Electrophysical agents: Heat & Cold

Heat & Cold :Heat & Cold Dr Shea Palmer (script) Mr Chee-Wee Tan (narration)


Thermal Agents :Thermal Agents Effects of adding energy to matter: 1. *  kinetic energy (& vice versa) 2. *  temperature (& vice versa) 3. Expansion of material (or compression) 4. Change in state * = clinically important effects


Thermal energy is transferred by: :Thermal energy is transferred by: Conduction - kinetic motion between atoms & molecules (solids - hot pack) Convection - movement of molecules/ atoms from one place to another (liquids/ gases - hot/cold baths, sauna) Radiation - heat converted to electromagnetic radiation (Infra-Red, Ultraviolet Radiation, Short-wave Diathermy)


Safety Testing :Safety Testing MUST ENSURE NORMAL SENSORY FUNCTION - DANGER OF BURNS 2 test-tubes (40-45oC & 15-20oC) Instruct subject to close eyes Randomly apply to treatment area and ask subject to identify which is hot/ cold


Therapeutic Heat :Therapeutic Heat


Therapeutic Effects of Heat (1) :Therapeutic Effects of Heat (1)  pain - Gate control,  muscle spasm, sedation, counterirritant  muscle tone/spasm possible  muscle strength  healing - optimum is above core temperature  blood flow


Therapeutic Effects of Heat (2) :Therapeutic Effects of Heat (2)  ROM -  pain,  spasm,  viscosity,  collagen extensibility Sedation/ psychological/ placebo effects Reflex heating - contralateral/ distal areas


Slide 8 :Effects of Heating From Low & Reed (2000)


Heat - Application Methods (1) :Heat - Application Methods (1) 1. Heat Packs Mud absorbs hot water. Wrap in towelling before application - 8min to max heat (20-30min Tx) Towelling on top to insulate Check after 5 minutes Hot water bottles for home application


Heat - Application Methods (2) :Heat - Application Methods (2) 2. Paraffin Wax (good for extremities) Temp = 42-50oC Dip & Wrap: In 1 sec/ out 2-3 sec/ in 1 sec… (repeat x6-12). Wrap in plastic bag & towelling/ elevate - 15min Dip & Stay: In & out as above, then in for 15-20min ( temperatures) - elevation not possible. 3. Hydrotherapy 36-41oC


Paraffin Wax Bath :Paraffin Wax Bath


Heat - Application Methods (3) :Heat - Application Methods (3) 4. Contrast Baths Alternate hot & cold. Marked hyperaemia & sensory stimulation (hot & cold receptors stimulated++).  pain (Gate theory) & swelling (vasoconstiction/ vasodilation). 2 baths (40-45oC & 15-20oC). Start & finish in hot (3-4min hot & 1min cold). 10-25min total.


Contraindications to Heat :Contraindications to Heat Lack of thermal sensitivity Impaired circulation Recent bleeding/ haemorrhage Devitalised skin (e.g. after deep X-ray treatment) Open wounds Skin conditions (e.g. skin carcinoma, acute dermatitis) Cardiovascular impairment (if large body part to be treated) Damaged/ infected tissues Kitchen (2002) pp.132


Therapeutic Cold :Therapeutic Cold


Therapeutic Effects of Cold (1) :Therapeutic Effects of Cold (1) Acute injuries -  blood flow, pain, metabolism and secondary cell death  pain - Gate theory,  hypertonicity,  nerve conduction (A fibres), ‘counterirritation’  muscle spasm - a\a  spasticity - reflex inhibition from skin receptors,  viscosity ( stretch reflex), desensitises muscle spindle if prolonged


Therapeutic Effects of Cold (2) :Therapeutic Effects of Cold (2)  swelling -  blood flow / exudate  muscle strength - brief stimulation facilitates contraction


Slide 17 :Effects of Cooling From Low & Reed (2000)


Cold - Application Methods (1) :Cold - Application Methods (1) 1. Ice Packs Best application is crushed ice in damp towelling (ACPSM 1998) Alternatively ice in plastic bag with damp towel between it & skin Further towelling on top to insulate Check after 5 minutes Apply for 20-30min every 2hrs (ACPSM 1998)


Cold - Application Methods (2) :Cold - Application Methods (2) 2. Ice Cube Massage Ice cube in paper towel - slow circular movement until numbs (5-10min) For muscle stimulation use short strokes over dermatome 3. Immersion 16-18oC for 15-20min If lower temperature used - intermittent immersion


Contraindications to Cold (1) :Contraindications to Cold (1) Arteriosclerosis Peripheral Vascular Disease Vasospasm e.g. Raynaud’s disease Cryoglobinanaemia (may be associated with RA and systemic lupus erythematosus) Cold urticaria (histamine release leads to weal formation, itching, erythema, decreased blood pressure and increased heart rate.


Contraindications to Cold (2) :Contraindications to Cold (2) Cardiovascular impairment (if large body part to be treated) Lack of thermal sensitivity Skin hypersensitivity Adverse psychological factors e.g. strong dislike of cold Kitchen (2002) pp.135


Summary :Summary Very common modalities with powerful physiological and therapeutic effects Home treatment advantageous Directed reading details evidence for those effects Many other electro-physical modalities claim to heat the tissues, thereby eliciting similar effects