Lecture 8 - Heat and cryotherapy Flashcards
Thermoregulation
Physical control:
- hypothalamus
- metabolic response
- vasomotor response
- sweating
Behavioural control:
- Clothing, seeking shelter
Mechanisms of heat transfer
Conduction: heat exchange between molecules of two materials in direct contact
Convection: movement of liquid or gas between area of different temperature
Radiation: emission of electromagnetic waves
Physiological effects of heat therapy (40-45 deg)
- increased metabolic rate (13% per deg)
- vasodilation
- reduced blood viscosity
- increase collagen extensibility
- stimulate sensory nerves
> 45 deg = tissue damage
Contraindications of heat therapy
- conditions that spread easily
- circulatory insufficiency
- exisiting conditions exacerbated
- sensory loss
- unable to communicate
Application of heat therapy
select hot pack and cover in towel to there is 1-2cm between skin and pack
time: 20 mins
Cryotherapy
progressively decrease subcutaneous temperature through local body cooling via application of substance that results in heat transfer away from tissue
Effects of cryotherapy
- decreased metabolic rate (reduced tissue damage from secondary hypoxia and enzyme activity)
- vasoconstriction
- increased blood viscosity
- stimulation of sensory nerves
- reduced NCV
Ice burns
mild: erythema and skin tenderness a few hours after
severe: bruising and damage to neural tissue > 3 weeks
Contraindications of cryotherapy
- circulatory insufficiency
- existing conditions exacerbated
- sensory loss
- unable to communicate
- hypersensitive patients
- angina
Monitoring Cryotherapy
Be careful of superficial nerves
Check for adverse reactions
- at start of Rx
- after 5 mins; then regularly
- after Rx
Reactions include:
- excessive redness
- swollen mark
- systemic reaction (increased BP/HR)
Hot or Cold?
Chronic conditions benefit equally; preference
Acute injuries = cold
