Cold therapy or cryotherapy is a common and useful therapeutic modality often used by physiotherapists in treating a wide range of conditions. It is easy to apply and if care is taken over cautions and contraindications it is very safe and patients can be instructed to self treat to manage their conditions independently. Cryotherapy is most commonly used in sports and acute injury treatment and is cheap and simple to use. Cold can be applied in several different ways including cold packs, crushed ice, cubed ice or cold water devices.
The local tissues are cooled by ice therapy as the water warms up or the ice melts, taking heat away from the body part. Physiologically the main effects of cryotherapy are constriction of the blood supply, reduction in metabolism locally, cold reaction circulatory increase, decrease in tissue bleeding, swelling and oedema reduction, painkilling effect from cold effects on nerve transmission and muscle efficiency reduction. Another effect of pain reduction from cold is to reduce the amount of muscle spasticity or muscle spasm occurring.
Many conditions benefit from the use of cold therapies and the effects are used to reduce oedema and swelling after an injury, a reduction in muscle spasticity once the muscle has cooled after a certain time, a lowering in pain, acute inflammatory inhibition such as required after acute injury, facilitation of a local increase in circulation and a lessening of muscle spasm. To facilitate contraction of muscles for functional muscle re-education physiotherapists will use ice and to increase ranges of movement after injury by stimulating muscle contraction.
Tissue damage from an injury to an area increases the blood supply locally, is hotter and suffers from oedema, all secondary to heightened tissue metabolism as the area reacts to damage. At this early stage these responses need to be damped down so cold is preferred over heat which would increase them. Cold reduces inflammation, eases pain, prevents swelling and slows the metabolic rate of the injured tissues, encouraging injury healing. It is important to get the cold onto the injured part as close to the precipitating event as you can, with compression if possible. Compression has been shown to be effective and may be more important than the cold.
It is important to understand the risks to skin integrity which potentially come with using cold therapy. Contraindications to cold are understood by physiotherapists and they will examine the skin for normal sensibility and good colour with lack of broken or abnormal areas. To protect the skin integrity oil can be applied to the area before cold application. A common treatment is performed using an ice pack, made by packing crushed ice into a towel bag and applied closely to the part to be treated. Thorough wetting of the towel and eliminating any pockets of air between the pack and the skin ensure a good cooling effect.
Frozen peas in the pack are commonly used and re-used by patients as they are cheap and convenient but come with a caution. Freezer temperatures are 18 degrees centigrade below zero and skin damage can result from direct application of such a cold pack. A wet tea towel or similar cloth should always be placed between these packs and the skin to avoid the chances of local skin damage known as frostbite. Length of treatment varies from 5 to 20 minutes and a check after 5 or 10 minutes is good practice to ensure the skin is reacting normally. Overcooling of the skin can be indicated by the appearance of discrete white spots and if they appear then the treatment should be terminated.
Acute strains and sprains and pains after operation can be treated by cold within the first twenty four to forty eight hours to reduce pain and inflammation. The skin sensation under the treated areas should be normal so the patient can monitor their treatment. Contraindications to cold treatment are poor blood supply in the legs, allergy to cold, impairment of blood supply and Reynauds disease. Typical techniques are spray and stretch, cold packs, contrast baths, cold water immersion and ice massage. Spray and stretch is used in myofascial pain syndrome to treat trigger points.