Electrical and Environmental Safety Flashcards
Current=
flow of electrical charges or electrons - similar to blood
Circuit=
the path that current flows through - similar to artery or vein
Conductor
current moves easily (copper, bronze)
Insulator
current moves through poorly (glass, air)
Amps=
amount of current flow per second - similar to cardiac output
Voltage
pressure pushing through electrons - similar to contractility
Ohms
measure of resistance (skin- poor conductor, very resistant) - similar to SVR
Hertz
number of cycles per second (HR)
current density
amount of current and area it flows over
How electricity works
A specific amount of alternating current (AC) (amp) is pushed through a circuit by voltage (120v) at a specified frequency (60 Hz
3 wires of the circuit are
-hot- Current
-neutral= return current
-ground= catch leaky/stray current (safety)
Current can only flow through an ____ _____circuit not through an ___ circuit.
-unbroken closed
-open
Ground provides a ____ ____ path for leakage current to flow _____ from electrical equipment
- low resistance
-away
what interrupts the circuit when current flow is high?
circuit breakers
electricity is
energy
current will travel the path of ____ _____
least resistance
frequency is measured in
hertz, 1 HZ = 1 cycle per second
-higher the frequency= the safer
frequencies between 0 HZ and 1 kHZ interferes with:
depolarization and repolarization in myocardium which could cause arrhythmias
minimum current in which fibrillation is induced:
50-60 HZ
Can impedance of current flow happen?
yes
long power cords cause
higher resistance
Human Effects of 60 Hz Currents
1 mA Threshold of perception
5 mA Maximum harmless current intensity
10-20mA “Let go” prevent release of object
50-100 mA Pain, mechanical injury, heart and
resp. function continue.
100-2500 mA Vent. Fib. resp. center intact
>6000 mA Sustained myocardial contraction
resp. paralysis, burns if current
density is high
Macroshock
-current applied directly to body surface
-effects determined by surface area, amt of current flow in amps, duration of exposure, frequency of current, and path
-requires large amt of skin to overcome skins resistance
Macroshock can cause
muscle contraction, pain, burns, open wounds, pacer disruption, arrhythmias
Microshock
Current applied directly to heart
Small amounts of voltage or current applied directly to the myocardium bypassing the skin via a IV catheters, pacer wires, etc
Current as little as ____ microamps can cause fatal arrhythmias
-100
1000 microamps (µA) = 1 milliamp (mA)
1000 milliamp (mA) = 1 Amp
Leakage current is current that escapes the circuit due to stray ____ and poor insulators.
capacitance
capacitance
too much charge built up and current jumps out
What does Line Isolation monitor do
Designed to make it impossible for the patient, and OR staff to become a path for current to go to ground
Line isolation monitors (LIM) measures
how much leakage current would flow to ground if a grounding system were present
-If the electrical equipment being used in the OR allows a large amount of leakage current to escape through its circuitry the LIM will detect it and alarm.
LIM alarm indicates
that current is no longer isolated, an unsafe amount of leakage current may be present
-An LIM alarm usually indicates that the last piece equipment plugged in may have a fault or that too much equipment is being used simultaneously which results in too much leakage current
Electrosurgical Units (ESU) known as ___ and used to:
bovie
-used to cauterize vessels and cut tissue
Bovie uses high frequency of
300kHZ-2MHZ
Unipolar
current applied using a single electrode that returns to the ESU by way of the dispersal pad
bipolar
two pronged cutting electrode instrument. Current travels only between the two prongs
when is it unsafe to use the unipolar
- brain due to nervous system tissue, ovarian, or fallopian tube surgery
Disperal pad (Bovie pad, grounding pad)
applied as close as possible to surgical site, large surface area to minimize current density. Not required for bipolar
Pacemakers and Defibrilators
ESU current traveling through pacer can alter functioning
Precautions for pacemaker use
No unipolar current path through heart.
Dispersal pad close to surgical site as possible
Reducing cautery current or use low current
Use bipolar cautery
Have magnet if pacer requires reprogramming.
Magnet placed on pacer asynchronous mode
Automatic Implantable Cardiac Defibrilators (AICD): actions before surgery?
ESU current will trigger AICD to fire.
Have device turned off prior to surgery
Disinfectants=
antibacterial agent applied to non-living objects. Ex. Santi wipes
Antiseptics
antibacterial agent applied to living tissue. Ex. Chloraprep, betadine
Chemicals in OR and effects on body: Ammonia
disinfectant liquid cleaning agent. Vapors irritate eyes and respiratory tract.
Chlorine Bleach
disinfectant liquid cleaning agents. Vapors irritate respiratory tract.
-never mix ammonia and chloride- lethal
Chlorhexidine
antiseptic used to clean skin. Splashed in eye can cause keratitis or loss of vision
Iodine
antiseptic used on skin. Splashed in eyes can cause irritation
Hydrogen peroxide
antiseptic used to clean skin. Splashed in eyes can cause corneal ulceration
