Hemodynamic Effects Immediate vasoconstriction Less than 15 minutes Stimulates smooth muscles of vessels to contract Decreases release of histamine, prostaglandins (vasodilators) Increases blood viscosity (increases resistance to flow) Decreases blood flow to maintain core temperature
Hemodynamic Effects After 15 minutes, vasodilation occurs Mostly distal extremities Temperatures < 10 C (350 F) >15 minutes Cold induced vasodilation (COVD) Amount of vasodilation usually small Skin redness NOT due to vasodilation Due to increase in oxyhemoglobin concentration of blood Cold decreases oxyhemoglobin dissociation Makes less oxygen available to tissues Hunting Response Response to pain associated with extreme cold
Decreased Nerve Conduction Velocity Proportional to degree and duration of temperature change Application of cold > 5 minutes Reverses (normal) within 15 minutes After 20 minutes, may take 30 minutes or more to recover.
Decreased Nerve Conduction Velocity Decreased NCV of sensory and motor nerves occurs Greatest effect in myelinated, small fibers pain transmitters Least effect in unmyelinated, large fibers
Increased Pain Threshold Counter-irritation via Gate Theory Secondary to decrease in muscle spasm Secondary to decrease in sensory NCV Secondary to post-injury edema reduction (decreased blood flow) Reduces pressure on nerves due to edema
Decreases Spasticity Decrease in gamma motor neuron activity (stretch reflex) After 10-30 minutes, decrease in afferent spindle, GTO activity. Caused by decrease in muscle temperature Can last for 1- 1.5 hours So… Application of cold up to 30 minutes in patient with increased tone, will decrease tone for up to 1-1.5 hours
Facilitation of Muscle Contraction Brief application (few seconds) facilitates alpha motor neuron activity Produces muscle contraction in flaccid muscle. CVA, SCI Prolonged cold (few minutes) decreases force of contraction
Decreases Metabolic Rate For inflammation For healing not recommended for patient with delayed healing Cartilage-degrading enzymes decreased OA, RA
Inflammation Control Decreases chemical reactions secondary to acute inflammatory response Decreased blood flow secondary to vasoconstriction, increased viscosity Causes secondary decrease in bleeding, edema (normally) Increased function during this stage of healing
Inflammation Control If temperature of tissue remains elevated… Cryotherapy remains indicated (48-72 hrs) After activity there is secondary acute inflammatory response may need to continue cold for some time
Inflammation Control Prophylactically after exercise to decrease DOMS Delayed Onset Muscle Soreness Due to muscle connective tissue damage secondary to exercise
Inflammation Control Duration of treatment typically 15 minutes , except spasticity control In general, applications 1 hour apart Tissue temperature can return to normal
Edema Control Decreases intravascular fluid pressure via decreasing blood flow, increased viscosity Most effective if applied immediately, in conjunction with elevation and compression
Edema Control Cryotherapy ineffective with edema secondary to immobility and poor circulation.
Pain Control 10-15 minute application can control pain for 1 or more hours. Facilitation Rarely used. (Rood)
Cryokinetics Purpose: To apply cooling agent to point of numbness shortly after injury, to decrease sensation of pain, allow patient to exercise toward regaining ROM ASAP. (Athletics) Cold for 20 minutes (numbness) Exercise for 3-5 minutes Re-cooling Repeat about 5 times
Cryostretch Cooling prior to stretching Decreases spasm, secondary increase in ROM Spray n’ Stretch, Fluoro-methane Spray If patient condition not improving or worsening within 2-3 treatments, Approach should be re-evaluated and changed, or Refer to MD
Contraindications for Cold Coldhypersensitivity or intolerance Cryoglobulinemia Uncommon disorder Aggregation of serum proteins in distal circulation when distal extremities cooled Proteins form a “gel” that can impair circulation, Causes local ischemia, gangrene Paroxysmal Cold Hemoglobinuria Release of hemoglobin into urine from lysed red blood cells, In response to local or general exposure to cold
Contraindications for Cold Raynaud’s Disease Paroxysmal digital cyanosis Sudden pallor followed by redness of skin of digits, Precipitated by cold or emotional upset Relieved by warmth Bilateral and symmetric (women) Raynaud’s Phenomenon Generally only in one extremity May be associated with thoracic outlet, carpal tunnel syndrome or trauma
Contraindications for Cold Regenerating Nerves Local vasoconstriction or decreased nerve conduction may delay regeneration Circulatory compromise or peripheral vascular disease Chronic peripheral vascular disease may have edema Cold may increase this edema Indicators for swelling due to Peripheral vascular disease Pallor and coolness
Precautions Over superficial main branch of a nerve Over an open wound delays healing Hypertension can cause transient increases in systolic or diastolic BP Patients with poor sensation or mentation Very young or very old impaired temperature regulation, ability to communicate
Adverse Effects Tissue Death Frost Bite Nerve damage Unwanted vasodilation due to prolonged vasoconstriction, ischemia, thromboses in smaller vessels. Freezing of tissues damage at 39 degrees F To avoid, duration limited to under 45 minutes and tissue temperature above 39 degrees F When goal is vasoconstriction, treatment limited to 10-15 minutes
Application of Cold Assess patient and establish goals of treatment Determine if cryotherapy most appropriate treatment No Contraindications Select appropriate mode of application based on body part and desired response Explain procedure, reasons for treatment, and expected sensations
Sensory Response to Cryotherapy Due to stimulation of thermal receptors and pain receptors followed by blocking of nerve conduction In this order: Intense cold Burning Aching Analgesia, numbness
Cold Packs/ Ice Packs Commercial Silica or mix of saline/gel Stored in freezer at 23 C Moldable to patient’s body Should be cooled at least 30 minutes between treatments or 2 hrs. prior to initial use.
Application of Cold Ice Bags Crushed ice best conforms better Get all/most air out of bag. Colder than ice packs specific heat of ice higher than gels Either decrease time or provide slight insulation.
Application of Cold Packs Home Treatment Ice bags, or frozen peas/vegetables Remove frost from outside of bag or insulate with towel. Homemade cold packs 4:1 mix of water, rubbing alcohol
Application of Cold Pack/ Ice Bags Use warm damp towel with cold pack, dry towel with ice bag (?) Secure pack with strap or ace wrap Elevate extremity if indicated Position patient comfortably Check skin periodically Give bell/ set timer
Ice Massage Ice cups or frozen water “Popsicles” Styrofoam nice, but often bust as ice expands
Application of Ice Massage Use towels in surrounding areas to catch drips. Use small, overlapping circles Keep ice moving rapidly Continue for 5-10 minutes or until analgesia achieved “Quick Icing” used as quick strokes with ice cup to facilitate motor response
Advantages of Ice Massage Treatment area can be observed during treatment Excellent for small, irregular areas Short-duration of treatment Increases compliance Can elevate limb if desired
Disadvantages of Ice Massage Requires clinician throughout treatment, unless patient independent