Superficial Heat Agents

Biophysical Basis of electrophysical

Energy from EPA interacting w/ bio tissue, causing cellular and physiological responses

• How does it interact & affect w/ tissues

What does biophysical basis depend on

Tissue composition (fat, water, connective tissue) + surrounding tissue

What does heat do?

Vasodilate skin

Thermotherapy agents

Fludiotherapy

Heat pathway to tissue

Heating agent → hot pack over → Tissue: skin, adipose, mm → Ligament

• Mol in hot pack heat mol in cover, heat mol of body

How tissues heat up

Conduction (OR radiation)

How does body regulate temperate

Convection

Remove heat to prevent over heating

Maintain homeostasis

Heating thru conduction

Interact btwn molecules energeized @ diff rates

Energy passed directly from 1 to another

Mol don’t move location; they JIGGLE + collide

Heating thru radiation

Moves linearly in the air from source to destination

i.e. Infrared radiation

• Heat up tissue the energy comes in contact w/

Convection regulation

Mol PHYSICALLY move from 1 location to another (redistribute)

Remove heat by circulation

Conductors

Material passes energy easily

i.e. metals

Insulators

• Poor conductors

• Hold heat

• i.e. Heat

Considerations for Heating agents

• High BMI: holds heat, increased risk of burn

• Metal: is a conductor. Clothes, pacemakers, jewllery

• Elderly: impaired circulation, harder to remove heat, clotting disorders (thickening of blood vessels)

Can superficial agents heat deep tissues?

NO, not deeper than 1cm

Don’t use hot pack or wax for deeper mms

*Okay for hands and feet

Benefits to Superficial heating?

• Reduce pain

• Increase extensibility/ROM

• Decrease tone

• Promote tissue healing

• Increase circulation

• Increase tissue metabolism

  • More chemical rxn, consume more O2, promote healing

• Improves fxnl outcomes

Heating + pain relief

Skin has receptors stimulated by temperature changes

Modulate pain @ SC

• Feel heat more than pain

BUT NOT IF THERE’S ACUTE SWELLING

How does heat increase extensibility?

Heat lowers fluid viscosity

• Warm honey

• Collagen is more stretchy → in tendons + ligaments

Less elastic modulus

Extensibility

Stretched/lengthened w/o damage

Resistance to stretch

No neural changes in mm lengthening

Heat decreases mm tone

Secondary to increased sensitivity of mm spindle + golgi tendon nerve endings

Less electrical activity of mm

• Higher sensitivity of spindle → more firing → more relaxation

Normal GTO/spindle response

GTO stimulated during mm contraction/stretch = mm relax

Spindle activates when mm stretched → mm relax

Increased circulation

Vasodilate vessels to ↑ blood flow

• Smooth mm relax in arterioles + venules

• Local axon reflex

• Removes inflammatory agents + pain mediators (chronic conditions)

Axonally mediated. Uncontrolled.

Causes swelling/edema

• AVOID in acute swelling

Heating increases tissue metabolism

Increases catabolic + anabolic rxns needed to degrade and remove metabolic byproducts caused by tissue damage

Ideal for tissue repair

• Apply in subacute or chronic conditions to help w/ tissue repair

Temp to store hydrocollator

70-75°C

How long to heat

20 mins

Whirlpool bath application

36- 41°C

Water agitation for pain relief

10-20 mins

Dependency [gravity diff position] + heat = swelling

Paraffin Wax Application guidelines

Wax + mineral oil (7 wax:1)

42- 50°C [50± 5]

Conduction

Fingers, wrists, hands, foot

Increase temp of joints + small mm of hand

Contrast bath application guidelines

Continuous alternating immersion of the injured area in cold + heat

• Warm: 40-45 C 6 min

• Cold: 20 C for 4 min

• Cycle 2x, end w/ warm

Monitor temp

↑ tissue volume, ↓ skin temp

No change in intramuscular temp @ 3-4 cm

Fludiotherapy Application

Dry warm air circulates in cabinet

Airborne fine particle system (cellulose)

Variable agitation

Heat + sensory stim to releve pain

Low resistance exercise

Air temp: 38-47

For 20 mins

Protect open wounds

Contraindications for Heat

Acute injury/exacerbated chronic inflammatory condition

Regions w/ suspected cancer

Infected tissues

ppl w/ tuberculosis

Active deep vein thrombosis

Impaired sensation/circulation

Tissues actively bleeding/untreated hemorrhagic disorders

Recently radiated tissues

Cardiac disease or cardiac failure/pregnancy

Cognitive/communicative impairments

Skin breakdown, edema

Productive organs

Heat-sensitive skin disease (i.e. eczema)