Cryotherapy & Thermotherapy Chapter 4 Therapeutic Modalities

Physiology Basics Vasodilation Vasoconstriction Increased size of vascular structures Means more oxygen to the tissue Vasoconstriction Decreased size of vascular structures Useful for preserving compromised/injured cells/tissue

Physiology Basics Analgesia Metabolic rate Inflammation Diminished/reduced sensation Metabolic rate Activity level of cells Reducing MR can preserve cells damaged by injury Inflammation Series of events that hinder optimal function

Modalities Alter cell metabolism Each 1.8°F (1°C) change in tissue temp. results in a 13%  or  in the tissue’s metabolic rate. Energy absorbed by one tissue later can’t be transmitted to deeper layers. Law of Grotthus-Draper The more energy absorbed by superficial tissues  the amount absorbed by deeper tissue.

5 Mechanisms of Energy (Heat) Transfer in the Body: Added or Removed Conduction – transfer of heat through the direct contact between a hotter and a cooler area (2 objects touching each other) Ice Massage, Hydrocollator Pack, Ice Pack Convection – transfer of heat by the movement a medium (air, liquid) between regions of unequal temperature Whirlpool Conversion – energy is changed from one form to another; does not relate to superficial heat or cold Electrical energy into heat, Acoustical energy into heat Ultrasound, Diathermy

Mechanisms of Energy Radiation – emitted from surfaces with temperatures above absolute 0° (all atomic & molecular motion ceases) Transfer of energy without the use of a medium Body, Sun, Infrared lamp, LASER, Ultraviolet light Evaporation – change from liquid state to gaseous state requiring thermal energy be removed from the body Vapocoolant Spray

Cryotherapy – Cold Therapy Cold modalities range in temp. between 32°F-65°F Heat is removed from the body & absorbed by the cold modality Tissue temperature is LOWERED To obtain therapeutic benefits, the skin temp. must be lowered to approx. 57°F. Cold therapy applied is thought to activate a mechanism used to conserve heat in the body’s core This mechanism triggers a series of metabolic & vascular events that produce the beneficial effects of cryotherapy. Can be used during all stages of healing

Cryotherapy Normal skin temp. is approx. 91°F The deeper the tissue in the body, the higher the temp. Skin is cooler than adipose which is cooler than muscular tissue. Thermoreceptors in skin are responsive to heat or cold (more to cold than heat).

Sensations with Cold Application Burning Aching Analgesia (absence of pain)  of n. conduction velocity &  threshold are required to fire the nerve(s).

Cryotherapy Indications Acute injury or inflammation Pain Muscle spasm, acute or chronic Restoration of ROM Small, superficial, 1st degree burns Post-surgical pain & edema Neuralgia Post-exercise

Cryotherapy Contraindications Cardiac or respiratory involvement Uncovered open wounds Circulatory insufficiency Cold allergy Anesthetic skin Advanced diabetes Raynaud’s phenomenon or other Peripheral Vascular Disease Lupus Situations where the body is unable to cope with temp. change because of allergy, hypersensitivity, or circulatory insufficiency

Local Effects of Cryotherapy  cell metabolism rate – PRIMARY BENEFIT  need for oxygen Lowers tissue temperature Vasoconstriction  production of cellular wastes Prevents or limits swelling  in pain by  pain threshold  in acute & chronic muscle spasm Limits area of original injury

Deeper tissues cool more slowly & to a lesser extent than skin Muscle tissue requires longer to cool than bony areas Deeper tissue temps. have been proven to drop for several minutes following the removal of an ice pack Research has shown that deeper tissues remaining at rest will be cooled for 2 hr or more after a 20- to 30- min. ice pack application The cold modality will continue to remove body heat until temps. are (=).

Precautions Take into consideration the amount of pain that occurs during exercise after cold has been applied Be careful when applying an elastic wrap over a cold pack over superficial nerves (Nerve Palsy) Uticaria – hives

Cellular Response  cellular metabolic rate During a 20-min. treatment, cell metabolism  19% With  b. flow, there is less metabolic activity & O2 demand on the cells  need for O2 Reduces number of cells killed by lack of O2 Reduces secondary hypoxic injury damage Reduces amount of chemical mediators released in area Slows nerve conduction

Vascular Responses Vasoconstriction occurs due to stimulation of n. receptors Viscosity of blood & tissue fluids  Resistance to b. flow  Soft tissue  of 26% & skeletal b. flow  of 19% with 20-min. ice pack in injured ankles Amount of b. flow is still under debate Most studies indicate that b. flow  Because of effects associated with rubbing the skin, IM may  b. flow, at least to the skin

Tissue Temperature Changes 57°F skin temp. – optimal decrease in local blood flow 58°F skin temp. – analgesia occurs Temp. within the joint decreases proportionally to temp. of skin overlying a joint decreases Temp. changes most rapidly in skin & synovium

Muscle Spasm Cold therapy affects pain threshold  nerve conduction velocity by slowing communication at the synapse  pain by reducing the threshold of afferent n. endings.  sensitivity of m. spindles May inhibit the stretch reflex mechanism reducing m. spasm & breaking pain-spasm cycle

Inflammation Changes in cellular function & blood dynamics serve to control effects of acute inflammation. Cold suppresses the inflammatory response by:  the release of inflammatory mediators (histamine, prostaglandin)  prostaglandin synthesis  capillary permeability  leukocyte/endothelial interaction  creatine-kinase activity

Pain Control Cold therapy acts as a counterirritant Cold application affects pain perception & transmission by: Interrupting pain transmission (stimulates large-diameter A-beta n. fibers) Decreasing n. conduction velocity Reducing m. spasm Reducing or limiting edema

Systemic Effects of Cold Exposure If circulating blood temp.  0.2°F, then the hypothalamus (body’s thermoregulatory center) kicks in General vasoconstriction in response to cooling of the posterior hypothalamus Decreased respiratory & heart rates Heart rate  (wants to localize the cold area) Shivering & increased muscle tone If heart rate  too much where the core temp. reaches hypothermia

Application of Cryotherapy Ice Massage: Should not be applied during acute inflammatory stage as it’s not compatible with compression 5-15 mins. – reduces pain, desensitizes trigger points Vigorous Ice Massage Ice Pack: type of ice – cubed, flaked Commercial Cold Packs: chemical, reusable (Gel) Be aware of frostbite; use insulating layer in between Cryo-cuff/Polar Care: provide approx. 40 mm Hg Cold Water Immersion: Ice bucket: 40 °-50°F Whirlpool: 50 °-60°F Vapocoolant Spray: superficial, rapid cooling through evaporation; virtually no temperature change below epidermis; will numb area briefly (trigger points) Intermittent Compression: Segmental compression with cold

Cryotherapy Duration usually15-30 mins. Don’t apply for more than 60 minutes! Depends on skinfold thickness Ice with compression – affects deeper tissues Compression encourages  lymphatic drainage Circumferential: compression around entire area (ace wrap) Collateral: compression on both sides (aircast, gelcast) Focal: direct pressure to soft tissue surrounded by bony structure (horseshoe) Cooling of tissue: rapid at first, then slows, then levels off Skin reactions: Hyperemia, pallor

Cryokinetics for Sub-Acute Injury Stage Alternating cold therapy with exercise Use good judgment! Do not cause further harm! Place cryotherapy to body part for approx. 20 min. (analgesia feeling) Remove cryotherapy & begin active exercise Place cryotherapy back on body part once feeling/pain returns Repeat

Hunting Response 1930’s ; Lewis performed skin studies with temperature change during cold treatments. When the fingers were immersed in cold water, alternating periods of cooling & warming were seen in the skin. Thoughts were that intermittent cold-induced vasodilation (CIVD) lasting 4-6 min. after approximately 30 min. of cryotherapy application (p. 109) Stated that it prevented local tissue injury Today’s researchers state that CIVD does not occur during standard cryotherapy sessions.

Cryotherapy (Ice) Application Ice massage 7-10 minutes Excellent for muscle spasm and deep soreness

Cryotherapy (Ice) Application Ice bags, ice towels, or cold packs 15-20 minutes (no longer than 30) If using packs, be sure to avoid direct contact to protect skin! Cold whirlpool / ice immersion 5-15 minutes, 55-65 degrees Duration and temperature depends on surface area immersed

Ice Massage

Ice Pack

Chemical Cold Pack

Reusable Gel Pack

Cryo-cuff

Ice Bucket

Cold Whirlpool

Fluori-methane