01 Heat + Cold

how deep into skin is superficial vs deep heating? where to use each?

superficial: 1-3 cm, skin, subcutaneous tissue/fluids

deep: 3-5 cm, large muscles and joints

what are the types of heat transfer?

conduction

convection

radiation

conversion

what is conduction? what are types of modalities?

direct contact to transfer energy

hot packs, paraffin, cold modalities

what is thermal conductivity?

rate that material transfers heat

what is rate of heat transfer?

(area of contact x thermal conductivity x temperature difference)/tissue thickness

what is convection? types of modalities?

circulating medium and material of a different temperature, thermal agent is in motion. often a faster process than conduction when comparing same starting temps

fluidotherapy, whirlpool

what is radiation? types of modalities?

energy transfer without contact or intervening material

infrared lights

what does radiation rate depend on?

radiation intensity, size and source of radiation, treatment area, distance and angle between source and treatment area

what are the types of conversion of nonthermal energy to heat?

mechanical - ultrasound

electrical - diathermy

chemical - cold packs activated by striking

what is evaporation? modality?

process of a liquid changing to a gas (cooling only!!)

vapocoolant sprays

what is specific heat?

the amount of energy required to raise the temperature of a unit of mass of a material by 1ºC (in J/g/ºC)

indications for therapeutic heat

decrease pain, muscle spasm, joint stiffness; increase soft tissue extensibility and ROM; general relaxation and may decrease DOM

what are examples of deep heating agents?

ultrasound

diathermy

what are examples of superficial heating agents?

hot packs, paraffin, infrared, fluidotherapy, hydrotherapy

tissue temperatures must be elevated to __-__ to provide a therapeutic effect.

103-113ºF

the greater the __________, the greater the changes.

area being heated

what are the effects of heat?

vascular/hemodynamic effects

neuromuscular effects

metabolic effects

altered tissued extensibility

what are the vascular effects of heat?

vasodilation - relaxation of smooth muscle

minimal impact skeletal muscle blood flow

increased metabolic reactions - increased metabolic rate, chemical mediators, increased O2 for repairs

what are neuromuscular effects of heat?

increased nerve conduction velocity - increases thermoreceptors at skin, decreases nociceptive afferents at dorsal horn

decreased pain, analgesics

psychosomatic effects

what are the neuromuscular effects of heat?

activates spinal pain gating mechanism → increased pain threshold, decreased muscle spasms and ischemia

what are muscular effects of heat?

decreased alpha mn, relaxation of GTO leading to relaxation of muscle contraction

decreased muscle performance then increases for the next 2 hours

T/F muscle are deep and need more than superficial heat, so exercise is better to increase blood flow

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what are metabolic effects of heat?

heat increases metabolic rate leading to increased O2 uptake by tissues

could promote tissue healing but not past 113-122ºF!! tissues will burn!

benefits to applying heat to soft tissues prior to or while stretching

maintains greater increase in length

requires less force for stretching

decreases risk of tissue tearing

how to increase tissue extensibility with heat? temperature and time

104-113ºF for 5-10 min

what does literature say about heat for flexibility?

beneficial, cold may have opposite effect

in HS, not significant difference when heat/cold applied

what does literature say about heat applied for pain?

improved QOL with 20’ of heat

low-level heat wrap is better than acetaminophen and ibuprofen for LBP

superficial heat therapy provides pain relief, improves musc strength and increases flexibility for mild to mod LBP

what does literature say about heat for DOMS?

pain relief 24 hrs s/p exercise 138% greater with heat wrap vs cold

chemical moist heat wraps reduced DOMS more than MH or thermacare heat wraps

what are contraindications to heat therapy?

impaired sensation

vascular disease/insufficiency

thrombophlebitis

over recent or potential hemorrhage

over area of known malignancy

over infected area

over lidocaine patches

impaired cognition

what are precautions for heat therapy?

over area of acute injury or inflammation

over abdomen or low back during pregnancy

impaired circulation

metal in area

area of edema

over area where liniments or heat rubs were recently applied

cardiac insufficiency

over an open wound

demyelinated nerves

what are adverse effects of heat therapy?

burns - cell death secondary to protein denaturation

fainting - peripheral vasodilation, decreased blood pressure/heart rate

bleeding - vasodilation - avoid in acute trauma, hemophilia, recent vascular lesions

what temperature should hot packs be stored in?

158-167ºF

how many layers before putting on a hot pack?

6-8 layers

what is procedure when putting on hot packs?

check for contraindications/precautions

check sensation!

explain treatment/call bell

remove jewelry and clothing that contains metal

check skin → 5 min check in → apply for up to 20 min → check area after

what is the temperature paraffin provides?

125-134ºF

what is procedure for applying paraffin?

check sensation!

explain treatment/call bell

remove jewelry, check sin, wash and dry area

dip and repeat 6-10 times (same with painting technique), wrap with plastic and cover with towel until wax cools

inspect skin after

what temperature for fluidotherapy?

100-118ºF

procedure for fluidotherapy?

control heat and particle agitation

portals in unit so therapist can access patient during treatment

patient can perform ROM during treatment

applied for ~20min

general procedure for therapeutic heat application

1. explain purpose, procedure, expectations to patient

2. clear contraindications

3. check sensation

4. apply agent

5. perform 5 min check

6. after treatment inspect skin and document results

what are indications to cryotherapy?

inflammation

pain

edema

reduce spasticity

facilitation of movement

increase pain threshold

what does cooling depend on?

temperature difference between objects

time of exposure

conductivity of tissue - higher water content is better conductivity, adipose is an insulator - resists heat and cold

type of agent

total body surface being cooled

what are the effects of cold therapy?

hemodynamic, neuromuscular, metabolic

what are the hemodynamic effects of cold?

immediate vasoconstriction → decreases

smooth muscle of blood vessel walls contract, decreased production of vasodilator mediators, increased blood viscosity, reflexes causing vasoconstriction

how long for cold induced vasodilation to occur?

5-10 min, longer period of time with less intense cold

limit cold to _____ min to limit vasodilation

5-10 min

what are the neuromuscular effects of cold?

decreased nerve conduction velocity

increased pain threshold

alters muscle force generation

decreases spasticity

alters proprioception

decreased nerve conduction velocity from cold has the greatest effect on what nerves?

myelinated and small nerves, esp A-delta pain transmitting fibers (small-diameter and myelinated)

how does cold increase pain threshold?

reduces sensory nerve conduction velocity

reduction of local blood flow to injured area → reduction of muscle spasm, inflammation, edema

myofascial pain and trigger points improved

when applying cold to muscle

____ min = increased muscle strength

____min = decreased muscle strength

cooling ____ min = decreased isometric strength initiailly

<5

>5

5-10

how does cold temporarily alter muscle strength?

decreased blood flow, slowed motor nerve conduction, increased joint stiffness

cooling 10-30 min…

decreases spasticity, clonus, resistance to PROM and some reflexes

cold decreases/increases metabolic activity

decreases

T/F cold can be used to treat/control acute inflammation

T/F cold is recommended when healing is delayed

T/F cold can treat inflammatory joint disease (OA/RA) by decreasing activity of collagen degrading enzymes

T

F

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how to use cold pack for inflammation control?

immediately after injury and during acute inflammatory phase to help control bleeding, edema, and acute pain

how long to apply cold for inflammation control?

no longer than 20 min at least 1 hour apart

when should you discontinue cold therapy?

after inflammatory phase

cryotherapy applied for 10-15+ min can control pain for ___ hours

1+

cold can temporarily reduce spasticity in patients with?

upper motor neuron dysfunction

how long to apply cold to decrease clonus and resistance of muscle to passive stretch?

10-30 min

cold therapy can be used for what neurologic condition?

MS

it takes longer/shorter for a cooled area to return to normal temperature than a warmed area.

longer

cold therapy contraindication

cold urticaria

cold intolerance

cryoglobulinemia

Raynaud’s disease/phenomenon

paroxysmal cold hemoglobinuria

over regenerating peripheral nerve

over area of circulatory compromise

over area of PVD

cold therapy precautions

HTN

thermoregulatory disorders

over a superficial peripheral nerve

over an open wound

poor sensation

poor cognition

the very young and very old

persons with aversions to cold

what are adverse effects of cold therapy?

tissue death

frostbite

nerve damage

always keep tissue temperature above __ºF.

59

cold packs reduce temperature of skin/tissues up to __ deep.

2 cm

cold pack application procedure

screen for contra/precautions, check sensation

explain procedure and purpose

remove jewelry and clothing from treatment area

inspect area

drape as needed, pt positioning, elevation if edema

use 1 layer of towel if agent <30ºF

treatment time is 10-15 min, call bell

check pt ~5 min after tx initiation

after tx check skin and document

what are normal reactions to cold therapy?

intense cold

burning

aching

numbness

anesthesia

ice massage indication

small area

how long to do ice massage

until analgesia or 5-10 min to pt tolerance

vapocoolant spray indications

trigger points, muscle tension/spasm, minor sports injuries

vapocoolant spray tx procedure

drape and position pt

apply 3-5 parallel sweep sof spray 0.5-1 min apart at 4 in/sec. hold 12-18 sec away from skin

have pt take a deep breath and passively stretch muscle while pt exhales

cold compression indications

pumps cold water into sleeve around pt extremity

applies compression

what is the adjustable temperature range for cold compression

50-77ºF

what is contrast bath?

decreases edema and pain and promotes desensitization

contrast bath: temperature range for hot and cold baths, time in hot and cold baths, reps and time?

heat: 100-111ºF x 3-4 min

cold: 50-64ºF x 1 min

repeat 5-6 times for total of 20-30 min

end with heat unless edema

what to include in documentation for heat/cold?

modality type

time/duration

area treated

positioning

note compression or elevation

skin pre- and post-

reactions/pt response

pt education/handouts

outcomes: ROM, pain, function, flexibility, muscle spasms