Cooling Agents

Cryotherapy

Remove heat from body

NOT ADD COOLANT

How do cooling agents work?

Energy transfer from warm → cold tissues by conduction

High energy mol collide w/ low kinetic energy ones to achieve thermal equilibrium

What factors determine body’s response to coolant….

• Body’s ability to maintain homeostasis [circulation + tissue comp/fat]

• Thermal gradient [diff in temp btwn agent + tissue]

• Exposure time

• Vol of exposed tissue

• Application

• Type of agent

Pathway of Heat removal

Body → wet towel underlay → cooling agent

• Body mol heat mol in wet towel → heats mol in cooling agents

• MOL DON’T CHANGE LOCATION, THEY JIGGLE

Ice pack cooling deeper tissues

Surface temp rapidly drops

• Subcutaneous longer

Deep tissue (4cm) gradually ↓ temp due to vasoconstriction and ↓ nerve conduction

• Vasoconstriction + dilate to keep heat

• 10-12 mins to cool skin

When will skin temp stabilize?

Near-freezing levels

Skin temp ↓ more if vital organs are too cold

Duration to cool superficial structures

10 mins

Duration to cool deeper structures

20 min

Duration for pain relief

10 min

• Take less meds

Hypoalgesia + cooling agents

Reduced sensitivity to pain bc…

• ↓ nerve conduction velocity

• Modulation @ SC

Superficial cooling + swelling

Reduced BF bc vasoconstriction

• Prevents FURTHER edema formation

  • ICE ALONE DOESN’T REDUCE SWELLING

Cooling agent does what to cellular metabolism?

↓ metabolism, ↓ need for O2

• ↓ risk of secondary injury/tissue hypoxia

What happens to tissue metabolism w/ inflammation

Heightened metabolic activity due to inflammatory cells

• Further injury bc of tissue hypoxia

  • O2 supply can’t keep up w/ demand

Debate on ice + healing process

Ice bad bc tissue is weaker, stops/slows down natural healing process

PEACE & LOVE

Protect

Elevate

Avoid anti-inflammatories bc reduce healing?

Compress

Educate

Load

Optimism

Vascularization: pain-free cardio to increase BF

Exercise: restore mobility, strength, proprioception

Alternation btwn vasoconstriction and vasodilation

To conserve heat loss

Protects skin from ischemia (Lewis Hunting Reaction)

• Skin appears molted

Contractibility + Extensibility

Impairs contractility

• ↓ twitch amplitude, duration, rate of force

• ↑ motor units recruited, firing rate of MU to produce same force

Impairs extensibility

• ↓ Ligament extensibility bc collagen extensibility (<36°C)

• ↑ Mm + joint stiffness bc viscosity

DO NOT COOL DEEP STRUCTURES BE4 EXERCISE

Crushed Ice Application

10-20 min, repeated 2-4 hourly

• 30-40 min if over bandage/cast

Compression + elevation to ↓ swelling

NO WHITE SKIN

• NEED DAMP TOWEL UNDERLAY TO ↑ COOL RATE

• Air in bag makes it warmer

Cold Bath Application

Cont immersion: 20°C x 15 min OR 16-18°C for 10 min. temp dictates time

Repeat 2-3 hr

• Agitate water to redistribute cold

• 20°C x 1 hr: more edema

• 10°C x 20 min: more edema

  • Vasoconstrict harder to return back

Thermal sense + pain merge @ <15 C

Cold whirlpool

28-30°C x 5 min

Patient exercises during immersion

Follow w/ compression + exercise

• Exercise mobilizes swelling

Cool spray application

• Mm on passive stretch (lengthened)

• Spray ethyl chloride in unidirectional sweeps, proximal-distal

• Stretch mm actively or assisted

• Respray + stretch 3-4x

• Repeat treatment after skin is rewarmed

Sub spray w 3 min ice massage

Considerations for Cooling Agents

• EPAs used as adjunct, NOT ISOLATION

• Choose based on therapeutic goals

• Document under OBJECTIVE

Preparing patient for rx

• Explain expected sensations + procedure

• Explain benefits/risks

• Explicit consent

• Screen for contraindications/precautions

• Make patient comfortable

• Instruct on how to get attention

• Check in during procedure

How to deal with adverse events

Document

Follow policy/procedure

Notify patient, seek medical advice

Contraindications

• Cold urticaria (cold allergy/hypersensitiity)

• Raynaud’s disease

• Cryoglobulinemia

• Hemoglobulinemia

• Impaired circulation

• Near chronic wounds

• Regenerate nerves

• Tissues affected by tuberculosis

• Haemorrhaging tissue in those w/ untreated haemorrhagic disorders

• Active deep vein thrombosis/thromophlebitis

• Anterior neck + carotid sinus

• Home cold therapy programs NOT for persons w/ cognitive/communication problems [can’t follow directions]

Contraindication - COWSAID

Cognitive deficit

Morbid Obesity

Open Wounds

Loss of Sensory discrimination

Cold Allergy

Tissue Ischemia

Dermatitis