Passive Care - Exam 1 (modalities)

Electrophysical agents (EPAs)

electric stimulation, heat therapy, cold therapy, mechanical energy, light

EPAs are ______, rarely are they the sole therapeutic intervention

complementary

EPAs affect the patient’s ____ in the treatment area (change internal environment)

physiology

Passive care

Dr applies the intervention to pt, pt passively received therapy

Active care

Pt has to perform an activity to achieve a therapeutic effect

Does the cause of injury change the process of healing

NO!

4 stages of healing

hemostasis (sec/min)

inflammatory/acute (hr/days/wks)

proliferation/repair (wks/mo)

remodeling/maturation (mo/yrs)

Hemostasis

initial blood clotting to stop bleeding

Purpose of Inflammatory/acute phase

defend against foreign intruders (infection)

removing damaged tissue and debris

immobilize area

Avascular/poorly vascularized tissue

won’t heal well

Signs of inflammation

heat, red, swelling, pain, loss of function (Virchow)

Inflammatory/acute phase is characterized by

vasodilation

increased capillary permeability

phagocytosis by neutrophils and macrophages

Inflammatory chemicals that cause pain

bradykinin

prostaglandins

serotonin (pain-spasm cycle)

What is the goal of the inflammtory/acute phase

limit extent of inflammation and preserve ROM via active care

**non-damaged tissue needs protection + PRICE

Proliferation/repair phase is characterized as

angiogenesis (new capillaries)

fibroblasts, chondroblasts, osteoblasts

In the Proliferation/repair phase, the extracellular matrix contains

type III collagen (weak, disorganized, begin cross-linking)

proteoglycans

What is the goal of the proliferation/repair phase

encourage and increase proliferation

decrease pain and swelling

increase pain-free ROM

begin non-weight bearing proprioceptive training

Remodeling/maturation phase is characterized by

scar contraction (can lead to joint adhesion and loss of motion)

decrease blood vessels

Type III collagen gets replaced by _____ during the remodeling/maturation phase

type I

What is the goal of the remodeling/maturation phase

increase pain-free ROM

progress proprioceptive training

regain full strength + normal biomechanics

protect + strengthen residual joint stability

Secondary enzymatic injury

lysosomal enzymes released

not specific

damage to surrounding uninjured tissue

Secondary hypoxic injury (hemorrhage/clotting/edema/spasm/hematoma)

lead to decreased O2 and nutrition

damage to surrounding uninjured tissue

Tension on connective tissue causes

increased collagen fibril diameter and #

cross-linking

collagen fibril packing density

Collagen fibers that are aligned in an organized, parallel fashion forms

greatest # of cross-linking and possess optimal strength

Physiologic effects of electrical stimulation

decrease pain and muscle spasm

reduce edema

stimulate exercise by muscle contraction

stimulate healing

Electricity (flow of electrons)

requires source of electrons

driving force = electron imbalance

path = conductor

River comparison to fluid flow

electrons are drops of water in a river

current (flow of electrons) in the flow of the river (ampere)

voltage is the waterfall…height of waterfall inc = potential energy inc

Types of Resistance

length of conductor

cross sectional area

temperature

Monophasic/Galvanic/Direct Current (DC)

current flow in one direction

net charge = positive and negative electrode

charge builds in tissue

Biphasic/Alternating Current (AC)

flow of electrons changes direction regularly (changes polarity)

net charge = balance or unbalanced

wave form = symmetrical or asymmetrical

shape = sinusoidal, square, rectangular, triangular

An equal electrical charge in both phases of a biphasic/alternating current will

minimize/eliminate polarity effect in tissues

Phase duration

time it takes current to leave isoelectric line to when it returns

Monophasic

phase duration and pulse duration are SAME

Biphasic

TWO phase durations for each pulse

Tissues respond to

phase duration (NOT pulse duration)

Amplitude

intensity or magnitude of the current

**Sensory response before motor

Peak current

max amp of current regardless of duration

A-beta is close to ____ and has a ____ threshold and therefore is stimulated first

skin; lower

The deeper the penetration, the more neuron recruitment and there

muscle fiber recruitment possible

Average current

amount of current supplied over a period of time

**Too high → tissue damage

Strength duration curve

relationship btw amp (strength) of electrical current and phase duration

If the charge of the strength duration curve is sufficient to overcome capacitance of a nerve fiber it will

depolarize

Short strength duration curves require a ______ for a nerve response

higher amplitude

Long strength duration curves require a ______ for a nerve response

lower intensity

Targeting capacitance (alter phase duration and amplitude)

use patient feedback

Patient reports tingling but no muscle twitch, which fibers are stimulated

A-beta fibers ( no A-alpha motor neurons)

Muscle contraction - which fibers are stimulated

exceeded A-alpha motor neurons

Burning/needling sensation - which fibers are stimulated

exceeded A-delta fiber capacitance

If peak amplitude fails to exceed rheobase, what occurs

nerve will not depolarize regardless of phase duration

Chronaxie

time/phase duration required to depolarize a nerve fiber when a peak current is 2x rheobase

What provides the greatest comfort for the patient

amplitude is 2x rheobase

phase duration is slightly greater than chronaxie

Frequency

number of pulses or cycles generated per second (pps or Hz)

Frequency affects the number of _______ elicited during the stimulation

action potentials

Higher frequency leads to

summation (motor neuron = tetany)

Absolute refractory period

rate limiting factor of number of impulses that can be generated by a nerve

Temporal summation of muscle contraction

A - single twitch (cx and rx)

B - summation (force from 2 twitches, no rx)

C - unfused tetanus

D - fused tetanus (stays cx, no time to rx)

Which temporal summation do we want

D - fused tetanus (stays cx, no time to rx)

Wedensky’s inhibition

stimulation at high frequency near refractory period of sensory nerve

>1000 Hz

Action potential failure

What does Wedensky’s inhibition result in

anesthesia (no pain) between the electrodes

Low frequency generators

<1000 Hz (produce action potentials)

Medium/Treatment frequency generators

1000-100,000 Hz

• Interferential - 3000-5000Hz

• Russian - 2500 Hz

Intrinsic duty cycle of 10ms on and 10ms off (10:10) creates a

burst frequency of 50Hz

High frequency generators

>100,000 Hz

**can burn pt

**Diathermy uses this

Electrode considerations - there must be ____ leads to complete a circuit

2

If electrodes are placed close together, the current is concentrated in

superficial tissues

If electrodes are farther apart the current has the potential to take a deeper path through the

nerve and blood vessels that have less resistance

Electricity doesn’t go through what substance well

air

Monopolar electrode configuration

two or more unequal electrodes (1 active, 1 dispersive)

used w/monophasic or biphasic

Reasons for monopolar electrode configuration placement

leads placed far away creates deeper penetration

greater comfort at dispersive pad

creates an electrical field w/specific polarity

Bipolar electrode configuration

2 equal sized electrodes

used w/monophasic or biphasic

**MC in TENS

Quadripolar electrode configuration

two separate medium frequency currents placed as cross currents

**MC in Interferential

Constructive interference

2 sinusoidal waves exactly in phase combine

waves supplement each other

Destructive interference

2 sinusoidal eaves exactly OUT of phase

results in cancellation of both waves

Heterodyne interference

combination of constructive and destructive interference

results in a wave with a beat effect

True Interferential current (3000-5000Hz)

2 channels, 4 electrodes (quadripolar electrode placement)

most intense where currents cross

treatment frequency is based on type of pain

Pre-modulated (pain relief)

1 channel, 2 electrodes (bipolar electrode placement)

interference occurs in machine, not body

Vector scan (larger tx area)

2 channels, 4 electrodes (quadripolar electrode placement)

cloverleaf pattern rotates

Stereodynamic

3 channels, 6 electrodes

3D interference pattern (6 petal flower shape)

Effects of IFC

pain reduction

muscle strengthening or re-education

slow bowel transit and increase circulation (not much evidence)

Interferential Treatment (beat) frequency for pain

acute = 80-150

subacute = 1-150

chronic = 1-15

Interferential treatment time and amplitude for pain

15-20min

amplitude = pt comfort

Pre-mod treatment (beat) frequency and duty cycle for strength

40-60 Hz

10:50 w/ramp time

Pre-mod treatment amplitude

pt comfort

Contraindications for Interferential and Russian Current

anterior cervical area, through chest/head

pacemakers, ICD, metal implants

abdomen/pelvis/lumbar areas of pregnant women in 1st tri

epilepsy, areas of hemorrhage, damaged skin

confused and unreliable pts

unknown etiology

Risks of interferential current

skin irritation

diathermy devices (10ft away)

Indications of Russian current

muscle re-education + retard atrophy

muscle strengthening

decrease muscle spasm through fatigue

Carrier frequency, burst frequency, and pulse rate of Russian current

carrier = 2500 Hz

burst = 50 Hz

pulse rate = 50 Hz

The carrier frequency of Russian current results in

maximally summated muscle contraction

In order to cause tetanus muscle contractions, the pulse rate has to be at least

>35 Hz

**Notes: more doesn’t cause stronger cx it promotes fatigue

Russian Current amplitude

pt tolerance

Russian current duty cycle for muscle strengthening (retard atrophy/retrain muscle)

10:50 (on/off percentage = 16.7%)

10 contractions

Russian current duty cycle for muscle fatigue (spasms)

10:10

Russian current ramp time

0.5-2 seconds

mimics voluntary contractions + eases pt into stimulation

What ramp time is the closest to actual physiological muscle contraction

0.5

Electrode placement always needs to be

parallel to muscle fibers

at motor points (btw belly and tendon/musculotendon junction)

Russian current electrode configurations

monopolar (2 unequal sized electrodes) - active electrode over target

bipolar (2 equal sized electrodes) - single muscle protocol

quadripolar (4 electrodes) - agonist/antagonists

Russian current - quadripolar 1 channel w/split lead for one muscle

used for larger muscles (single muscle protocol)

Russian current - 2 channels w/Simultaneous Co-contract

used for larger muscles (core muscles)

bilateral muscles contract together

Russian current - Reciprocal protocol

channel 1 is on while channel 2 is off

agonist and antagonist contracts alternately

Too much overlap in reciprocal russian can cause

agonist/antagonist fights