonographic training and experience

TECHNIQUE

■ Lower-frequency probes (3–7 MHz) are used for viewing deeper structures
but produce lower resolution images.
■ Higher-frequency probes (7–20 MHz) are used for viewing superficial
structures and provide higher resolution images.
■ The “gain” controls the amplification of the returning signal. High gain
will cause the image to appear white, low gain will produce dark images.
■ The depth gain control is a set of slide bars that allow you to set indi-
vidual gains (brightness) at different levels.
■ The “magnify” function causes the field to be magnified with the skin sur-
face remaining in the image.
■ The “zoom” function causes the boxed area of interest to be magnified.
Other portions of the image are cut.

COMPLICATIONS

■ Ultrasound is generally considered safe because it does not produce cancer-
causing ionizing radiation. However, prolonged ultrasound causes increased
inflammatory response and heats soft tissue.

INTERPRETATION OFRESULTS

■ Catheters, wires, and needles appear as brightly reflective structures within
fluid-filled anechoic spaces.
■ Arteries and veins appear as anechoic circular structures when viewed in
the transverse plane. Veins are easily compressed, arteries are less easily
compressed, and veins filled with clot are noncompressible.

ORTHOPEDIC PROCEDURES

Extensor Tendon Repairs

INDICATIONS

■ The optimal time for repair of tendons is within 24 hours of injury, but
tendons can be repaired up to 2 weeks later.
■ Zone 4:Area over the dorsal proximal phalanx between the metacarpo-
phalangeal (MCP) and proximal interphalangeal (PIP) joints
■ Zone 5: Tendon (area over the MCP joint) caused by a clean, sharp object
rather than human bite. This area is also often referred to a hand surgeon.
■ Zone 6: Tendon (dorsal hand) injuries

PROCEDURES AND SKILLS

Medical diagnostic ultrasound

uses sound between 3 and 20

MHz (10^6 times per second).

This is above the upper limit

for the human ear to hear

sound of 20 KHz (10^3 times

per second).

Use a low frequency probe to

see deep structures. For

example, a 3.5-MHz probe is

appropriate for a FAST exam.