Chapter 6: Patient Care and New Technologies

Question 1

What is distributive shock and what are the 3 types?

Answer 1

When blood vessels lack the ability to constrict and assist in the return of blood to the heart.
Neurogenic: spinal cord injuries, severe pain, meds
Septic:
Anaphylactic:

Question 2

Obstructive shock

Answer 2

Caused by pathologic conditions that interfere with normal pumping action of the heart (ex: PE, pulm htn, tumor, arterial stenosis

Question 3

At what volume loss will hypovolemic shock occur?

Answer 3

15-25%

Question 4

6 steps of the infection cycle

Answer 4

1. infectious agent
2. Reservoir
3. Portal of exit from reservoir
4. Means of transmission
5. Portal of entry
6. Susceptible host

Question 5

Nosocomial infection

Answer 5

hospital-acquired infection

Question 6

Thermal index

Answer 6

A calculation used to predict the maximum temp elevation in tissues as a result of the attenuation of sound. Absorption greater in bone than in soft tissue.
No effects observed for unfocused beam < 100 mW/cm or focused beam < 1W/cm, or temp incrased < 1.5 Celcius

TIS: TI in soft tissue
TIB: TI in bone
TIC: TI in surface bone (ex: cranium)

Question 7

List 3 non-thermal mechanisms

Answer 7

Radiation forces
Streaming
Acoustic cavitation

Question 8

What is cavitation?

Answer 8

The action of an acoustic field within a fluid to generate bubbles.
Stable: bubbles move, but do not expand
Transient: bubble enlarge and collapse (bad)

Question 9

Mechanical index

Answer 9

A nonthermal mechanism developed to assist in evaluating the likelihood of cavitation.
No observed adverse effects if MI < 0.4

Question 10

Elastography

Answer 10

A means of “palpating” tissue with ultrasound to evaluate stiffness.
Used to detect cirrhosis in liver disease

Question 11

Strain elastography vs
acoustic radiation force impulse elastography vs
shear wave elastography

Answer 11

SE: measures the tissue strain, or change in tissue length, as a result of compression. Operator dependent. Qualitative.

ARFI: Similar to SE, but uses acoustic radiation force to compress the soft tissue. Not operator dependent. Qualitative.

SWE: Uses shear waves to analyze the stiffness of the tissue. Quantitative result. (dropping a stone in a pond and measuring the ripples)

Question 12

What is CEUS and what agent is used to accomplish it?

Answer 12

Contrast Enhanced Ultrasound

-A microbubble <10 micrometers is used for the contrast

Question 13

What is sub harmonic imaging?

Answer 13

A technique that images at 1/2 the fundamental frequency in order to suppress the tissue information and better display microvessels.

Question 14

What is fusion imaging?

Answer 14

Real time sonography with simultaneous display of a stored CT or MRI images