Chp. 4: Safety Considerations for Laser and Radiographic Procedures and MRI Flashcards
What body parts are at highest risk when using lasers?
Skin and eyes
LASER
Light Amplification by Stimulated Emission of Radiation
True or False: Reflected laser beams are unaltered and contain the same energy as the direct beam.
True.
What laser classes are most common in veterinary medicine?
Class 3b and 4
What is used to characterize lasers?
Wavelength, power, output, tissue exposure time
Can you use the same protective gear for every laser?
No, lasers have differing optical densities
How can you protect an ETT from laser combustion?
Wrap in saline-soaked gauze or sponges
How can fire hazard be minimized during laser procedures?
Spontaneous breathing of room air, lower FiO2, injectable anesthetic techniques, nasotracheal intubation, tracheostomy
List the potential consequences of inhaled laser smoke
Atelectasis, bronchoconstriction, bronchospasm, alveolar edema, interstitial pneumonia, carcinogen exposure
How is ionizing radiation hazardous?
Causes injury at the cellular level by transferring high levels of energy into atoms and molecules such as DNA, RNA, and other cellular proteins, damaging chemical bonds, and altering electrical charge to create free radicals or ions
What cells are most sensitive to the effects of ionizing radiation?
Rapidly dividing cells (bone marrow, reproductive, SI, skin)
What cells are least sensitive to effects of ionizing radiation?
Muscle and nerve
What effects of chronic radiation exposure are anesthesia providers most susceptible to?
Aging, cataracts, SCC, leukemia
How is ALARA achieved?
Increased distance, shielding, decreased exposure time, minimize image number
What is the primary source of personnel occupational exposure to x-rays?
Scatter from the patient (x-rays that bounce or scatter from objects in the path of the primary beam)
What pregnancy time period is most at risk to radiation exposure?
First 16 weeks
How is fetal radiation exposure monitored?
Dosimeter badge at waist under lead
What’s the gestation radiation limit?
10% of normal
Minimum anesthesia/sedation monitoring for radiology
HR, RR and RE, pulse palpation (quality and rate), MM color, NIBP
True or False: The ETT radio-opaque stripe causes CT artifact
True
How is contrast extravasation treated?
Flush area with saline, cold compress, hyaluronidase to increase absorption, symptomatic therapy
How can reduced renal function be reversed after contrast?
Correct hypotension and administer IVF
5-Gauss Line
Line behind which no ferromagnetic objects are allowed
What is the most significant hazard when working in a magnetic environment?
Projectile or missile effect
What implanted materials can be safely imaged with MRI and when?
CV coils and stents, microchips, vascular clamps
Six weeks after placement when there is adequate scarring
How are burns prevented in the magnet?
Lines should run straight (no loops) and parallel to bore, no transdermal patches
Quench
Supercooled liquid gas/cryogen, usually helium, is used to control the energy generated by MR. With a quench, magnetic field is lost and explosion is released through vent pipe under emergency conditions (fire, patient trapped in magnet by missile effect). Frostbite or asphyxiation can occur if vent pipe fails.
ECG in MRI
Gradient magnetic fileds/frequencies can make unreadable
T or ST segment may be elevated due to superimposed voltages generated by aortic blood flow in magnetic field
Carbon graphite patches used
GBCAs
Gadolinium-based contrast agents are excreted predominantly unchanged by the kidneys. Brady or tachycardia, hypo and hypertension can result. Atopic dogs are more likely to have a reaction. Can be given IM if no IV route available.
