10-10a Intro to Clinical Uses of Electrotherapy I Flashcards
What are the uses of Estim?
Neuromuscular dysfunction – NMES/FES
Pain - TENS
Wound/tissue healing - HVPC
Delivery of Pharmacological agents – Iontophoresis
Electric Muscle Stimulation (denervation) – EMS
Edema management
Evaluate nerve and muscle injury - NCV testing
What are the uses of Estim?
Neuromuscular dysfunction – NMES/FES (used to get stronger/improve m. control)
Pain - TENS
Wound/tissue healing - HVPC
Delivery of Pharmacological agents – Iontophoresis
Electric Muscle Stimulation (denervation) – EMS
Edema management
Evaluate nerve and muscle injury - NCV testing
What are the three types of electrical currents?
Direct Current, Alternating Current, and Pulsatile Current
What is DC?
Uninterrupted flow of charged particles
Moves from negative to positive
What is AC?
Flows from positive to negative repetitively without breaks
What is pulsatile current?
Space between the pulses
Monophasing (all positive) or biphasing (like alternating current: positive and negative
What are the three uses of Estim?
sensory (pain), motor (pain and strengthening), noxious (pain)
What is charge measured in?
Coulombs
What is Current measured in?
Amperes
What is voltage measured in?
volts
What is resistance measured in? What is it for?
ohms
DC
What is impedence measured in? What is it for?
ohms
alternating current/pulse current
What is capacitance? measured in?
Farads
What makes copper conductive?
metals with one valence electron can share their one valence electron easily
What does charge do to the body?
Provide charge on either end of electrodes that changes polarity of ions
What is current?
The movement of charged particles through a conductor in response to an applied electrical field
how fast the electrons are moving
1 Amp = 1C of charge/sec
What is voltage?
potential difference or electromotive force (EMF); a driving force that makes charged particles move; change in electrical potential energy b/w two points in an electric field/unit of charge
how much potential to drive the flow of electrons (9V battery has less potential difference than 12V battery)
1 volt = 1 Amp of current containing 1 ohm of resistance
Voltage in hourglass
How much sand at the top to flow down
Current in hourglass
how fast the sand flows down
Resistance
Opposition to current (movement of charge particles); Flow of current inversely proportional to resistance
What is Ohm’s Law?
I = V/R
resistance is equal to:
Rho * (length/cross-sectional area)
What is Ro?
Rho= inversely proportional to water content
What is Ro?
Rho= inversely proportional to water content
resistivity in biological tissues is inversely proportional to water content
Virtually all resistance at electrode-skin interface
What is Ro?
Rho= inversely proportional to water content
resistivity in biological tissues is inversely proportional to water content
Virtually all resistance at electrode-skin interface
What does skin and fat do to electrical current?
provides resistance
What happens when resistors are in parallel?
1/resistance added for each resistor
Between each electrode, what is providing resistance?
skin and fat in series (primary form of resistance), then n., m., and bone/other forms of resistance are in parallel
While using NMES, 100 Volts meet 4.467k Coulombs.
What is the current reaching the peripheral nerves that innervate the m.?
V = IR
I=V/R
0.02 A or 20mA = 100 V/ 4,467 C
What are the two applications of Ohm’s Law?
How can resistance change in a patient?
Constant Current Devices: Current constant despite R changes
Constant Voltage Devices: Constant V despite changes in R
Incision, perspiring, swelling, dying out of the electrode
What would happen if imedance suddenly drops from 4.476 kCoulombs to 1 kCoulombs with a constant voltage device (100V)?
I = V/R
I = 100V/1000C
I = 0.1 A or 100mA
Current is higher
What would happen if imedance suddenly drops from 4.476 kCoulombs to 1 kCoulombs with a constant current device (0.02 A)?
V = IR V = 1000 Coulombs * 0.02 A V = 20 V
Where does current flow?
How does this affect current flow when there is a break in the skin?
When electrodes touch?
When the electrodes are dry?
the path of least resistance
Current becomes much greater due to less resistance where the break of the skin lies
Brings a lot of current through a really small area
Sweat adds resistance; dryness prevents sticking and can also cause resistance
What is the main reason for DC stimulation? What is this used for?
iontophoresis: Administers medication transdermally
Uses the polarity of drugs to push it into the tissue
What are the therapeutic effects of DC current on the body? Effects when applied in excess?
therapeutic flow of ions to change polarity,
local increase in blood flow to restore pH
blistering, chemical burns, reaction is more caustic to skin
What is the direction of flow of ions in regards to a black cathode and a red anode
Electrons flow towards the “negative” cathode and away from the anode “positive”
Contraindications for EStim
Cardiac problems-pacemakers/ICDs (less worrying for LE) Electronic devices Carotid Sinus Larynx Pregnancy (low back/abdomen) Broken/damaged skin DVT (local) CA (local) Recently radiated tissue Chest (cardiac issues) Neck/head (seizures) On or near eyes
mostly considered risk vs reward
don’t do it over life sustaining organs
What are precautions for Estim?
Open skin lesions Skin conditions Open epiphysis Mental status Reduced sensation Allergies Metal implants Cognitive/communication impairments
What Estim requires specialized training?
Transcranial Direct Current Stimulation
Reproductive organs/genitalia
What does a bipolar set up consist of?
two channels
two electrodes
What does a quadripolar set up?
Four electrodes
Unipolar setup?
one active electrode/ultrasound head along with a large dispersive electrode to find source of pain
not commonly used
