lecture content • Cryotherapy• Effects of Cold • Clinical Indications for Cryotherapy • Contraindications for Cryotherapy • Precautions for the Use of Cryotherapy • Adverse Effects of Cryotherapy
• Cryotherapy, the therapeutic use of cold .
• In PT, cryotherapy is used to control inflammation , pain, and edema; to reduce spasticity; to control symptoms of multiple sclerosis ; and to facilitate movement.
Spasticity • Pathological increase of tone • An increased rigidity of muscles due to brain or spinal cord injury.
Initial Decrease in Blood Flow This vasoconstriction persists as long as the duration of the cold application is limited to less than 15 to 20 minutes.
Effects of Cold Hemodynamic Effects
Initial Decrease in Blood Flow(Cont.)
body reduces blood flow It is thought that the body reduces blood flow in response to decreased tissue temperature to protect other areas from excessive cooling and to stabilize core body temperature. so Vasoconstriction occurs first to reduce heat loss The less blood that flows through an area being cooled, the smaller volume of blood that is cooled, and the less other areas in the circulatory system are affected
Later Increase in Blood Flow • When cold is applied for longer periods of time or when the tissue temperature reaches less than 10°C (50°F), vasodilation may occur. This phenomenon is known as cold-induced vasodilation (CIVD)
cold-induced vasodilation (CIVD) When cold is applied for longer periods of time or when the tissue temperature reaches less than 10°C (50°F), vasodilation may occur. This phenomenon is known as cold-induced vasodilation (CIVD) and was first reported by Lewis in 1930, Lewis correlated this temperature cycling with alternating vasoconstriction and vasodilation and called this the hunting response . It is generally recommended that cold be applied for no more than 15 minutes, particularly when the distal extremities are treated.
Cold-induced vasodilation (CIVD) hunting response Although the increase in skin redness seen with the application of cold may appear to be a sign of CIVD, this change is actually thought to be primarily the result of an increased concentration of oxyhemoglobin in the blood caused by a decrease in oxygen-hemoglobin dissociation that occurs at lower temperatures . Because cooling decreases oxygen-hemoglobin dissociation, making less oxygen available to the tissues, CIVD is not an effective way to increase oxygen delivery to an area.
Decreased Nerve Conduction Velocity • Although decreased nerve conduction velocity can occur if a superficial cooling agent is applied to the skin for 5 minutes or longer, it fully reverses within 15 minutes in individuals who have normal circulation. • However, after 20 minutes of cooling, nerve conduction velocity may take 30 minutes or longer to recover as a result of the greater reduction in temperature caused by the longer duration of cooling
Reduced Pain and Increased Pain Threshold • Increase the pain threshold. • Decrease the sensation of pain. • “counterirritation via the gate control mechanism and reduction of muscle spasm, slowing of sensory nerve conduction velocity, or reduction of postinjury edema”.
Altered Muscle Strength • Depending on the duration of the intervention and the timing of measurement, • Cryotherapy has been associated with both increases and decreases in muscle strength.
• Depending on the duration of the intervention and the timing of measurement, • Cryotherapy has been associated with both increases and decreases in muscle strength. • Isometric muscle strength has been found to increase directly after applying ice massage for 5 minutes or less. • Proposed mechanisms for this response to brief cooling include facilitation of motor nerve excitability.
Altered Muscle Strength (Cont.) • In contrast, after cooling for 20 minutes or longer, isometric muscle strength decreases immediately after cooling, • This initial reduction in performance may reverse 1 hour later, when strength may be greater than precooling measures for the following 3 hours or longer .
Altered Muscle Strength(Cont.) • Proposed mechanisms for reduced strength after prolonged cooling include reduced blood flow to the muscles, slowed motor nerve conduction, increased muscle viscosity. • Therefore, it is recommended that muscle strength be consistently measured before the application of cryotherapy and that precooling strength not be compared with post cooling strength in attempts to assess patient progress.
Decreased Spasticity • A reflex reaction to stimulation of cutaneous cold receptors causing a reduction in gamma motor neuron activity. After more prolonged cooling of 10 to 30 minutes. • decreased discharge from afferent spindles and Golgi tendon organs (GTOs) as a result of decreased muscle temperature. • These later effects generally persist for 1 to 1.5 hours and therefore can be taken advantage of in treatment by applying cryotherapy to hypertonic areas for up to 30 minutes before employing other interventions to reduce spasticity during functional or therapeutic activities.
Facilitation of Muscle Contraction Brief application of cryotherapy is thought to facilitate alpha motor neuron activity to contract a muscle that is flaccid because of prolonged upper motor neuron dysfunction. This effect is observed in response to a few seconds of cooling .
Metabolic Effects • Cold decreases the rate of all metabolic reactions, including reactions involved in inflammation and healing. • Thus, cryotherapy can be used to control acute inflammation. • The activity of cartilage degrading enzymes such as collagenase, elastase, hyaluronidase, and protease and the level of histamine are reduced by decreases in joint temperature.
Clinical Indications for Cryotherapy • Inflammation Control It control acute inflammation, accelerating recovery from injury or trauma. • Decreasing tissue temperature slows the rate of chemical reactions that occur during the acute inflammatory response and reduces the heat, redness, edema, pain, and loss of function associated with this phase of tissue healing.
Cont. Clinical Indications for Cryotherapy • Thereby reducing bleeding and fluid loss after acute trauma. • Cryotherapy is thought to reduce pain by decreasing the activity of A-delta pain fibers and by gating at the spinal cord level. • Controlling the edema and pain associated with inflammation limits the loss of function associated with this phase of tissue healing.
Inflammation Control(Cont.) • Apply cryotherapy immediately after injury and during the acute inflammatory phase of healing to help control bleeding, edema, and pain and to accelerate recovery; therefore, the sooner the intervention is applied, the greater and more immediate are the potential benefits.
• To limit the possibility of excessive decreases in tissue temperature and resultant cold-induced injuries, cryotherapy applications should be at least 1 hour apart so that the tissue temperature can return to normal between treatments. • When using cryotherapy to control inflammation on the extremities, apply for no longer than 15 minutes at least 1 hour apart.
Edema Control • Cryotherapy can be used to reduce edema, particularly edema associated with acute inflammation. During acute inflammation, edema is caused by increased intravascular fluid pressure and vascular permeability that extravasate fluid into the interstitium.
• Cryotherapy reduces this intravascular pressure by reducing the blood flow into the area through vasoconstriction and increased blood viscosity. Cryotherapy also controls increases in capillary permeability by reducing the release of vasoactive substances such as histamine.
Edema Control(Cont.) PRICE P protectionRICE R rest I ICE application E Elevation C compression
Edema Control(Cont.) • To most effectively minimize edema formation, cryotherapy should be applied as soon as possible after acute trauma in conjunction with compression using an elastic wrap and elevation of the affected area above the level of the heart. • Compression and elevation reduce edema by pushing extravascular fluid out of the swollen area and into the venous and lymphatic drainage systems. • The acronym RICE refers to the combined intervention of rest, ice, compression, and elevation. • Although cryotherapy can reduce edema associated with acute inflammation, it is not effective in controlling edema caused by immobility and poor circulation.
Pain Control • The decrease in tissue temperature produced by cryotherapy may directly or indirectly reduce the sensation of pain. Cryotherapy directly and rapidly modifies the sensation of pain by gating pain transmission through the activity of cutaneous thermal receptors.
Pain Control(Cont.) • Applying cryotherapy for 10 to 15 minutes or longer can control pain for 1 hour or longer. • This prolonged effect is thought to be the result of blocking conduction in deep, pain-transmitting A delta fibers and by gating pain transmission by cutaneous thermal receptors. • The effect is thought to be prolonged because the temperature of the area remains lower than normal for 1 or 2 hours after the cooling modality is removed.
• Reducing pain through cryotherapy can directly interrupt the pain spasm-pain cycle by alleviating the muscle spasm and pain even after the temperature of the treated area has returned to normal. Cryotherapy can also reduce pain indirectly by controlling its underlying cause, such as inflammation or edema
Modification of Spasticity • Longer applications of cryotherapy can control more of the signs of spasticity, cryotherapy should be applied for up to 30 minutes when this is the goal of the intervention. • The decrease in spasticity produced by prolonged cooling generally lasts for 1 hour or longer after the intervention;
Symptom Management in Multiple Sclerosis • Some patients with multiple sclerosis are aggravated by generalized heating such as occurs in warm environments or with activity. • Cooling can reduce fatigue, muscle weakness, and postural instability in patients having heat sensitive multiple sclerosis
Facilitation • Rapid application of ice as a stimulus to elicit desired motor patterns, known as quick icing , is a technique developed by Rood. • This technique may be used effectively in the rehabilitation of patients with flaccidity resulting from upper motor neuron dysfunction .
Cryostretch • Cryostretch is the application of a cooling agent before stretching. • The purpose of this sequence of treatments is to reduce muscle spasm, thus allowing greater ROM increases with stretching.
Contraindications for Cryotherapy • Cold hypersensitivity (cold-induced urticaria)
Contraindications for Cryotherapy • Cryoglobulinemia
Contraindications for Cryotherapy • Paroxysmal cold hemoglobinuria • Raynaud disease or phenomenon • Over regenerating peripheral nerves • Over an area with circulatory compromise or peripheral vascular disease
Precautions for the Use of Cryotherapy • Over the superficial main branch of a nerve • Over an open wound • Hypertension • Poor sensation or mentation • Very young and very old patients
Adverse Effects of Cryotherapy • The most severe adverse effect is tissue death caused by prolonged vasoconstriction, ischemia, and thromboses in the smaller vessels. • Tissue death may also result from freezing. Damage can occur when the tissue's temperature reaches 15°C (59°F).
• N.B.: Cool cold packs for at least 2 hours before initial use and for 30 minutes between uses.